(C) AES-CMAC

Demonstrates using the AES-CMAC algorithm, which is a keyed hash function similar to HMAC and Poly1305.

Note: Chilkat added AES-CMAC in version 9.5.0.95.

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#include <C_CkCrypt2.h>
#include <C_CkBinData.h>

void ChilkatSample(void)
    {
    HCkCrypt2 crypt;
    const char *keyHex;
    BOOL success;
    const char *messageBytes;
    HCkBinData bd;
    const char *cmac;
    const char *plainText;
    const char *encTag;

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    crypt = CkCrypt2_Create();

    // Set the MAC algorithm to AES-CMAC
    CkCrypt2_putMacAlgorithm(crypt,"aes-cmac");

    // AES-CMAC always uses a 16-byte (128-bit) MAC key.
    keyHex = "2b7e151628aed2a6abf7158809cf4f3c";
    success = CkCrypt2_SetMacKeyEncoded(crypt,keyHex,"hex");

    // Let's compute the AES-CMAC for the test vector at https://www.rfc-editor.org/rfc/rfc4493#appendix-A
    // Here we have 64 bytes in hex representation.
    messageBytes = "6bc1bee22e409f96e93d7e117393172aae2d8a571e03ac9c9eb76fac45af8e5130c81c46a35ce411e5fbc1191a0a52eff69f2445df4f9b17ad2b417be66c3710";

    bd = CkBinData_Create();
    CkBinData_AppendEncoded(bd,messageBytes,"hex");

    // Compute the AES-CMAC for the bytes contained in bd and return the AES-CMAC in hex representation.
    CkCrypt2_putEncodingMode(crypt,"hex_lower");
    cmac = CkCrypt2_macBdENC(crypt,bd);
    printf("%s\n",cmac);
    // Output should be: 51f0bebf7e3b9d92fc49741779363cfe

    // Now do the same for a string:
    plainText = "'Twas brillig, and the slithy toves\nDid gyre and gimble in the wabe:\nAll mimsy were the borogoves,\nAnd the mome raths outgrabe.";
    encTag = CkCrypt2_macStringENC(crypt,plainText);
    printf("%s\n",encTag);

    // Output should be: 4fca1fcbd265048d247f99ab57fa3ceb


    CkCrypt2_Dispose(crypt);
    CkBinData_Dispose(bd);

    }