i
Windows NT®
Operating System
Microsoft Base Cryptographic
Provider
FIPS 140-1 Documentation: Security Policy
September 20, 2000 11:29 AM
Abstract
This document specifies the security policy for the Microsoft Base Cryptographic Provider
(RSABASE) as described in FIPS PUB 140-1.
®
ii
INTRODUCTION .......................................................................... 1
SECURITY POLICY...................................................................... 2
SPECIFICATION OF ROLES ........................................................ 3
SPECIFICATION OF SERVICES................................................... 4
CRYPTOGRAPHIC KEY MANAGEMENT ..................................... 9
SELF-TESTS .............................................................................. 12
MISCELLANEOUS...................................................................... 13
FOR MORE INFORMATION ....................................................... 14
CONTENTS
1
Microsoft Base Cryptographic Provider (RSABASE) is a FIPS 140-1 Level 1
compliant, general-purpose, software-based, cryptographic module. Like other
cryptographic providers that ship with Microsoft Windows 2000, RSABASE
encapsulates several different cryptographic algorithms in an easy-to-use
cryptographic module accessible via the Microsoft CryptoAPI. It can be dynamically
linked into applications by software developers to permit the use of general-purpose
FIPS 140-1 Level 1 compliant cryptography.
Cryptographic Boundary
The Microsoft Base Cryptographic Provider (RSABASE) consists of a single
dynamically-linked library (DLL) named RSABASE.DLL. The cryptographic
boundary for RSABASE is defined as the enclosure of the computer system on
which the cryptographic module is to be executed. The physical configuration of the
module, as defined in FIPS PUB 140-1, is Multi-Chip Standalone.
{ TC "INTRODUCTION" \F
SP }INTRODUCTION
2
RSABASE operates under several rules that encapsulate its security policy.
• RSABASE is supported on Windows 2000.
• RSABASE relies on Microsoft Windows 2000 for the authentication of users.
• RSABASE enforces a single role, Authenticated User, which is a combination
of the User and Cryptographic Officer roles as defined in FIPS PUB 140-1.
• All users authenticated by Microsoft Windows 2000 employ the Authenticated
User role.
• All services implemented within RSABASE are available to the Authenticated
User role.
• Keys created within RSABASE by one user are not accessible to any other
user via RSABASE.
• RSABASE stores keys in the file system, but relies on Microsoft Windows 2000
for the covering of the keys prior to storage.
• RSABASE performs the following self-tests upon power up:
− RC4 encrypt/decrypt
− RC2 ECB encrypt/decrypt
− DES ECB encrypt/decrypt
− RC2 CBC encrypt/decrypt
− DES CBC encrypt/decrypt
− MD5 hash
− SHA-1 hash
• RSABASE performs a pairwise consistency test upon each invocation of RSA
key generation as defined in FIPS PUB 140-1.
{ TC "SECURITY
POLICY" \F SP
}SECURITY POLICY
3
RSABASE combines the User and Cryptographic Officer roles (as defined in FIPS
PUB 140-1) into a single role hereon called the Authenticated User role. The
Authenticated User may access all services implemented in the cryptographic
module.
An application requests the crypto module to generate keys for a user. Keys are
generated, used and deleted as requested by applications. There are not implicit
keys associated with a user. Each user may have numerous keys, signature and
key exchange, and these keys are separate from other users’ keys.
Maintenance Roles
Maintenance roles are not supported by RSABASE.
Multiple Concurrent Operators
RSABASE is intended to run on Windows 2000 in Single User Mode. When run in
this configuration, multiple concurrent operators are not supported.
{ TC "SPECIFICATION OF
ROLES" \F SP
}SPECIFICATION OF
ROLES
4
The following list contains all services available to an operator. All services are
accessible by all Authenticated Users, the one and only role supported by
RSABASE.
Key Storage
RSABASE stores keys in the file system. The task of covering the keys prior to
storage in the file system is delegated to the Data Protection API of Microsoft
Windows 2000, a separate component of the operating system, and outside the
boundaries of the cryptomodule. When a key container is deleted, the file is
zeroized before being deleted.
CryptAcquireContext
The CryptAcquireContext function is used to acquire a handle to a particular key
container via a particular cryptographic service provider (CSP). This returned
handle can then be used to make calls to the selected CSP.
This function performs two operations. It first attempts to find a CSP with the
characteristics described in the dwProvType and pszProvider parameters. If the
CSP is found, the function attempts to find a key container matching the name
specified by the pszContainer parameter.
With the appropriate setting of dwFlags, this function can also create and destroy
key containers.
If dwFlags is set to CRYPT_NEWKEYSET, a new key container is created with the
name specified by pszContainer. If pszContainer is NULL, a key container with the
default name is created.
If dwFlags is set to CRYPT_DELETEKEYSET, The key container specified by
pszContainer is deleted. If pszContainer is NULL, the key container with the default
name is deleted. All key pairs in the key container are also destroyed and memory
is zeroized.
When this flag is set, the value returned in phProv is undefined, and thus, the
CryptReleaseContext function need not be called afterwards.
CryptGetProvParam
The CryptGetProvParam function retrieves data that governs the operations of the
provider. This function may be used to enumerate key containers, enumerate
supported algorithms, and generally determine capabilities of the CSP.
{ TC "SPECIFICATION OF
SERVICES" \F SP
}SPECIFICATION OF
SERVICES
5
CryptSetProvParam
The CryptSetProvParam function customizes various aspects of a provider’s
operations. This function is may be used to set a security descriptor on a key
container.
CryptReleaseContext
The CryptReleaseContext function releases the handle referenced by the hProv
parameter. After a provider handle has been released, it becomes invalid and
cannot be used again. In addition, key and hash handles associated with that
provider handle may not be used after CryptReleaseContext has been called.
Key Generation and Exchange
The following functions provide interfaces to the cryptomodule’s key generation and
exchange functions.
CryptDeriveKey
The CryptDeriveKey function generates cryptographic session keys derived from a
hash value. This function guarantees that when the same CSP and algorithms are
used, the keys generated from the same hash value are identical. The hash value is
typically a cryptographic hash (SHA-1, etc.) of a password or similar secret user
data.
This function is the same as CryptGenKey, except that the generated session keys
are derived from the hash value instead of being random and CryptDeriveKey can
only be used to generate session keys. It cannot generate public/private key pairs.
If keys are being derived from a CALG_SCHANNEL_MASTER_HASH then the
appropriate key derivation process is used to derive the key. In this case the
process used is from either the SSL 2.0, SSL 3.0, PCT or TLS specification of
deriving client and server side encryption and MAC keys. This function will cause
the key block to be derived from the master secret and the requested key is then
derived from the key block. Which process is used is determined by which protocol
is associated with the hash object. For more information see the SSL 2.0, SSL 3.0,
PCT and TLS specifications.
CryptDestroyKey
The CryptDestroyKey function releases the handle referenced by the hKey
parameter. After a key handle has been released, it becomes invalid and cannot be
used again.
6
If the handle refers to a session key, or to a public key that has been imported into
the CSP through CryptImportKey, this function zeroizes the key in memory and
frees the memory that the key occupied. The underlying public/private key pair is
not destroyed by this function. Only the handle is destroyed.
CryptExportKey
The CryptExportKey function exports cryptographic keys from a cryptographic
service provider (CSP) in a secure manner for key archival purposes.
A handle to a private RSA key to be exported may be passed to the function, and
the function returns a key blob. This private key blob can be sent over a nonsecure
transport or stored in a nonsecure storage location. The private key blob is useless
until the intended recipient uses the CryptImportKey function on it to import the key
into the recipient's CSP. Key blobs are exported either in plaintext or encrypted
with a symmetric key. If a symmetric key is used to encrypt the blob then a handle
to the private RSA key is passed in to the module and the symmetric key referenced
by the handle is used to encrypt the blob. Any of the supported symmetric
cryptographic algorithm’s may be used to encrypt the private key blob (DES, RC4 or
RC2).
Public RSA keys are also exported using this function. A handle to the RSA public
key is passed to the function and the public key is exported, always in plaintext as a
blob. This blob may then be imported using the CryptImportKey function.
Symmetric keys may also be exported encrypted with an RSA key using the
CryptExportKey function. A handle to the symmetric key and a handle to the public
RSA key to encrypt with are passed to the function. The function returns a blob
(SIMPLEBLOB) which is the encrypted symmetric key.
Symmetric keys may also be exported by wrapping the keys with another symmetric
key. The wrapped key is then exported as a blob and may be imported using the
CryptImportKey function.
CryptGenKey
The CryptGenKey function generates a random cryptographic key. A handle to the
key is returned in phKey. This handle can then be used as needed with any
CryptoAPI function requiring a key handle.
The calling application must specify the algorithm when calling this function.
Because this algorithm type is kept bundled with the key, the application does not
need to specify the algorithm later when the actual cryptographic operations are
performed.
CryptGenRandom
The CryptGenRandom function fills a buffer with random bytes. The random
number generation algorithm is the SHS based RNG from FIPS 186.
7
CryptGetKeyParam
The CryptGetKeyParam function retrieves data that governs the operations of a
key.
CryptGetUserKey
The CryptGetUserKey function retrieves a handle of one of a user's public/private
key pairs.
CryptImportKey
The CryptImportKey function transfers a cryptographic key from a key blob into a
cryptographic service provider (CSP).
Private keys may be imported as blobs and the function will return a handle to the
imported key.
A symmetric key encrypted with an RSA public key is imported into the
CryptoImportKey function. The function uses the RSA private key exchange key to
decrypt the blob and returns a handle to the symmetric key.
Symmetric keys wrapped with other symmetric keys may also be imported using
this function. The wrapped key blob is passed in along with a handle to a
symmetric key which the module is supposed to use to unwrap the blob. If the
function is successful then a handle to the unwrapped symmetric key is returned.
CryptSetKeyParam
The CryptSetKeyParam function customizes various aspects of a key's operations.
This function is used to set session-specific values for symmetric keys.
CryptDuplicateKey
The CryptDuplicateKey function is used to duplicate, make a copy of, the state of a
key and returns a handle to this new key. The CryptDestroyKey function must be
used on both the handle to the original key and the newly duplicated key.
Data Encryption and Decryption
The following functions provide interfaces to the cryptomodule’s data encryption and
decryption functions.
CryptDecrypt
The CryptDecrypt function decrypts data previously encrypted using CryptEncrypt
function.
8
CryptEncrypt
The CryptEncrypt function encrypts data. The algorithm used to encrypt the data is
designated by the key held by the CSP module and is referenced by the hKey
parameter.
Hashing and Digital Signatures
The following functions provide interfaces to the cryptomodule’s hashing and digital
signature functions.
CryptCreateHash
The CryptCreateHash function initiates the hashing of a stream of data. It returns to
the calling application a handle to a CSP hash object. This handle is used in
subsequent calls to CryptHashData and CryptHashSessionKey in order to hash
streams of data and session keys. SHA-1 and MD5 are the cryptographic hashing
algorithms supported. In addition, a MAC using a symmetric key is created with this
call and may be used with any of the symmetric block ciphers support by the
module (DES, RC4 or RC2).
A CALG_SCHANNEL_MASTER_HASH may be created with this call. If this is the
case then a handle to one of the following types of keys must be passed in the hKey
parameter, CALG_SSL2_MASTER, CALG_SSL3_MASTER,
CALG_PCT1_MASTER, or CALG_TLS1_MASTER. This function with
CALG_SCHANNEL_MASTER_HASH in the ALGID parameter will cause the
derivation of the master secret from the pre-master secret associated with the
passed in key handle. This key derivation process is done in the method specified
in the appropriate protocol specification, SSL 2.0, SSL 3.0, PCT 1.0, or TLS. The
master secret is then associated with the resulting hash handle and session keys
and MAC keys may be derived from this hash handle. The master secret may not
be exported or imported from the module. The key data associated with the hash
handle is zeroized when CryptDestroyHash is called.
CryptDestroyHash
The CryptDestroyHash function destroys the hash object referenced by the hHash
parameter. After a hash object has been destroyed, it can no longer be used.
If the hash handle references a CALG_SCHANNEL_MASTER_HASH key then
when CryptDestroyHash is called the associated key material is zeroized.
All hash objects should be destroyed with the CryptDestroyHash function when the
application is finished with them.
9
CryptGetHashParam
The CryptGetHashParam function retrieves data that governs the operations of a
hash object. The actual hash value can also be retrieved by using this function.
CryptHashData
The CryptHashData function adds data to a specified hash object. This function and
CryptHashSessionKey can be called multiple times to compute the hash on long
data streams or discontinuous data streams. Before calling this function, the
CryptCreateHash function must be called to create a handle of a hash object.
CryptHashSessionKey
The CryptHashSessionKey function computes the cryptographic hash of a key
object. This function can be called multiple times with the same hash handle to
compute the hash of multiple keys. Calls to CryptHashSessionKey can be
interspersed with calls to CryptHashData. Before calling this function, the
CryptCreateHash function must be called to create the handle of a hash object.
CryptSetHashParam
The CryptSetHashParam function customizes the operations of a hash object.
CryptSignHash
The CryptSignHash function signs data. Because all signature algorithms are
asymmetric and thus slow, the CryptoAPI does not allow data be signed directly.
Instead, data is first hashed and CryptSignHash is used to sign the hash. The
crypto module supports signing with RSA. The X9.31 format may be specified by a
flag.
CryptVerifySignature
The CryptVerifySignature function verifies the signature of a hash object. Before
calling this function, the CryptCreateHash function must be called to create the
handle of a hash object. CryptHashData or CryptHashSessionKey is then used to
add data or session keys to the hash object. The crypto module supports verifying
RSA signatures. The X9.31 format may be specified by a flag.
After this function has been completed, only CryptDestroyHash can be called using
the hHash handle.
CryptDuplicateHash
The CryptDuplicateHash function is used to duplicate, make a copy of, the state of a
hash and returns a handle to this new hash. The CryptDestroyHash function must
be used on both the handle to the original hash and the newly duplicated hash.
10
The RSABASE cryptomodule manages keys in the following manner.
Key Material
RSABASE can create and use keys for the following algorithms: RSA Signature,
RSA Key Exchange, RC2, RC4, and DES.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Structures\Cryptography Structures for more
information about key formats and structures.
Key Generation
Random keys can be generated by calling the CryptGenKey() function. Keys can
also be derived from known values via the CryptDeriveKey() function. DES key are
generated and validated following the manner described in FIPS PUB 46-2 and
FIPS PUB 81.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
Key Entry and Output
Keys can be both exported and imported out of and into RSABASE via
CryptExportKey() and CryptImportKey(). Exported private keys may be encrypted
with a symmetric key passed into the CryptExportKey function. Any of the
symmetric algorithms supported by the crypto module may be used to encrypt
private keys for export (DES, RC4 or RC2). When private keys are generated or
imported from archival, they are covered with the Microsoft Windows 2000 Data
Protection API (DPAPI) and then outputted to the file system in the covered form.
Symmetric key entry and output is done by exchanging keys using the recipient’s
asymmetric public key. Symmetric key entry and output may also be done by
exporting a symmetric key wrapped with another symmetric key.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
Key Storage
RSABASE offloads the key storage operations to the Microsoft Windows 2000
operating system. Keys are not stored in the cryptographic module, private keys are
encrypted by the Microsoft Data Protection API (DPAPI) service, and then stored in
the Microsoft Windows 2000 file system. Keys are zeroized from memory after use.
Only the key used for power up self-testing is stored in the cryptographic module.
{ TC "CRYPTOGRAPHIC
KEY MANAGEMENT" \F
SP }CRYPTOGRAPHIC
KEY MANAGEMENT
11
When an Authenticated User requests a keyed cryptographic operation from
RSABASE his/her keys are retrieved from the file system.
DPAPI uses a two-phase algorithm for shrouding the Secret Key (SK) used to
encrypt data. Phase 2 occurs by default only if there is a Domain Controller
associated with the user. Therefore in the local user case, the SK is protected by a
local LSA secret. SYSKEY should be enabled to prevent access to this key. Refer
to NT4/win2k documentation for info on SYSKEY.
Phase 1: Local Agent
In the first phase, the system shrouds the secret locally, relying on the service run
as Local System to protect secrets. This protection shrouds the data both as it
travels on the wire and also blinds the data from the DC. Thus, the shrouding
ensures that no remote user (even a “phase 2” remote recovery agent) can decrypt
the data independent from the local system.
Recovery setup
1. Agent has data D1 to shroud
2. Agent uses secret key SK encrypt D1
3. Agent stores SK in the user hive ACLed to local agent
4. Agent has shrouded E{D1}
Initiate recovery
1. Agent has E{D1} to unshroud
2. Agent retrieves secret key SK from user hive
3. Agent uses secret key SK to decrypt E{D1}
4. Agent has unshrouded D1
Phase 2: Remote Agent
In the second phase, if the machine is networked, the shrouded secret is sent to the
domain controller (DC) for an identification stamp and second shrouding. This
second shrouding will ensure that a roaming user profile is not self-contained, but
needs an interactive logon to successfully recover the master key.
Recovery setup
5. User sends data D2 to remote agent
6. Agent uses secret monster key K, random R2, HMACs to derive SymKeyM.
7. Use SymKeyM to MAC {userid, D2} -> m{userid, D2}
12
8. Agent uses secret monster key K, random R3, HMACs to derive SymKeyK.
9. Use SymKeyK to encrypt { m{userid, D2} , R2 }
10. Agent returns recovery field E{ m{userid, D2}, R2 }, R3 to User
11. User stores recovery field E{ m{userid, D2}, R2 }, R3
Initiate recovery
5. User sends recovery field E{ m{userid, D2}, R2 }, R3 to remote agent
6. Agent uses secret monster key K, HMACs with R3 to re-derive SymKeyK.
7. SymKeyK used to decrypt m{userid, D2}, R2
8. Agent uses secret monster key K, HMACs with R2 to re-derive SymKeyM.
9. SymKeyM used to check MAC on {userid, D2}.
10. Agent returns D2 if userid matches current recovery requestor.
These phases can be nested such that D2 = E{D1}, which allows neither of the
agents to recover the data barring collusion.
Key Archival
RSABASE does not directly archive cryptographic keys. The Authenticated User
may choose to export a cryptographic key labeled as exportable (cf. “Key Input and
Output” above), but management of the secure archival of that key is the
responsibility of the user.
Key Destruction
All keys are destroyed and their memory location zeroized when the Authenticated
User calls CryptDestroyKey on that key handle. Private keys (which are stored by
the operating system in covered format in the protected storage system portion of
the NT4.0 OS) are destroyed when the Authenticated User calls
CryptAcquireContext with the CRYPT_DELETE_KEYSET flag.
13
Mandatory
Software tests via a DES MAC of library image
• RC4 encrypt/decrypt KAT
• RC2 ECB encrypt/decrypt KAT
• DES ECB encrypt/decrypt KAT
• RC2 CBC encrypt/decrypt KAT
• DES CBC encrypt/decrypt KAT
• MD5 hash KAT
• SHA-1 hash KAT
• RSA pairwise consistency test
Conditional
The following are initiated at key generation:
• RSA pairwise consistency test
{ TC "SELF-TESTS" \F SP
}SELF-TESTS
14
The following items address requirements not addressed above.
Cryptographic Bypass
Cryptographic bypass is not support in RSABASE.
Operation Authentication
RSABASE inherits all authentication from the Microsoft Windows 2000 operating
system upon which it runs. Microsoft Windows 2000 requires authentication from a
trusted control base (TCB) before a user is able to access system services. Once a
user is authenticated from the TCB, a process is created bearing the Authenticated
User’s security token. All subsequent processes and threads created by that
Authenticated User are implicitly assigned the parent’s (thus the Authenticated
User’s) security token. Every user that has been authenticated by Microsoft
Windows 2000 is naturally assigned the Authenticated User role when he/she
accesses RSABASE.
Identity-based Authentication
While all Authenticated Users are assigned the same role and thus have access to
the same complete set of services, individual Authenticated Users may only access
key containers which they themselves have created. RSABASE assumes the
authentication of the user and enforces it by running in a thread with the
Authenticated User’s security token.
ModularExpOffload
The ModularExpOffload function offloads modular exponentiation from a CSP to a
hardware accelerator. The CSP will check in the registry for the value
HKLM\Software\Microsoft\Cryptography\ExpoOffload that can be the name of a
DLL. The CSP uses LoadLibrary to load that DLL and calls GetProcAddress to get
the OffloadModExpo entry point in the DLL specified in the registry. The CSP uses
the entry point to perform all modular exponentiations for both public and private
key operations. Two checks are made before a private key is offloaded.
Operating System Security
The RSABASE cryptomodule is intended to run on Windows 2000 in Single User
Mode.
{ TC "MISCELLANEOUS"
\F SP }MISCELLANEOUS
15
When an operating system process loads the cryptomodule into memory, the
cryptomodule runs a DES MAC on the cryptomodule’s disk image of
RSABASE.DLL, excluding the DES MAC, checksum, and export signature
resources. This MAC is compared to the value stored in the DES MAC resource.
Initialization will only succeed if the two values are equal.
Each operating system process creates a unique instance of the cryptomodule that
is wholly dedicated to that process. The cryptomodule is not shared between
processes.
16
For the latest information on Windows NT Server, check out our World Wide Web
site at http://www.microsoft.com/ntserver or the Windows NT Server Forum on the
MSN™ network of Internet services (GO WORD: MSNTS)
{ TC "FOR MORE
INFORMATION" \F SP
}FOR MORE
INFORMATION
17
i
Windows NT®
Operating System
Microsoft Base DSS Cryptographic
Provider
FIPS 140-1 Documentation: Security Policy
September 20, 2000 11:29 AM
Abstract
This document specifies the security policy for the Microsoft Base DSS Cryptographic Provider
(DSSBASE) as described in FIPS PUB 140-1.
®
ii
INTRODUCTION .......................................................................... 1
SECURITY POLICY...................................................................... 2
SPECIFICATION OF ROLES ........................................................ 3
SPECIFICATION OF SERVICES................................................... 4
CRYPTOGRAPHIC KEY MANAGEMENT ..................................... 9
SELF-TESTS .............................................................................. 12
MISCELLANEOUS...................................................................... 13
FOR MORE INFORMATION ....................................................... 14
CONTENTS
1
Microsoft Base DSS Cryptographic Provider (DSSBASE) is a FIPS 140-1 Level 1
compliant, general-purpose, software-based, cryptographic module. Like other
cryptographic providers that ship with Microsoft Windows 2000, DSSBASE
encapsulates several different cryptographic algorithms in an easy-to-use
cryptographic module accessible via the Microsoft CryptoAPI. It can be dynamically
linked into applications by software developers to permit the use of general-purpose
FIPS 140-1 Level 1 compliant cryptography.
Cryptographic Boundary
The Microsoft Base DSS Cryptographic Provider (DSSBASE) consists of a single
dynamically-linked library (DLL) named DSSBASE.DLL. The cryptographic
boundary for DSSBASE is defined as the enclosure of the computer system on
which the cryptographic module is to be executed. The physical configuration of the
module, as defined in FIPS PUB 140-1, is Multi-Chip Standalone.
{ TC "INTRODUCTION" \F
SP }INTRODUCTION
2
DSSBASE operates under several rules that encapsulate its security policy.
• DSSBASE is supported on Windows 2000.
• DSSBASE relies on Microsoft Windows 2000 for the authentication of users.
• DSSBASE enforces a single role, Authenticated User, which is a combination
of the User and Cryptographic Officer roles as defined in FIPS PUB 140-1.
• All users authenticated by Microsoft Windows 2000 employ the Authenticated
User role.
• All services implemented within DSSBASE are available to the Authenticated
User role.
• Keys created within DSSBASE by one user are not accessible to any other
user via DSSBASE.
• DSSBASE stores keys in the file system, but relies on Microsoft Windows 2000
for the covering of the keys prior to storage.
• DSSBASE performs the following self-tests upon power up:
− RC4 encrypt/decrypt
− RC2 ECB encrypt/decrypt
− DES ECB encrypt/decrypt
− DES40 ECB encrypt/decrypt
− RC2 CBC encrypt/decrypt
− DES CBC encrypt/decrypt
− DES40 CBC encrypt/decrypt
− MD5 hash
− SHA-1 hash
• DSSBASE performs a pairwise consistency test upon each invocation of DSA
key generation as defined in FIPS PUB 140-1 and FIPS PUB 186.
{ TC "SECURITY
POLICY" \F SP
}SECURITY POLICY
3
DSSBASE combines the User and Cryptographic Officer roles (as defined in FIPS
PUB 140-1) into a single role hereon called the Authenticated User role. The
Authenticated User may access all services implemented in the cryptographic
module.
An application requests the crypto module to generate keys for a user. Keys are
generated, used and deleted as requested by applications. There are not implicit
keys associated with a user. Each user may have numerous keys, signature and
key exchange, and these keys are separate from other users’ keys.
Maintenance Roles
Maintenance roles are not supported by DSSBASE.
Multiple Concurrent Operators
DSSBASE is intended to run on Windows 2000 in Single User Mode. When run in
this configuration, multiple concurrent operators are not supported.
{ TC "SPECIFICATION OF
ROLES" \F SP
}SPECIFICATION OF
ROLES
4
The following list contains all services available to an operator. All services are
accessible by all Authenticated Users, the one and only role supported by
DSSBASE.
Key Storage
DSSBASE stores keys in the file system. The task of covering the keys prior to
storage in the file system is delegated to the Data Protection API of Microsoft
Windows 2000, a separate component of the operating system, and outside the
boundaries of the cryptomodule. When a key container is deleted, the file is
zeroized before being deleted.
CryptAcquireContext
The CryptAcquireContext function is used to acquire a handle to a particular key
container via a particular cryptographic service provider (CSP). This returned
handle can then be used to make calls to the selected CSP.
This function performs two operations. It first attempts to find a CSP with the
characteristics described in the dwProvType and pszProvider parameters. If the
CSP is found, the function attempts to find a key container matching the name
specified by the pszContainer parameter.
With the appropriate setting of dwFlags, this function can also create and destroy
key containers.
If dwFlags is set to CRYPT_NEWKEYSET, a new key container is created with the
name specified by pszContainer. If pszContainer is NULL, a key container with the
default name is created.
If dwFlags is set to CRYPT_DELETEKEYSET, The key container specified by
pszContainer is deleted. If pszContainer is NULL, the key container with the default
name is deleted. All key pairs in the key container are also destroyed and memory
is zeroized.
When this flag is set, the value returned in phProv is undefined, and thus, the
CryptReleaseContext function need not be called afterwards.
CryptGetProvParam
The CryptGetProvParam function retrieves data that governs the operations of the
provider. This function may be used to enumerate key containers, enumerate
supported algorithms, and generally determine capabilities of the CSP.
{ TC "SPECIFICATION OF
SERVICES" \F SP
}SPECIFICATION OF
SERVICES
5
CryptSetProvParam
The CryptSetProvParam function customizes various aspects of a provider’s
operations. This function is may be used to set a security descriptor on a key
container.
CryptReleaseContext
The CryptReleaseContext function releases the handle referenced by the hProv
parameter. After a provider handle has been released, it becomes invalid and
cannot be used again. In addition, key and hash handles associated with that
provider handle may not be used after CryptReleaseContext has been called.
Key Generation and Exchange
The following functions provide interfaces to the cryptomodule’s key generation and
exchange functions.
CryptDeriveKey
The CryptDeriveKey function generates cryptographic session keys derived from a
hash value. This function guarantees that when the same CSP and algorithms are
used, the keys generated from the same hash value are identical. The hash value is
typically a cryptographic hash (SHA-1, etc.) of a password or similar secret user
data.
This function is the same as CryptGenKey, except that the generated session keys
are derived from the hash value instead of being random and CryptDeriveKey can
only be used to generate session keys. It cannot generate public/private key pairs.
If keys are being derived from a CALG_SCHANNEL_MASTER_HASH then the
appropriate key derivation process is used to derive the key. In this case the
process used is from either the SSL 2.0, SSL 3.0, PCT or TLS specification of
deriving client and server side encryption and MAC keys. This function will cause
the key block to be derived from the master secret and the requested key is then
derived from the key block. Which process is used is determined by which protocol
is associated with the hash object. For more information see the SSL 2.0, SSL 3.0,
PCT and TLS specifications.
CryptDestroyKey
The CryptDestroyKey function releases the handle referenced by the hKey
parameter. After a key handle has been released, it becomes invalid and cannot be
used again.
6
If the handle refers to a session key, or to a public key that has been imported into
the CSP through CryptImportKey, this function zeroizes the key in memory and
frees the memory that the key occupied. The underlying public/private key pair is
not destroyed by this function. Only the handle is destroyed.
CryptExportKey
The CryptExportKey function exports cryptographic keys from a cryptographic
service provider (CSP) in a secure manner for key archival purposes.
A handle to a private DSS/DH key to be exported may be passed to the function,
and the function returns a key blob. This private key blob can be sent over a
nonsecure transport or stored in a nonsecure storage location. The private key blob
is useless until the intended recipient uses the CryptImportKey function on it to
import the key into the recipient's CSP. Key blobs are exported either in plaintext or
encrypted with a symmetric key. If a symmetric key is used to encrypt the blob then
a handle to the private DSS/DH key is passed in to the module and the symmetric
key referenced by the handle is used to encrypt the blob. Any of the supported
symmetric cryptographic algorithm’s may be used to encrypt the private key blob
(DES, DES40, RC4 or RC2).
Public DSS/DH keys are also exported using this function. A handle to the DSS/DH
public key is passed to the function and the public key is exported, always in
plaintext as a blob. This blob may then be imported using the CryptImportKey
function.
Symmetric keys may also be exported by wrapping the keys with another symmetric
key. The wrapped key is then exported as a blob and may be imported using the
CryptImportKey function.
CryptGenKey
The CryptGenKey function generates a random cryptographic key. A handle to the
key is returned in phKey. This handle can then be used as needed with any
CryptoAPI function requiring a key handle.
The calling application must specify the algorithm when calling this function.
Because this algorithm type is kept bundled with the key, the application does not
need to specify the algorithm later when the actual cryptographic operations are
performed.
Generation of a DSS key for signatures requires the operator to complete several
steps before a DSS key is generated. CryptGenKey is first called with
CRYPT_PREGEN set in the dwFlags parameter. The operator then sets the P, Q,
and G for the key generation via CryptSetKeyParam, once for each parameter. The
operator calls CryptSetKeyParam with KP_X set as dwParam to complete the key
generation.
7
CryptGenRandom
The CryptGenRandom function fills a buffer with random bytes. The random
number generation algorithm is the SHS based RNG from FIPS 186.
CryptGetKeyParam
The CryptGetKeyParam function retrieves data that governs the operations of a
key.
CryptGetUserKey
The CryptGetUserKey function retrieves a handle of one of a user's public/private
key pairs.
CryptImportKey
The CryptImportKey function transfers a cryptographic key from a key blob into a
cryptographic service provider (CSP).
Private keys may be imported as blobs and the function will return a handle to the
imported key.
Symmetric keys wrapped with other symmetric keys may also be imported using
this function. The wrapped key blob is passed in along with a handle to a
symmetric key which the module is supposed to use to unwrap the blob. If the
function is successful then a handle to the unwrapped symmetric key is returned.
CryptSetKeyParam
The CryptSetKeyParam function customizes various aspects of a key's operations.
This function is used to set session-specific values for symmetric keys.
CryptDuplicateKey
The CryptDuplicateKey function is used to duplicate, make a copy of, the state of a
key and returns a handle to this new key. The CryptDestroyKey function must be
used on both the handle to the original key and the newly duplicated key.
Data Encryption and Decryption
The following functions provide interfaces to the cryptomodule’s data encryption and
decryption functions.
CryptDecrypt
The CryptDecrypt function decrypts data previously encrypted using CryptEncrypt
function.
8
CryptEncrypt
The CryptEncrypt function encrypts data. The algorithm used to encrypt the data is
designated by the key held by the CSP module and is referenced by the hKey
parameter.
Hashing and Digital Signatures
The following functions provide interfaces to the cryptomodule’s hashing and digital
signature functions.
CryptCreateHash
The CryptCreateHash function initiates the hashing of a stream of data. It returns to
the calling application a handle to a CSP hash object. This handle is used in
subsequent calls to CryptHashData and CryptHashSessionKey in order to hash
streams of data and session keys. SHA-1 and MD5 are the cryptographic hashing
algorithms supported. In addition, a MAC using a symmetric key is created with this
call and may be used with any of the symmetric block ciphers support by the
module (DES, DES40, RC4 or RC2).
A CALG_SCHANNEL_MASTER_HASH may be created with this call. If this is the
case then a handle to one of the following types of keys must be passed in the hKey
parameter, CALG_SSL2_MASTER, CALG_SSL3_MASTER,
CALG_PCT1_MASTER, or CALG_TLS1_MASTER. This function with
CALG_SCHANNEL_MASTER_HASH in the ALGID parameter will cause the
derivation of the master secret from the pre-master secret associated with the
passed in key handle. This key derivation process is done in the method specified
in the appropriate protocol specification, SSL 2.0, SSL 3.0, PCT 1.0, or TLS. The
master secret is then associated with the resulting hash handle and session keys
and MAC keys may be derived from this hash handle. The master secret may not
be exported or imported from the module. The key data associated with the hash
handle is zeroized when CryptDestroyHash is called.
CryptDestroyHash
The CryptDestroyHash function destroys the hash object referenced by the hHash
parameter. After a hash object has been destroyed, it can no longer be used.
If the hash handle references a CALG_SCHANNEL_MASTER_HASH key then
when CryptDestroyHash is called the associated key material is zeroized.
All hash objects should be destroyed with the CryptDestroyHash function when the
application is finished with them.
9
CryptGetHashParam
The CryptGetHashParam function retrieves data that governs the operations of a
hash object. The actual hash value can also be retrieved by using this function.
CryptHashData
The CryptHashData function adds data to a specified hash object. This function and
CryptHashSessionKey can be called multiple times to compute the hash on long
data streams or discontinuous data streams. Before calling this function, the
CryptCreateHash function must be called to create a handle of a hash object.
CryptHashSessionKey
The CryptHashSessionKey function computes the cryptographic hash of a key
object. This function can be called multiple times with the same hash handle to
compute the hash of multiple keys. Calls to CryptHashSessionKey can be
interspersed with calls to CryptHashData. Before calling this function, the
CryptCreateHash function must be called to create the handle of a hash object.
CryptSetHashParam
The CryptSetHashParam function customizes the operations of a hash object.
CryptSignHash
The CryptSignHash function signs data. Because all signature algorithms are
asymmetric and thus slow, the CryptoAPI does not allow data be signed directly.
Instead, data is first hashed and CryptSignHash is used to sign the hash. The
crypto module supports signing with DSS.
CryptVerifySignature
The CryptVerifySignature function verifies the signature of a hash object. Before
calling this function, the CryptCreateHash function must be called to create the
handle of a hash object. CryptHashData or CryptHashSessionKey is then used to
add data or session keys to the hash object. The crypto module supports verifying
DSS signatures.
After this function has been completed, only CryptDestroyHash can be called using
the hHash handle.
CryptDuplicateHash
The CryptDuplicateHash function is used to duplicate, make a copy of, the state of a
hash and returns a handle to this new hash. The CryptDestroyHash function must
be used on both the handle to the original hash and the newly duplicated hash.
10
The DSSBASE cryptomodule manages keys in the following manner.
Key Material
DSSBASE can create and use keys for the following algorithms: DSS, Diffie-
Hellman, RC2, RC4, DES, and DES40.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Structures\Cryptography Structures for more
information about key formats and structures.
Key Generation
Random keys can be generated by calling the CryptGenKey() function. Keys can
also be derived from known values via the CryptDeriveKey() function. DSS keys are
generated and validated following the manner described in FIPS PUB 186-1. DES
key are generated and validated following the manner described in FIPS PUB 46-2
and FIPS PUB 81.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
Key Entry and Output
Keys can be both exported and imported out of and into DSSBASE via
CryptExportKey() and CryptImportKey(). Exported private keys may be encrypted
with a symmetric key passed into the CryptExportKey function. Any of the
symmetric algorithms supported by the crypto module may be used to encrypt
private keys for export (DES, DES40, RC4 or RC2). When private keys are
generated or imported from archival, they are covered with the Microsoft Windows
2000 Data Protection API (DPAPI) and then outputted to the file system in the
covered form.
Symmetric key entry and output is done by exchanging keys using the recipient’s
asymmetric public key. Symmetric key entry and output may also be done by
exporting a symmetric key wrapped with another symmetric key.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
{ TC "CRYPTOGRAPHIC
KEY MANAGEMENT" \F
SP }CRYPTOGRAPHIC
KEY MANAGEMENT
11
Key Storage
DSSBASE offloads the key storage operations to the Microsoft Windows 2000
operating system. Keys are not stored in the cryptographic module, private keys are
encrypted by the Microsoft Data Protection API (DPAPI) service, and then stored in
the Microsoft Windows 2000 file system. Keys are zeroized from memory after use.
Only the key used for power up self-testing is stored in the cryptographic module.
When an Authenticated User requests a keyed cryptographic operation from
DSSBASE his/her keys are retrieved from the file system.
DPAPI uses a two-phase algorithm for shrouding the Secret Key (SK) used to
encrypt data. Phase 2 occurs by default only if there is a Domain Controller
associated with the user. Therefore in the local user case, the SK is protected by a
local LSA secret. SYSKEY should be enabled to prevent access to this key. Refer
to NT4/win2k documentation for info on SYSKEY.
Phase 1: Local Agent
In the first phase, the system shrouds the secret locally, relying on the service run
as Local System to protect secrets. This protection shrouds the data both as it
travels on the wire and also blinds the data from the DC. Thus, the shrouding
ensures that no remote user (even a “phase 2” remote recovery agent) can decrypt
the data independent from the local system.
Recovery setup
1. Agent has data D1 to shroud
2. Agent uses secret key SK encrypt D1
3. Agent stores SK in the user hive ACLed to local agent
4. Agent has shrouded E{D1}
Initiate recovery
1. Agent has E{D1} to unshroud
2. Agent retrieves secret key SK from user hive
3. Agent uses secret key SK to decrypt E{D1}
4. Agent has unshrouded D1
Phase 2: Remote Agent
In the second phase, if the machine is networked, the shrouded secret is sent to the
domain controller (DC) for an identification stamp and second shrouding. This
second shrouding will ensure that a roaming user profile is not self-contained, but
needs an interactive logon to successfully recover the master key.
12
Recovery setup
5. User sends data D2 to remote agent
6. Agent uses secret monster key K, random R2, HMACs to derive SymKeyM.
7. Use SymKeyM to MAC {userid, D2} -> m{userid, D2}
8. Agent uses secret monster key K, random R3, HMACs to derive SymKeyK.
9. Use SymKeyK to encrypt { m{userid, D2} , R2 }
10. Agent returns recovery field E{ m{userid, D2}, R2 }, R3 to User
11. User stores recovery field E{ m{userid, D2}, R2 }, R3
Initiate recovery
5. User sends recovery field E{ m{userid, D2}, R2 }, R3 to remote agent
6. Agent uses secret monster key K, HMACs with R3 to re-derive SymKeyK.
7. SymKeyK used to decrypt m{userid, D2}, R2
8. Agent uses secret monster key K, HMACs with R2 to re-derive SymKeyM.
9. SymKeyM used to check MAC on {userid, D2}.
10. Agent returns D2 if userid matches current recovery requestor.
These phases can be nested such that D2 = E{D1}, which allows neither of the
agents to recover the data barring collusion.
Key Archival
DSSBASE does not directly archive cryptographic keys. The Authenticated User
may choose to export a cryptographic key labeled as exportable (cf. “Key Input and
Output” above), but management of the secure archival of that key is the
responsibility of the user.
Key Destruction
All keys are destroyed and their memory location zeroized when the Authenticated
User calls CryptDestroyKey on that key handle. Private keys (which are stored by
the operating system in covered format in the protected storage system portion of
the NT4.0 OS) are destroyed when the Authenticated User calls
CryptAcquireContext with the CRYPT_DELETE_KEYSET flag.
13
Mandatory
Software tests via a DES MAC of library image
• RC4 encrypt/decrypt KAT
• RC2 ECB encrypt/decrypt KAT
• DES ECB encrypt/decrypt KAT
• DES40 ECB encrypt/decrypt KAT
• RC2 CBC encrypt/decrypt KAT
• DES CBC encrypt/decrypt KAT
• DES40 CBC encrypt/decrypt KAT
• MD5 hash KAT
• SHA-1 hash KAT
• DSS pairwise consistency test
• Diffie-Hellman pairwise consistency test
Conditional
The following are initiated at key generation:
• DSS pairwise consistency test
• Diffie-Hellman pairwise consistency test
{ TC "SELF-TESTS" \F SP
}SELF-TESTS
14
The following items address requirements not addressed above.
Cryptographic Bypass
Cryptographic bypass is not support in DSSBASE.
Operation Authentication
DSSBASE inherits all authentication from the Microsoft Windows 2000 operating
system upon which it runs. Microsoft Windows 2000 requires authentication from a
trusted control base (TCB) before a user is able to access system services. Once a
user is authenticated from the TCB, a process is created bearing the Authenticated
User’s security token. All subsequent processes and threads created by that
Authenticated User are implicitly assigned the parent’s (thus the Authenticated
User’s) security token. Every user that has been authenticated by Microsoft
Windows 2000 is naturally assigned the Authenticated User role when he/she
accesses DSSBASE.
Identity-based Authentication
While all Authenticated Users are assigned the same role and thus have access to
the same complete set of services, individual Authenticated Users may only access
key containers which they themselves have created. DSSBASE assumes the
authentication of the user and enforces it by running in a thread with the
Authenticated User’s security token.
ModularExpOffload
The ModularExpOffload function offloads modular exponentiation from a CSP to a
hardware accelerator. The CSP will check in the registry for the value
HKLM\Software\Microsoft\Cryptography\ExpoOffload that can be the name of a
DLL. The CSP uses LoadLibrary to load that DLL and calls GetProcAddress to get
the OffloadModExpo entry point in the DLL specified in the registry. The CSP uses
the entry point to perform all modular exponentiations for both public and private
key operations. Two checks are made before a private key is offloaded.
Operating System Security
The DSSBASE cryptomodule is intended to run on Windows 2000 in Single User
Mode.
{ TC "MISCELLANEOUS"
\F SP }MISCELLANEOUS
15
When an operating system process loads the cryptomodule into memory, the
cryptomodule runs a DES MAC on the cryptomodule’s disk image of
DSSBASE.DLL, excluding the DES MAC, checksum, and export signature
resources. This MAC is compared to the value stored in the DES MAC resource.
Initialization will only succeed if the two values are equal.
Each operating system process creates a unique instance of the cryptomodule that
is wholly dedicated to that process. The cryptomodule is not shared between
processes.
16
For the latest information on Windows NT Server, check out our World Wide Web
site at http://www.microsoft.com/ntserver or the Windows NT Server Forum on the
MSN™ network of Internet services (GO WORD: MSNTS)
{ TC "FOR MORE
INFORMATION" \F SP
}FOR MORE
INFORMATION
17
i
Windows NT®
Operating System
Microsoft Enhanced Cryptographic
Provider
FIPS 140-1 Documentation: Security Policy
September 20, 2000 11:29 AM
Abstract
This document specifies the security policy for the Microsoft Enhanced Cryptographic Provider
(RSAENH) as described in FIPS PUB 140-1.
®
ii
INTRODUCTION .......................................................................... 1
SECURITY POLICY...................................................................... 2
SPECIFICATION OF ROLES ........................................................ 3
SPECIFICATION OF SERVICES................................................... 4
CRYPTOGRAPHIC KEY MANAGEMENT ..................................... 9
SELF-TESTS .............................................................................. 12
MISCELLANEOUS...................................................................... 13
FOR MORE INFORMATION ....................................................... 14
CONTENTS
1
Microsoft Enhanced Cryptographic Provider (RSAENH) is a FIPS 140-1 Level 1
compliant, general-purpose, software-based, cryptographic module. Like other
cryptographic providers that ship with Microsoft Windows 2000, RSAENH
encapsulates several different cryptographic algorithms in an easy-to-use
cryptographic module accessible via the Microsoft CryptoAPI. It can be dynamically
linked into applications by software developers to permit the use of general-purpose
FIPS 140-1 Level 1 compliant cryptography.
Cryptographic Boundary
The Microsoft Enhanced Cryptographic Provider (RSAENH) consists of a single
dynamically-linked library (DLL) named RSAENH.DLL. The cryptographic boundary
for RSAENH is defined as the enclosure of the computer system on which the
cryptographic module is to be executed. The physical configuration of the module,
as defined in FIPS PUB 140-1, is Multi-Chip Standalone.
{ TC "INTRODUCTION" \F
SP }INTRODUCTION
2
RSAENH operates under several rules that encapsulate its security policy.
• RSAENH is supported on Windows 2000.
• RSAENH relies on Microsoft Windows 2000 for the authentication of users.
• RSAENH enforces a single role, Authenticated User, which is a combination of
the User and Cryptographic Officer roles as defined in FIPS PUB 140-1.
• All users authenticated by Microsoft Windows 2000 employ the Authenticated
User role.
• All services implemented within RSAENH are available to the Authenticated
User role.
• Keys created within RSAENH by one user are not accessible to any other user
via RSAENH.
• RSAENH stores keys in the file system, but relies on Microsoft Windows 2000
for the covering of the keys prior to storage.
• RSAENH performs the following self-tests upon power up:
− RC4 encrypt/decrypt
− RC2 ECB encrypt/decrypt
− RC2 CBC encrypt/decrypt
− DES ECB encrypt/decrypt
− DES CBC encrypt/decrypt
− DES40 ECB encrypt/decrypt
− 3DES 112 CBC encrypt/decrypt
− 3DES 112 ECB encrypt/decrypt
− 3DES CBC encrypt/decrypt
− 3DES ECB encrypt/decrypt
− MD5 hash
− SHA-1 hash
• RSAENH performs a pairwise consistency test upon each invocation of RSA
key generation as defined in FIPS PUB 140-1.
{ TC "SECURITY
POLICY" \F SP
}SECURITY POLICY
3
RSAENH combines the User and Cryptographic Officer roles (as defined in FIPS
PUB 140-1) into a single role hereon called the Authenticated User role. The
Authenticated User may access all services implemented in the cryptographic
module.
An application requests the crypto module to generate keys for a user. Keys are
generated, used and deleted as requested by applications. There are not implicit
keys associated with a user. Each user may have numerous keys, signature and
key exchange, and these keys are separate from other users’ keys.
Maintenance Roles
Maintenance roles are not supported by RSAENH.
Multiple Concurrent Operators
RSAENH is intended to run on Windows 2000 in Single User Mode. When run in
this configuration, multiple concurrent operators are not supported.
{ TC "SPECIFICATION OF
ROLES" \F SP
}SPECIFICATION OF
ROLES
4
The following list contains all services available to an operator. All services are
accessible by all Authenticated Users, the one and only role supported by
RSAENH.
Key Storage
RSAENH stores keys in the file system. The task of covering the keys prior to
storage in the file system is delegated to the Data Protection API of Microsoft
Windows 2000, a separate component of the operating system, and outside the
boundaries of the cryptomodule. When a key container is deleted, the file is
zeroized before being deleted.
CryptAcquireContext
The CryptAcquireContext function is used to acquire a handle to a particular key
container via a particular cryptographic service provider (CSP). This returned
handle can then be used to make calls to the selected CSP.
This function performs two operations. It first attempts to find a CSP with the
characteristics described in the dwProvType and pszProvider parameters. If the
CSP is found, the function attempts to find a key container matching the name
specified by the pszContainer parameter.
With the appropriate setting of dwFlags, this function can also create and destroy
key containers.
If dwFlags is set to CRYPT_NEWKEYSET, a new key container is created with the
name specified by pszContainer. If pszContainer is NULL, a key container with the
default name is created.
If dwFlags is set to CRYPT_DELETEKEYSET, The key container specified by
pszContainer is deleted. If pszContainer is NULL, the key container with the default
name is deleted. All key pairs in the key container are also destroyed and memory
is zeroized.
When this flag is set, the value returned in phProv is undefined, and thus, the
CryptReleaseContext function need not be called afterwards.
CryptGetProvParam
The CryptGetProvParam function retrieves data that governs the operations of the
provider. This function may be used to enumerate key containers, enumerate
supported algorithms, and generally determine capabilities of the CSP.
{ TC "SPECIFICATION OF
SERVICES" \F SP
}SPECIFICATION OF
SERVICES
5
CryptSetProvParam
The CryptSetProvParam function customizes various aspects of a provider’s
operations. This function is may be used to set a security descriptor on a key
container.
CryptReleaseContext
The CryptReleaseContext function releases the handle referenced by the hProv
parameter. After a provider handle has been released, it becomes invalid and
cannot be used again. In addition, key and hash handles associated with that
provider handle may not be used after CryptReleaseContext has been called.
Key Generation and Exchange
The following functions provide interfaces to the cryptomodule’s key generation and
exchange functions.
CryptDeriveKey
The CryptDeriveKey function generates cryptographic session keys derived from a
hash value. This function guarantees that when the same CSP and algorithms are
used, the keys generated from the same hash value are identical. The hash value is
typically a cryptographic hash (SHA-1, etc.) of a password or similar secret user
data.
This function is the same as CryptGenKey, except that the generated session keys
are derived from the hash value instead of being random and CryptDeriveKey can
only be used to generate session keys. It cannot generate public/private key pairs.
If keys are being derived from a CALG_SCHANNEL_MASTER_HASH then the
appropriate key derivation process is used to derive the key. In this case the
process used is from either the SSL 2.0, SSL 3.0, PCT or TLS specification of
deriving client and server side encryption and MAC keys. This function will cause
the key block to be derived from the master secret and the requested key is then
derived from the key block. Which process is used is determined by which protocol
is associated with the hash object. For more information see the SSL 2.0, SSL 3.0,
PCT and TLS specifications.
CryptDestroyKey
The CryptDestroyKey function releases the handle referenced by the hKey
parameter. After a key handle has been released, it becomes invalid and cannot be
used again.
6
If the handle refers to a session key, or to a public key that has been imported into
the CSP through CryptImportKey, this function zeroizes the key in memory and
frees the memory that the key occupied. The underlying public/private key pair is
not destroyed by this function. Only the handle is destroyed.
CryptExportKey
The CryptExportKey function exports cryptographic keys from a cryptographic
service provider (CSP) in a secure manner for key archival purposes.
A handle to a private RSA key to be exported may be passed to the function, and
the function returns a key blob. This private key blob can be sent over a nonsecure
transport or stored in a nonsecure storage location. The private key blob is useless
until the intended recipient uses the CryptImportKey function on it to import the key
into the recipient's CSP. Key blobs are exported either in plaintext or encrypted
with a symmetric key. If a symmetric key is used to encrypt the blob then a handle
to the private RSA key is passed in to the module and the symmetric key referenced
by the handle is used to encrypt the blob. Any of the supported symmetric
cryptographic algorithm’s may be used to encrypt the private key blob (DES, 3DES,
RC4 or RC2).
Public RSA keys are also exported using this function. A handle to the RSA public
key is passed to the function and the public key is exported, always in plaintext as a
blob. This blob may then be imported using the CryptImportKey function.
Symmetric keys may also be exported encrypted with an RSA key using the
CryptExportKey function. A handle to the symmetric key and a handle to the public
RSA key to encrypt with are passed to the function. The function returns a blob
(SIMPLEBLOB) which is the encrypted symmetric key.
Symmetric keys may also be exported by wrapping the keys with another symmetric
key. The wrapped key is then exported as a blob and may be imported using the
CryptImportKey function.
CryptGenKey
The CryptGenKey function generates a random cryptographic key. A handle to the
key is returned in phKey. This handle can then be used as needed with any
CryptoAPI function requiring a key handle.
The calling application must specify the algorithm when calling this function.
Because this algorithm type is kept bundled with the key, the application does not
need to specify the algorithm later when the actual cryptographic operations are
performed.
CryptGenRandom
The CryptGenRandom function fills a buffer with random bytes. The random
number generation algorithm is the SHS based RNG from FIPS 186.
7
CryptGetKeyParam
The CryptGetKeyParam function retrieves data that governs the operations of a
key.
CryptGetUserKey
The CryptGetUserKey function retrieves a handle of one of a user's public/private
key pairs.
CryptImportKey
The CryptImportKey function transfers a cryptographic key from a key blob into a
cryptographic service provider (CSP).
Private keys may be imported as blobs and the function will return a handle to the
imported key.
A symmetric key encrypted with an RSA public key is imported into the
CryptoImportKey function. The function uses the RSA private key exchange key to
decrypt the blob and returns a handle to the symmetric key.
Symmetric keys wrapped with other symmetric keys may also be imported using
this function. The wrapped key blob is passed in along with a handle to a
symmetric key which the module is supposed to use to unwrap the blob. If the
function is successful then a handle to the unwrapped symmetric key is returned.
CryptSetKeyParam
The CryptSetKeyParam function customizes various aspects of a key's operations.
This function is used to set session-specific values for symmetric keys.
CryptDuplicateKey
The CryptDuplicateKey function is used to duplicate, make a copy of, the state of a
key and returns a handle to this new key. The CryptDestroyKey function must be
used on both the handle to the original key and the newly duplicated key.
Data Encryption and Decryption
The following functions provide interfaces to the cryptomodule’s data encryption and
decryption functions.
CryptDecrypt
The CryptDecrypt function decrypts data previously encrypted using CryptEncrypt
function.
8
CryptEncrypt
The CryptEncrypt function encrypts data. The algorithm used to encrypt the data is
designated by the key held by the CSP module and is referenced by the hKey
parameter.
Hashing and Digital Signatures
The following functions provide interfaces to the cryptomodule’s hashing and digital
signature functions.
CryptCreateHash
The CryptCreateHash function initiates the hashing of a stream of data. It returns to
the calling application a handle to a CSP hash object. This handle is used in
subsequent calls to CryptHashData and CryptHashSessionKey in order to hash
streams of data and session keys. SHA-1 and MD5 are the cryptographic hashing
algorithms supported. In addition, a MAC using a symmetric key is created with this
call and may be used with any of the symmetric block ciphers support by the
module (DES, 3DES, RC4 or RC2).
A CALG_SCHANNEL_MASTER_HASH may be created with this call. If this is the
case then a handle to one of the following types of keys must be passed in the hKey
parameter, CALG_SSL2_MASTER, CALG_SSL3_MASTER,
CALG_PCT1_MASTER, or CALG_TLS1_MASTER. This function with
CALG_SCHANNEL_MASTER_HASH in the ALGID parameter will cause the
derivation of the master secret from the pre-master secret associated with the
passed in key handle. This key derivation process is done in the method specified
in the appropriate protocol specification, SSL 2.0, SSL 3.0, PCT 1.0, or TLS. The
master secret is then associated with the resulting hash handle and session keys
and MAC keys may be derived from this hash handle. The master secret may not
be exported or imported from the module. The key data associated with the hash
handle is zeroized when CryptDestroyHash is called.
CryptDestroyHash
The CryptDestroyHash function destroys the hash object referenced by the hHash
parameter. After a hash object has been destroyed, it can no longer be used.
If the hash handle references a CALG_SCHANNEL_MASTER_HASH key then
when CryptDestroyHash is called the associated key material is zeroized.
All hash objects should be destroyed with the CryptDestroyHash function when the
application is finished with them.
9
CryptGetHashParam
The CryptGetHashParam function retrieves data that governs the operations of a
hash object. The actual hash value can also be retrieved by using this function.
CryptHashData
The CryptHashData function adds data to a specified hash object. This function and
CryptHashSessionKey can be called multiple times to compute the hash on long
data streams or discontinuous data streams. Before calling this function, the
CryptCreateHash function must be called to create a handle of a hash object.
CryptHashSessionKey
The CryptHashSessionKey function computes the cryptographic hash of a key
object. This function can be called multiple times with the same hash handle to
compute the hash of multiple keys. Calls to CryptHashSessionKey can be
interspersed with calls to CryptHashData. Before calling this function, the
CryptCreateHash function must be called to create the handle of a hash object.
CryptSetHashParam
The CryptSetHashParam function customizes the operations of a hash object.
CryptSignHash
The CryptSignHash function signs data. Because all signature algorithms are
asymmetric and thus slow, the CryptoAPI does not allow data be signed directly.
Instead, data is first hashed and CryptSignHash is used to sign the hash. The
crypto module supports signing with RSA. The X9.31 format may be specified by a
flag.
CryptVerifySignature
The CryptVerifySignature function verifies the signature of a hash object. Before
calling this function, the CryptCreateHash function must be called to create the
handle of a hash object. CryptHashData or CryptHashSessionKey is then used to
add data or session keys to the hash object. The crypto module supports verifying
RSA signatures. The X9.31 format may be specified by a flag.
After this function has been completed, only CryptDestroyHash can be called using
the hHash handle.
CryptDuplicateHash
The CryptDuplicateHash function is used to duplicate, make a copy of, the state of a
hash and returns a handle to this new hash. The CryptDestroyHash function must
be used on both the handle to the original hash and the newly duplicated hash.
10
The RSAENH cryptomodule manages keys in the following manner.
Key Material
RSAENH can create and use keys for the following algorithms: RSA Signature,
RSA Key Exchange, RC2, RC4, DES, and 3DES.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Structures\Cryptography Structures for more
information about key formats and structures.
Key Generation
Random keys can be generated by calling the CryptGenKey() function. Keys can
also be derived from known values via the CryptDeriveKey() function. DES key are
generated and validated following the manner described in FIPS PUB 46-2 and
FIPS PUB 81.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
Key Entry and Output
Keys can be both exported and imported out of and into RSAENH via
CryptExportKey() and CryptImportKey(). Exported private keys may be encrypted
with a symmetric key passed into the CryptExportKey function. Any of the
symmetric algorithms supported by the crypto module may be used to encrypt
private keys for export (DES, 3DES, RC4 or RC2). When private keys are
generated or imported from archival, they are covered with the Microsoft Windows
2000 Data Protection API (DPAPI) and then outputted to the file system in the
covered form.
Symmetric key entry and output is done by exchanging keys using the recipient’s
asymmetric public key. Symmetric key entry and output may also be done by
exporting a symmetric key wrapped with another symmetric key.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
{ TC "CRYPTOGRAPHIC
KEY MANAGEMENT" \F
SP }CRYPTOGRAPHIC
KEY MANAGEMENT
11
Key Storage
RSAENH offloads the key storage operations to the Microsoft Windows 2000
operating system. Keys are not stored in the cryptographic module, private keys are
encrypted by the Microsoft Data Protection API (DPAPI) service, and then stored in
the Microsoft Windows 2000 file system. Keys are zeroized from memory after use.
Only the key used for power up self-testing is stored in the cryptographic module.
When an Authenticated User requests a keyed cryptographic operation from
RSAENH his/her keys are retrieved from the file system.
DPAPI uses a two-phase algorithm for shrouding the Secret Key (SK) used to
encrypt data. Phase 2 occurs by default only if there is a Domain Controller
associated with the user. Therefore in the local user case, the SK is protected by a
local LSA secret. SYSKEY should be enabled to prevent access to this key. Refer
to NT4/win2k documentation for info on SYSKEY.
Phase 1: Local Agent
In the first phase, the system shrouds the secret locally, relying on the service run
as Local System to protect secrets. This protection shrouds the data both as it
travels on the wire and also blinds the data from the DC. Thus, the shrouding
ensures that no remote user (even a “phase 2” remote recovery agent) can decrypt
the data independent from the local system.
Recovery setup
1. Agent has data D1 to shroud
2. Agent uses secret key SK encrypt D1
3. Agent stores SK in the user hive ACLed to local agent
4. Agent has shrouded E{D1}
Initiate recovery
1. Agent has E{D1} to unshroud
2. Agent retrieves secret key SK from user hive
3. Agent uses secret key SK to decrypt E{D1}
4. Agent has unshrouded D1
Phase 2: Remote Agent
In the second phase, if the machine is networked, the shrouded secret is sent to the
domain controller (DC) for an identification stamp and second shrouding. This
second shrouding will ensure that a roaming user profile is not self-contained, but
needs an interactive logon to successfully recover the master key.
12
Recovery setup
5. User sends data D2 to remote agent
6. Agent uses secret monster key K, random R2, HMACs to derive SymKeyM.
7. Use SymKeyM to MAC {userid, D2} -> m{userid, D2}
8. Agent uses secret monster key K, random R3, HMACs to derive SymKeyK.
9. Use SymKeyK to encrypt { m{userid, D2} , R2 }
10. Agent returns recovery field E{ m{userid, D2}, R2 }, R3 to User
11. User stores recovery field E{ m{userid, D2}, R2 }, R3
Initiate recovery
5. User sends recovery field E{ m{userid, D2}, R2 }, R3 to remote agent
6. Agent uses secret monster key K, HMACs with R3 to re-derive SymKeyK.
7. SymKeyK used to decrypt m{userid, D2}, R2
8. Agent uses secret monster key K, HMACs with R2 to re-derive SymKeyM.
9. SymKeyM used to check MAC on {userid, D2}.
10. Agent returns D2 if userid matches current recovery requestor.
These phases can be nested such that D2 = E{D1}, which allows neither of the
agents to recover the data barring collusion.
Key Archival
RSAENH does not directly archive cryptographic keys. The Authenticated User may
choose to export a cryptographic key labeled as exportable (cf. “Key Input and
Output” above), but management of the secure archival of that key is the
responsibility of the user.
Key Destruction
All keys are destroyed and their memory location zeroized when the Authenticated
User calls CryptDestroyKey on that key handle. Private keys (which are stored by
the operating system in covered format in the protected storage system portion of
the NT4.0 OS) are destroyed when the Authenticated User calls
CryptAcquireContext with the CRYPT_DELETE_KEYSET flag.
13
Mandatory
Software tests via a DES MAC of library image
• RC4 encrypt/decrypt KAT
• RC2 ECB encrypt/decrypt KAT
• DES ECB encrypt/decrypt KAT
• 3DES ECB encrypt/decrypt KAT
• 3DES 112 ECB encrypt/decrypt KAT
• RC2 CBC encrypt/decrypt KAT
• DES CBC encrypt/decrypt KAT
• 3DES CBC encrypt/decrypt KAT
• 3DES 112 CBC encrypt/decrypt KAT
• MD5 hash KAT
• SHA-1 hash KAT
• RSA pairwise consistency test
Conditional
The following are initiated at key generation:
• RSA pairwise consistency test
{ TC "SELF-TESTS" \F SP
}SELF-TESTS
14
The following items address requirements not addressed above.
Cryptographic Bypass
Cryptographic bypass is not support in RSAENH.
Operation Authentication
RSAENH inherits all authentication from the Microsoft Windows 2000 operating
system upon which it runs. Microsoft Windows 2000 requires authentication from a
trusted control base (TCB) before a user is able to access system services. Once a
user is authenticated from the TCB, a process is created bearing the Authenticated
User’s security token. All subsequent processes and threads created by that
Authenticated User are implicitly assigned the parent’s (thus the Authenticated
User’s) security token. Every user that has been authenticated by Microsoft
Windows 2000 is naturally assigned the Authenticated User role when he/she
accesses RSAENH.
Identity-based Authentication
While all Authenticated Users are assigned the same role and thus have access to
the same complete set of services, individual Authenticated Users may only access
key containers which they themselves have created. RSAENH assumes the
authentication of the user and enforces it by running in a thread with the
Authenticated User’s security token.
ModularExpOffload
The ModularExpOffload function offloads modular exponentiation from a CSP to a
hardware accelerator. The CSP will check in the registry for the value
HKLM\Software\Microsoft\Cryptography\ExpoOffload that can be the name of a
DLL. The CSP uses LoadLibrary to load that DLL and calls GetProcAddress to get
the OffloadModExpo entry point in the DLL specified in the registry. The CSP uses
the entry point to perform all modular exponentiations for both public and private
key operations. Two checks are made before a private key is offloaded.
Operating System Security
The RSAENH cryptomodule is intended to run on Windows 2000 in Single User
Mode.
{ TC "MISCELLANEOUS"
\F SP }MISCELLANEOUS
15
When an operating system process loads the cryptomodule into memory, the
cryptomodule runs a DES MAC on the cryptomodule’s disk image of RSAENH.DLL,
excluding the DES MAC, checksum, and export signature resources. This MAC is
compared to the value stored in the DES MAC resource. Initialization will only
succeed if the two values are equal.
Each operating system process creates a unique instance of the cryptomodule that
is wholly dedicated to that process. The cryptomodule is not shared between
processes.
16
For the latest information on Windows NT Server, check out our World Wide Web
site at http://www.microsoft.com/ntserver or the Windows NT Server Forum on the
MSN™ network of Internet services (GO WORD: MSNTS)
{ TC "FOR MORE
INFORMATION" \F SP
}FOR MORE
INFORMATION
17
i
Windows NT®
Operating System
Microsoft DSS/Diffie-Hellman
Enhanced Cryptographic Provider
FIPS 140-1 Documentation: Security Policy
September 20, 2000 11:29 AM
Abstract
This document specifies the security policy for the Microsoft DSS/Diffie-Hellman Enhanced
Cryptographic Provider (DSSENH) as described in FIPS PUB 140-1.
®
ii
INTRODUCTION .......................................................................... 1
SECURITY POLICY...................................................................... 2
SPECIFICATION OF ROLES ........................................................ 3
SPECIFICATION OF SERVICES................................................... 4
CRYPTOGRAPHIC KEY MANAGEMENT ..................................... 9
SELF-TESTS .............................................................................. 12
MISCELLANEOUS...................................................................... 13
FOR MORE INFORMATION ....................................................... 14
CONTENTS
1
Microsoft DSS/Diffie-Hellman Enhanced Cryptographic Provider (DSSENH) is a
FIPS 140-1 Level 1 compliant, general-purpose, software-based, cryptographic
module. Like other cryptographic providers that ship with Microsoft Windows 2000,
DSSENH encapsulates several different cryptographic algorithms in an easy-to-use
cryptographic module accessible via the Microsoft CryptoAPI. It can be dynamically
linked into applications by software developers to permit the use of general-purpose
FIPS 140-1 Level 1 compliant cryptography.
Cryptographic Boundary
The Microsoft DSS/Diffie-Hellman Enhanced Cryptographic Provider (DSSENH)
consists of a single dynamically-linked library (DLL) named DSSENH.DLL. The
cryptographic boundary for DSSENH is defined as the enclosure of the computer
system on which the cryptographic module is to be executed. The physical
configuration of the module, as defined in FIPS PUB 140-1, is Multi-Chip
Standalone.
{ TC "INTRODUCTION" \F
SP }INTRODUCTION
2
DSSENH operates under several rules that encapsulate its security policy.
• DSSENH is supported on Windows 2000.
• DSSENH relies on Microsoft Windows 2000 for the authentication of users.
• DSSENH enforces a single role, Authenticated User, which is a combination of
the User and Cryptographic Officer roles as defined in FIPS PUB 140-1.
• All users authenticated by Microsoft Windows 2000 employ the Authenticated
User role.
• All services implemented within DSSENH are available to the Authenticated
User role.
• Keys created within DSSENH by one user are not accessible to any other user
via DSSENH.
• DSSENH stores keys in the file system, but relies on Microsoft Windows 2000
for the covering of the keys prior to storage.
• DSSENH performs the following self-tests upon power up:
− RC4 encrypt/decrypt
− RC2 ECB encrypt/decrypt
− DES ECB encrypt/decrypt
− DES40 ECB encrypt/decrypt
− 3DES 112 ECB encrypt/decrypt
− 3DES ECB encrypt/decrypt
− RC2 CBC encrypt/decrypt
− DES CBC encrypt/decrypt
− DES40 CBC encrypt/decrypt
− 3DES 112 CBC encrypt/decrypt
− 3DES CBC encrypt/decrypt
− MD5 hash
− SHA-1 hash
• DSSENH performs a pairwise consistency test upon each invocation of DSA
key generation as defined in FIPS PUB 140-1 and FIPS PUB 186.
{ TC "SECURITY
POLICY" \F SP
}SECURITY POLICY
3
DSSENH combines the User and Cryptographic Officer roles (as defined in FIPS
PUB 140-1) into a single role hereon called the Authenticated User role. The
Authenticated User may access all services implemented in the cryptographic
module.
An application requests the crypto module to generate keys for a user. Keys are
generated, used and deleted as requested by applications. There are not implicit
keys associated with a user. Each user may have numerous keys, signature and
key exchange, and these keys are separate from other users’ keys.
Maintenance Roles
Maintenance roles are not supported by DSSENH.
Multiple Concurrent Operators
DSSENH is intended to run on Windows 2000 in Single User Mode. When run in
this configuration, multiple concurrent operators are not supported.
{ TC "SPECIFICATION OF
ROLES" \F SP
}SPECIFICATION OF
ROLES
4
The following list contains all services available to an operator. All services are
accessible by all Authenticated Users, the one and only role supported by
DSSENH.
Key Storage
DSSENH stores keys in the file system. The task of covering the keys prior to
storage in the file system is delegated to the Data Protection API of Microsoft
Windows 2000, a separate component of the operating system, and outside the
boundaries of the cryptomodule. When a key container is deleted, the file is
zeroized before being deleted.
CryptAcquireContext
The CryptAcquireContext function is used to acquire a handle to a particular key
container via a particular cryptographic service provider (CSP). This returned
handle can then be used to make calls to the selected CSP.
This function performs two operations. It first attempts to find a CSP with the
characteristics described in the dwProvType and pszProvider parameters. If the
CSP is found, the function attempts to find a key container matching the name
specified by the pszContainer parameter.
With the appropriate setting of dwFlags, this function can also create and destroy
key containers.
If dwFlags is set to CRYPT_NEWKEYSET, a new key container is created with the
name specified by pszContainer. If pszContainer is NULL, a key container with the
default name is created.
If dwFlags is set to CRYPT_DELETEKEYSET, The key container specified by
pszContainer is deleted. If pszContainer is NULL, the key container with the default
name is deleted. All key pairs in the key container are also destroyed and memory
is zeroized.
When this flag is set, the value returned in phProv is undefined, and thus, the
CryptReleaseContext function need not be called afterwards.
CryptGetProvParam
The CryptGetProvParam function retrieves data that governs the operations of the
provider. This function may be used to enumerate key containers, enumerate
supported algorithms, and generally determine capabilities of the CSP.
{ TC "SPECIFICATION OF
SERVICES" \F SP
}SPECIFICATION OF
SERVICES
5
CryptSetProvParam
The CryptSetProvParam function customizes various aspects of a provider’s
operations. This function is may be used to set a security descriptor on a key
container.
CryptReleaseContext
The CryptReleaseContext function releases the handle referenced by the hProv
parameter. After a provider handle has been released, it becomes invalid and
cannot be used again. In addition, key and hash handles associated with that
provider handle may not be used after CryptReleaseContext has been called.
Key Generation and Exchange
The following functions provide interfaces to the cryptomodule’s key generation and
exchange functions.
CryptDeriveKey
The CryptDeriveKey function generates cryptographic session keys derived from a
hash value. This function guarantees that when the same CSP and algorithms are
used, the keys generated from the same hash value are identical. The hash value is
typically a cryptographic hash (SHA-1, etc.) of a password or similar secret user
data.
This function is the same as CryptGenKey, except that the generated session keys
are derived from the hash value instead of being random and CryptDeriveKey can
only be used to generate session keys. It cannot generate public/private key pairs.
If keys are being derived from a CALG_SCHANNEL_MASTER_HASH then the
appropriate key derivation process is used to derive the key. In this case the
process used is from either the SSL 2.0, SSL 3.0, PCT or TLS specification of
deriving client and server side encryption and MAC keys. This function will cause
the key block to be derived from the master secret and the requested key is then
derived from the key block. Which process is used is determined by which protocol
is associated with the hash object. For more information see the SSL 2.0, SSL 3.0,
PCT and TLS specifications.
CryptDestroyKey
The CryptDestroyKey function releases the handle referenced by the hKey
parameter. After a key handle has been released, it becomes invalid and cannot be
used again.
6
If the handle refers to a session key, or to a public key that has been imported into
the CSP through CryptImportKey, this function zeroizes the key in memory and
frees the memory that the key occupied. The underlying public/private key pair is
not destroyed by this function. Only the handle is destroyed.
CryptExportKey
The CryptExportKey function exports cryptographic keys from a cryptographic
service provider (CSP) in a secure manner for key archival purposes.
A handle to a private DSS/DH key to be exported may be passed to the function,
and the function returns a key blob. This private key blob can be sent over a
nonsecure transport or stored in a nonsecure storage location. The private key blob
is useless until the intended recipient uses the CryptImportKey function on it to
import the key into the recipient's CSP. Key blobs are exported either in plaintext or
encrypted with a symmetric key. If a symmetric key is used to encrypt the blob then
a handle to the private DSS/DH key is passed in to the module and the symmetric
key referenced by the handle is used to encrypt the blob. Any of the supported
symmetric cryptographic algorithm’s may be used to encrypt the private key blob
(DES, 3DES, DES40, RC4 or RC2).
Public DSS/DH keys are also exported using this function. A handle to the DSS/DH
public key is passed to the function and the public key is exported, always in
plaintext as a blob. This blob may then be imported using the CryptImportKey
function.
Symmetric keys may also be exported by wrapping the keys with another symmetric
key. The wrapped key is then exported as a blob and may be imported using the
CryptImportKey function.
CryptGenKey
The CryptGenKey function generates a random cryptographic key. A handle to the
key is returned in phKey. This handle can then be used as needed with any
CryptoAPI function requiring a key handle.
The calling application must specify the algorithm when calling this function.
Because this algorithm type is kept bundled with the key, the application does not
need to specify the algorithm later when the actual cryptographic operations are
performed.
Generation of a DSS key for signatures requires the operator to complete several
steps before a DSS key is generated. CryptGenKey is first called with
CRYPT_PREGEN set in the dwFlags parameter. The operator then sets the P, Q,
and G for the key generation via CryptSetKeyParam, once for each parameter. The
operator calls CryptSetKeyParam with KP_X set as dwParam to complete the key
generation.
7
CryptGenRandom
The CryptGenRandom function fills a buffer with random bytes. The random
number generation algorithm is the SHS based RNG from FIPS 186.
CryptGetKeyParam
The CryptGetKeyParam function retrieves data that governs the operations of a
key.
CryptGetUserKey
The CryptGetUserKey function retrieves a handle of one of a user's public/private
key pairs.
CryptImportKey
The CryptImportKey function transfers a cryptographic key from a key blob into a
cryptographic service provider (CSP).
Private keys may be imported as blobs and the function will return a handle to the
imported key.
Symmetric keys wrapped with other symmetric keys may also be imported using
this function. The wrapped key blob is passed in along with a handle to a
symmetric key which the module is supposed to use to unwrap the blob. If the
function is successful then a handle to the unwrapped symmetric key is returned.
CryptSetKeyParam
The CryptSetKeyParam function customizes various aspects of a key's operations.
This function is used to set session-specific values for symmetric keys.
CryptDuplicateKey
The CryptDuplicateKey function is used to duplicate, make a copy of, the state of a
key and returns a handle to this new key. The CryptDestroyKey function must be
used on both the handle to the original key and the newly duplicated key.
Data Encryption and Decryption
The following functions provide interfaces to the cryptomodule’s data encryption and
decryption functions.
CryptDecrypt
The CryptDecrypt function decrypts data previously encrypted using CryptEncrypt
function.
8
CryptEncrypt
The CryptEncrypt function encrypts data. The algorithm used to encrypt the data is
designated by the key held by the CSP module and is referenced by the hKey
parameter.
Hashing and Digital Signatures
The following functions provide interfaces to the cryptomodule’s hashing and digital
signature functions.
CryptCreateHash
The CryptCreateHash function initiates the hashing of a stream of data. It returns to
the calling application a handle to a CSP hash object. This handle is used in
subsequent calls to CryptHashData and CryptHashSessionKey in order to hash
streams of data and session keys. SHA-1 and MD5 are the cryptographic hashing
algorithms supported. In addition, a MAC using a symmetric key is created with this
call and may be used with any of the symmetric block ciphers support by the
module (DES, 3DES, DES40, RC4 or RC2).
A CALG_SCHANNEL_MASTER_HASH may be created with this call. If this is the
case then a handle to one of the following types of keys must be passed in the hKey
parameter, CALG_SSL2_MASTER, CALG_SSL3_MASTER,
CALG_PCT1_MASTER, or CALG_TLS1_MASTER. This function with
CALG_SCHANNEL_MASTER_HASH in the ALGID parameter will cause the
derivation of the master secret from the pre-master secret associated with the
passed in key handle. This key derivation process is done in the method specified
in the appropriate protocol specification, SSL 2.0, SSL 3.0, PCT 1.0, or TLS. The
master secret is then associated with the resulting hash handle and session keys
and MAC keys may be derived from this hash handle. The master secret may not
be exported or imported from the module. The key data associated with the hash
handle is zeroized when CryptDestroyHash is called.
CryptDestroyHash
The CryptDestroyHash function destroys the hash object referenced by the hHash
parameter. After a hash object has been destroyed, it can no longer be used.
If the hash handle references a CALG_SCHANNEL_MASTER_HASH key then
when CryptDestroyHash is called the associated key material is zeroized.
All hash objects should be destroyed with the CryptDestroyHash function when the
application is finished with them.
9
CryptGetHashParam
The CryptGetHashParam function retrieves data that governs the operations of a
hash object. The actual hash value can also be retrieved by using this function.
CryptHashData
The CryptHashData function adds data to a specified hash object. This function and
CryptHashSessionKey can be called multiple times to compute the hash on long
data streams or discontinuous data streams. Before calling this function, the
CryptCreateHash function must be called to create a handle of a hash object.
CryptHashSessionKey
The CryptHashSessionKey function computes the cryptographic hash of a key
object. This function can be called multiple times with the same hash handle to
compute the hash of multiple keys. Calls to CryptHashSessionKey can be
interspersed with calls to CryptHashData. Before calling this function, the
CryptCreateHash function must be called to create the handle of a hash object.
CryptSetHashParam
The CryptSetHashParam function customizes the operations of a hash object.
CryptSignHash
The CryptSignHash function signs data. Because all signature algorithms are
asymmetric and thus slow, the CryptoAPI does not allow data be signed directly.
Instead, data is first hashed and CryptSignHash is used to sign the hash. The
crypto module supports signing with DSS.
CryptVerifySignature
The CryptVerifySignature function verifies the signature of a hash object. Before
calling this function, the CryptCreateHash function must be called to create the
handle of a hash object. CryptHashData or CryptHashSessionKey is then used to
add data or session keys to the hash object. The crypto module supports verifying
DSS signatures.
After this function has been completed, only CryptDestroyHash can be called using
the hHash handle.
CryptDuplicateHash
The CryptDuplicateHash function is used to duplicate, make a copy of, the state of a
hash and returns a handle to this new hash. The CryptDestroyHash function must
be used on both the handle to the original hash and the newly duplicated hash.
10
The DSSENH cryptomodule manages keys in the following manner.
Key Material
DSSENH can create and use keys for the following algorithms: DSS, Diffie-Hellman,
RC2, RC4, DES, DES40, and 3DES.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Structures\Cryptography Structures for more
information about key formats and structures.
Key Generation
Random keys can be generated by calling the CryptGenKey() function. Keys can
also be derived from known values via the CryptDeriveKey() function. DSS keys are
generated and validated following the manner described in FIPS PUB 186-1. DES
key are generated and validated following the manner described in FIPS PUB 46-2
and FIPS PUB 81.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
Key Entry and Output
Keys can be both exported and imported out of and into DSSENH via
CryptExportKey() and CryptImportKey(). Exported private keys may be encrypted
with a symmetric key passed into the CryptExportKey function. Any of the
symmetric algorithms supported by the crypto module may be used to encrypt
private keys for export (DES, 3DES, DES40, RC4 or RC2). When private keys are
generated or imported from archival, they are covered with the Microsoft Windows
2000 Data Protection API (DPAPI) and then outputted to the file system in the
covered form.
Symmetric key entry and output is done by exchanging keys using the recipient’s
asymmetric public key. Symmetric key entry and output may also be done by
exporting a symmetric key wrapped with another symmetric key.
See MSDN Library\Platform SDK\Windows Base Services\Security\CryptoAPI
2.0\CryptoAPI Reference\CryptoAPI Functions\Base Cryptography Functions\Key
Generation and Exchange Functions for more information.
{ TC "CRYPTOGRAPHIC
KEY MANAGEMENT" \F
SP }CRYPTOGRAPHIC
KEY MANAGEMENT
11
Key Storage
DSSENH offloads the key storage operations to the Microsoft Windows 2000
operating system. Keys are not stored in the cryptographic module, private keys are
encrypted by the Microsoft Data Protection API (DPAPI) service, and then stored in
the Microsoft Windows 2000 file system. Keys are zeroized from memory after use.
Only the key used for power up self-testing is stored in the cryptographic module.
When an Authenticated User requests a keyed cryptographic operation from
DSSENH his/her keys are retrieved from the file system.
DPAPI uses a two-phase algorithm for shrouding the Secret Key (SK) used to
encrypt data. Phase 2 occurs by default only if there is a Domain Controller
associated with the user. Therefore in the local user case, the SK is protected by a
local LSA secret. SYSKEY should be enabled to prevent access to this key. Refer
to NT4/win2k documentation for info on SYSKEY.
Phase 1: Local Agent
In the first phase, the system shrouds the secret locally, relying on the service run
as Local System to protect secrets. This protection shrouds the data both as it
travels on the wire and also blinds the data from the DC. Thus, the shrouding
ensures that no remote user (even a “phase 2” remote recovery agent) can decrypt
the data independent from the local system.
Recovery setup
1. Agent has data D1 to shroud
2. Agent uses secret key SK encrypt D1
3. Agent stores SK in the user hive ACLed to local agent
4. Agent has shrouded E{D1}
Initiate recovery
1. Agent has E{D1} to unshroud
2. Agent retrieves secret key SK from user hive
3. Agent uses secret key SK to decrypt E{D1}
4. Agent has unshrouded D1
Phase 2: Remote Agent
In the second phase, if the machine is networked, the shrouded secret is sent to the
domain controller (DC) for an identification stamp and second shrouding. This
second shrouding will ensure that a roaming user profile is not self-contained, but
needs an interactive logon to successfully recover the master key.
12
Recovery setup
5. User sends data D2 to remote agent
6. Agent uses secret monster key K, random R2, HMACs to derive SymKeyM.
7. Use SymKeyM to MAC {userid, D2} -> m{userid, D2}
8. Agent uses secret monster key K, random R3, HMACs to derive SymKeyK.
9. Use SymKeyK to encrypt { m{userid, D2} , R2 }
10. Agent returns recovery field E{ m{userid, D2}, R2 }, R3 to User
11. User stores recovery field E{ m{userid, D2}, R2 }, R3
Initiate recovery
5. User sends recovery field E{ m{userid, D2}, R2 }, R3 to remote agent
6. Agent uses secret monster key K, HMACs with R3 to re-derive SymKeyK.
7. SymKeyK used to decrypt m{userid, D2}, R2
8. Agent uses secret monster key K, HMACs with R2 to re-derive SymKeyM.
9. SymKeyM used to check MAC on {userid, D2}.
10. Agent returns D2 if userid matches current recovery requestor.
These phases can be nested such that D2 = E{D1}, which allows neither of the
agents to recover the data barring collusion.
Key Archival
DSSENH does not directly archive cryptographic keys. The Authenticated User may
choose to export a cryptographic key labeled as exportable (cf. “Key Input and
Output” above), but management of the secure archival of that key is the
responsibility of the user.
Key Destruction
All keys are destroyed and their memory location zeroized when the Authenticated
User calls CryptDestroyKey on that key handle. Private keys (which are stored by
the operating system in covered format in the protected storage system portion of
the NT4.0 OS) are destroyed when the Authenticated User calls
CryptAcquireContext with the CRYPT_DELETE_KEYSET flag.
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Mandatory
Software tests via a DES MAC of library image
• RC4 encrypt/decrypt KAT
• RC2 ECB encrypt/decrypt KAT
• DES ECB encrypt/decrypt KAT
• DES40 ECB encrypt/decrypt KAT
• 3DES ECB encrypt/decrypt KAT
• 3DES 112 ECB encrypt/decrypt KAT
• RC2 CBC encrypt/decrypt KAT
• DES CBC encrypt/decrypt KAT
• DES40 CBC encrypt/decrypt KAT
• 3DES CBC encrypt/decrypt KAT
• 3DES 112 CBC encrypt/decrypt KAT
• MD5 hash KAT
• SHA-1 hash KAT
• DSS pairwise consistency test
• Diffie-Hellman pairwise consistency test
Conditional
The following are initiated at key generation:
• DSS pairwise consistency test
• Diffie-Hellman pairwise consistency test
{ TC "SELF-TESTS" \F SP
}SELF-TESTS
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The following items address requirements not addressed above.
Cryptographic Bypass
Cryptographic bypass is not support in DSSENH.
Operation Authentication
DSSENH inherits all authentication from the Microsoft Windows 2000 operating
system upon which it runs. Microsoft Windows 2000 requires authentication from a
trusted control base (TCB) before a user is able to access system services. Once a
user is authenticated from the TCB, a process is created bearing the Authenticated
User’s security token. All subsequent processes and threads created by that
Authenticated User are implicitly assigned the parent’s (thus the Authenticated
User’s) security token. Every user that has been authenticated by Microsoft
Windows 2000 is naturally assigned the Authenticated User role when he/she
accesses DSSENH.
Identity-based Authentication
While all Authenticated Users are assigned the same role and thus have access to
the same complete set of services, individual Authenticated Users may only access
key containers which they themselves have created. DSSENH assumes the
authentication of the user and enforces it by running in a thread with the
Authenticated User’s security token.
ModularExpOffload
The ModularExpOffload function offloads modular exponentiation from a CSP to a
hardware accelerator. The CSP will check in the registry for the value
HKLM\Software\Microsoft\Cryptography\ExpoOffload that can be the name of a
DLL. The CSP uses LoadLibrary to load that DLL and calls GetProcAddress to get
the OffloadModExpo entry point in the DLL specified in the registry. The CSP uses
the entry point to perform all modular exponentiations for both public and private
key operations. Two checks are made before a private key is offloaded.
Operating System Security
The DSSENH cryptomodule is intended to run on Windows 2000 in Single User
Mode.
{ TC "MISCELLANEOUS"
\F SP }MISCELLANEOUS
15
When an operating system process loads the cryptomodule into memory, the
cryptomodule runs a DES MAC on the cryptomodule’s disk image of DSSENH.DLL,
excluding the DES MAC, checksum, and export signature resources. This MAC is
compared to the value stored in the DES MAC resource. Initialization will only
succeed if the two values are equal.
Each operating system process creates a unique instance of the cryptomodule that
is wholly dedicated to that process. The cryptomodule is not shared between
processes.
16
For the latest information on Windows NT Server, check out our World Wide Web
site at http://www.microsoft.com/ntserver or the Windows NT Server Forum on the
MSN™ network of Internet services (GO WORD: MSNTS)
{ TC "FOR MORE
INFORMATION" \F SP
}FOR MORE
INFORMATION
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