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CPHashData function

The CPHashData function feeds data into a specified hash object.

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BOOL CPHashData(
  __in  HCRYPTPROV hProv,
  __in  HCRYPTHASH hHash,
  __in  const BYTE *pbData,
  __in  DWORD dwDataLen,
  __in  DWORD dwFlags
);

hProv [in]

A handle to a particular key container within the cryptographic service provider (CSP). This handle is obtained by a call to CPAcquireContext.

hHash [in]

A handle to a hash object. An application obtains this handle by using the CryptCreateHash function.

pbData [in]

Address of a buffer that contains the data to be hashed.

dwDataLen [in]

Number of bytes of data to be hashed. If dwFlags is set to CRYPT_USERDATA, this must be zero.

dwFlags [in]

The following value is currently defined.

Value	Meaning
CRYPT_USERDATA	The CSP must prompt the user to enter directly the data to be added to the hash. Any data entered is used and destroyed within this function, and the application has no access to it. This flag can be used to allow the user to enter a PIN, a password, or other unique identification into the system. Support for this flag is optional.

If the function succeeds, the function returns TRUE.

If the function fails, it returns FALSE, and the appropriate error code from the following table must be set using SetLastError.

Return code	Description
NTE_BAD_ALGID	The hHash handle specifies an algorithm that this CSP does not support.
NTE_BAD_FLAGS	The dwFlags parameter contains a value that is not valid.
NTE_BAD_HASH	The hash object specified by the hHash parameter is not valid.
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NTE_BAD_KEY	A keyed hash algorithm is being used, but the session key is no longer valid.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 operating 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 now be found.
NTE_FAIL	The function failed in some unexpected way.
NTE_NO_MEMORY	The CSP ran out of memory during the operation.