The CryptHashMessage function creates a hash of the message.
BOOL CryptHashMessage( PCRYPT_HASH_MESSAGE_PARA pHashPara, BOOL fDetachedHash, DWORD cToBeHashed, const BYTE *  rgpbToBeHashed, DWORD  rgcbToBeHashed, BYTE *pbHashedBlob, DWORD *pcbHashedBlob, BYTE *pbComputedHash, DWORD *pcbComputedHash );
A pointer to a CRYPT_HASH_MESSAGE_PARA structure that contains the hash parameters.
If this parameter is set to TRUE, only pbComputedHash is encoded in pbHashedBlob. Otherwise, both rgpbToBeHashed and pbComputedHash are encoded.
The number of array elements in rgpbToBeHashed and rgcbToBeHashed. This parameter can only be one unless fDetachedHash is set to TRUE.
An array of pointers to buffers that contain the contents to be hashed.
An array of sizes, in bytes, of the buffers pointed to by rgpbToBeHashed.
A pointer to a buffer to receive the hashed message encoded for transmission.
This parameter can be NULL if the hashed message is not needed for additional processing or to set the size of the hashed message for memory allocation purposes. A hashed message will not be returned if this parameter is NULL. For more information, see Retrieving Data of Unknown Length.
A pointer to a DWORD that specifies the size, in bytes, of the buffer pointed to by the pbHashedBlob parameter. When the function returns, this variable contains the size, in bytes, of the decrypted message copied to pbHashedBlob. This parameter must be the address of a DWORD and not NULL or the length of the buffer will not be returned.
A pointer to a buffer to receive the newly created hash value. This parameter can be NULL if the newly created hash is not needed for additional processing, or to set the size of the hash for memory allocation purposes. For more information, see Retrieving Data of Unknown Length.
A pointer to a DWORD that specifies the size, in bytes, of the buffer pointed to by the pbComputedHash parameter. When the function returns, this DWORD contains the size, in bytes, of the newly created hash that was copied to pbComputedHash.
If the function succeeds, the function returns nonzero (TRUE).
If the function fails, it returns zero (FALSE). For extended error information, call GetLastError.
||The message encoding type is not valid. Currently only PKCS_7_ASN_ENCODING is supported. The cbSize in *pHashPara is not valid.|
||If the buffer specified by the pbHashedBlob parameter is not large enough to hold the returned data, the function sets the ERROR_MORE_DATA code and stores the required buffer size, in bytes, into the variable pointed to by pbHashedBlob.|
|Minimum supported client||Windows XP [desktop apps only]|
|Minimum supported server||Windows Server 2003 [desktop apps only]|