CryptHashData info  Overview  Group

The CryptHashData function is used to compute the cryptographic hash on a stream of data. This function and CryptHashSessionKey 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 get a handle to a hash object.

BOOL CRYPTFUNC CryptHashData(

Parameters

hHash

[in] A handle to the hash object. An application obtains this handle using the CryptCreateHash function.

pbData

[in] The address of the data to be hashed.

dwDataLen

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

dwFlags

[in] The flag values. The following values are currently defined:

• CRYPT_USERDATA

  When this flag is set, the CSP will prompt the user to input some data directly. This is then added to the hash. The application is not allowed access to the data. For example, this flag can be used to allow the user to enter a PIN into the system.

The Microsoft RSA Base Provider ignores this parameter.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To retrieve extended error information, use the GetLastError function.

The following table lists the error codes most commonly returned by the GetLastError function. The error codes prefaced by “NTE” are generated by the particular CSP you are using.

Example

See the “Example” section in the CryptSignHash function.

See Also

CryptCreateHash, CryptHashSessionKey, CryptSignHash 

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