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CryptVerifyMessageHash function (wincrypt.h)

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The CryptVerifyMessageHash function verifies the hash of specified content.

Syntax

BOOL CryptVerifyMessageHash(
  [in]                PCRYPT_HASH_MESSAGE_PARA pHashPara,
  [in]                BYTE                     *pbHashedBlob,
  [in]                DWORD                    cbHashedBlob,
  [out]               BYTE                     *pbToBeHashed,
  [in, out]           DWORD                    *pcbToBeHashed,
  [out, optional]     BYTE                     *pbComputedHash,
  [in, out, optional] DWORD                    *pcbComputedHash
);

Parameters

[in] pHashPara

A pointer to a CRYPT_HASH_MESSAGE_PARA structure containing hash parameters.

[in] pbHashedBlob

A pointer to a buffer containing original content and its hash.

[in] cbHashedBlob

The size, in bytes, of the original hash buffer.

[out] pbToBeHashed

A pointer to a buffer to receive the original content that was hashed.

This parameter can be NULL if the original content is not needed for additional processing, or to set the size of the original content for memory allocation purposes. For more information, see Retrieving Data of Unknown Length.

[in, out] pcbToBeHashed

A pointer to a DWORD specifying the size, in bytes, of the pbToBeHashed buffer. When the function returns, this variable contains the size, in bytes, of the original content copied to pbToBeHashed. The original content will not be returned if this parameter is NULL.

Note  When processing the data returned, applications must use the actual size of the data returned. The actual size can be slightly smaller than the size of the buffer specified on input. (On input, buffer sizes are usually specified large enough to ensure that the largest possible output data will fit in the buffer.) On output, the variable pointed to by this parameter is updated to reflect the actual size of the data copied to the buffer.
 

[out, optional] pbComputedHash

A pointer to a buffer to receive the computed hash. This parameter can be NULL if the created hash is not needed for additional processing, or to set the size of the original content for memory allocation purposes. For more information, see Retrieving Data of Unknown Length.

[in, out, optional] pcbComputedHash

A pointer to a DWORD specifying the size, in bytes, of the pbComputedHash buffer. When the function returns, this variable contains the size, in bytes, of the created hash. The hash is not returned if this parameter is NULL.

Note  When processing the data returned, applications must use the actual size of the data returned. The actual size can be slightly smaller than the size of the buffer specified on input. (On input, buffer sizes are usually specified large enough to ensure that the largest possible output data will fit in the buffer.) On output, the variable pointed to by this parameter is updated to reflect the actual size of the data copied to the buffer.
 

Return value

If the function succeeds, the return value is nonzero (TRUE).

If the function fails, the return value is zero (FALSE).

For extended error information, call GetLastError.

The following lists the error codes most commonly returned by the GetLastError function.

Return code Description
CRYPT_E_UNEXPECTED_MSG_TYPE
 Not a hashed cryptographic message.
E_INVALIDARG
 The message encoding type is not valid. Currently only PKCS_7_ASN_ENCODING is supported. The cbSize in *pHashPara is not valid.
ERROR_MORE_DATA
 If the buffer specified by the pbToBeHashed 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 pcbToBeHashed.
 
Note  Errors from the called functions CryptCreateHash, CryptHashData, and CryptGetHashParam might be propagated to this function.

If the function fails, GetLastError may return an Abstract Syntax Notation One (ASN.1) encoding/decoding error. For information about these errors, see ASN.1 Encoding/Decoding Return Values.

 

Requirements

Requirement Value
Minimum supported client Windows XP [desktop apps only]
Minimum supported server Windows Server 2003 [desktop apps only]
Target Platform Windows
Header wincrypt.h
Library Crypt32.lib
DLL Crypt32.dll

See also

CryptVerifyDetachedMessageHash

Simplified Message Functions