(MFC) HMAC Hex String

Demonstrates how to compute an HMAC using a hexidecimal key and data.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkCrypt2.h>
#include <CkBinData.h>

void ChilkatSample(void)
    {
    CkString strOut;

    CkCrypt2 crypt;

    bool success = crypt.UnlockComponent("Anything for 30-day trial");
    if (success != true) {
        strOut.append(crypt.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    //  Set the MAC algorithm to HMAC
    crypt.put_MacAlgorithm("hmac");

    //  Our HMAC key will be the bytes represented in the following hex string.
    //  In other words, the HMAC key is composed of the bytes 0x41, 0xC2, 0x1C, ...
    //  (It is not composed of the us-ascii string '4', '1', 'C', ...)
    const char *keyHex = "41C21CB9D7A02FC5D4FADB9E4755B9DE";
    success = crypt.SetMacKeyEncoded(keyHex,"hex");

    //  Our desire is to HMAC the bytes represented in the following string:
    const char *dataHex = "C22078065B01460001000000010062043BF5B18228C8E02D17BCFE4E00561FA6DEC216EA97195CEB579942E275C21932258E3CD391E507FF4E7FD4C787A8447DA111C54A9C1795E7FF4C0BAA2EDA";

    //  We'll need to decode the hex to binary:
    CkBinData bd;
    bd.AppendEncoded(dataHex,"hex");

    //  Do the HMAC-SHA256 hash and return as a hex string:
    crypt.put_EncodingMode("hex");
    crypt.put_HashAlgorithm("sha-256");
    const char *macHex = crypt.macBdENC(bd);
    strOut.append(macHex);
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }