CryptHashData (Compact 2013)

3/28/2014

This function adds data to a specified hash object. This function and the CryptHashSessionKey function can be called multiple times to compute the hash on long streams or on discontinuous streams.

Before calling this function, the CryptCreateHash function must be called to create a handle to a hash object.

Syntax

BOOL WINAPI CryptHashData( 
  HCRYPTHASH hHash, 
  BYTE* pbData,
  DWORD dwDataLen, 
  DWORD dwFlags
);

Parameters

• hHash
  [in] HCRYPTHASH handle to the hash object created by calling the CryptCreateHash function.

• pbData
  [in] Pointer to a buffer containing the data to be hashed.

• dwDataLen
  [in] Specifies the number of bytes of data to be hashed. This value must be zero if the CRYPT_USERDATA flag is set.

• dwFlags
  [in] Bitmask of flags. All Microsoft cryptographic service providers ignore this parameter. The CRYPT_USERDATA flag value is defined for other cryptographic service providers (CSPs).

  If the CRYPT_USERDATA flag is set, the CSP prompts the user to input data directly and adds the data to the hash. Access directly to the hash data is not allowed; instead, applications manipulate the hash values through the hash handle. This flag allows the users to enter a personal identification number (PIN) into the system.

Return Value

TRUE indicates success. FALSE indicates failure. To get extended error information, call the GetLastError function.

The following table shows the common values for the GetLastError function. The error values prefaced by NTE are generated by the particular CSP you are using.

Value	Description
ERROR_INVALID_HANDLE	One of the parameters specifies an invalid handle.
ERROR_INVALID_PARAMETER	One of the parameters contains an invalid value. This is most often an illegal pointer.
NTE_BAD_ALGID	The hHash handle specifies an algorithm that this CSP does not support.
NTE_BAD_FLAGS	The dwFlags parameter contains an invalid value.
NTE_BAD_HASH	The hash object specified by the hHash parameter is invalid.
NTE_BAD_HASH_STATE	An attempt was made to add data to a hash object that is already marked as finished.
NTE_BAD_KEY	A keyed hash algorithm is being used, but the session key is no longer valid. This error will be generated if the session key is destroyed before the hashing operation is complete.
NTE_BAD_LEN	The CRYPT_USERDATA flag is set and the dwDataLen parameter has a nonzero value.
NTE_BAD_UID	The CSP context that was specified when the hash object was created cannot be found.
NTE_FAIL	The function failed in some unexpected way.
NTE_NO_MEMORY	The CSP ran out of memory during the operation.

Example Code

See CryptGetHashParam.

Requirements

Header	wincrypt.h
Library	coredll.lib

See Also

Reference

Cryptography Functions
CryptCreateHash
CryptHashSessionKey
CryptSignHash