Is a keyed-hash function that provides message authentication using the HMAC algorithm and the SHA-256 hash function, passing its arguments in hexadecimal format.
Public Declare Function SHA2_HmacHex Lib "diCryptoSys.dll"
(ByVal strDigest As String, ByVal strHexData As String,
ByVal strHexKey As String) As Long
nRet = SHA2_HmacHex(strDigest, strHexData, strHexKey)
String variable of sufficient length to
receive the message digest in hex format.String containing the text of the message in hexadecimal format.String containing the key in hexadecimal format.
long _stdcall SHA2_HmacHex(char *strDigest, const char *sHexText, const char *strHexKey);
Long: If successful, the return value is 0;
otherwise it returns a non-zero error code.
Sha256.Hmac Method (String, String)
sha256.HmacHex
Public Function HmacHex(ByVal strHexText As String, ByVal strHexKey As String) As String
See sha256.HmacHex.
strDigest must be at least 64 (API_MAX_SHA2_CHARS) characters long (65 in a C program). strData and strKey are expected to be an even number of characters long, i.e. representing complete byte values. Any trailing odd character will be ignored.
'Example from Wei Dai's Crypto++ test vectors 'fipstest.cpp - written and placed in the public domain by Wei Dai 'From http://trolocsis.com/crypto++/fipstest_8cpp-source.html 'MAC_KnownAnswerTest<HMAC<SHA256> >( '"303132333435363738393a3b3c3d3e3f40414243", '"abc", '"D28363F335B2DAE468793A38680DEA9F7FB8BE1DCEDA197CDB3B1CB59A9F6422"); Dim nRet As Long Dim strDigest As String * 64 Dim strMessage As String Dim sHexMsg As String Dim sCorrect As String sCorrect = "d28363f335b2dae468793a38680dea9f7fb8be1dceda197cdb3b1cb59a9f6422" ' Convert data to hex format sHexMsg = cnvHexStrFromString("abc") nRet = SHA2_HmacHex(strDigest, sHexMsg, "303132333435363738393a3b3c3d3e3f40414243") Debug.Print "Digest =" & strDigest Debug.Print "Correct=" & sCorrect Debug.Assert (strDigest = sCorrect)
This should result in output as follows:
Digest =d28363f335b2dae468793a38680dea9f7fb8be1dceda197cdb3b1cb59a9f6422 Correct=d28363f335b2dae468793a38680dea9f7fb8be1dceda197cdb3b1cb59a9f6422