Message authentication code (MAC)

HMAC

MAC examples

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <qcrypto/qcrypto.h>
#include <qcrypto/qcrypto_error.h>
#include <qcrypto/qcrypto_keys.h>

int main(void)
{
    int ret;
    int result;
    qcrypto_ctx_t *qctx = NULL;
    qcrypto_key_t *qkey = NULL;
    qcrypto_ctx_t *qkeyctx = NULL;

    const uint8_t inputbuf[] = {
        0x53, 0x61, 0x6d, 0x70, 0x6c, 0x65, 0x20, 0x6d, 0x65, 0x73, 0x73, 0x61,
        0x67, 0x65, 0x20, 0x66, 0x6f, 0x72, 0x20, 0x6b, 0x65, 0x79, 0x6c, 0x65,
        0x6e, 0x3c, 0x62, 0x6c, 0x6f, 0x63, 0x6b, 0x6c, 0x65, 0x6e
    };
    const size_t inputsize = sizeof(inputbuf);
    const uint8_t *input_bin = inputbuf;

    const uint8_t keybuf[] = {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
        0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
        0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f
    };
    const size_t keysize = sizeof(keybuf);
    const uint8_t *key_bin = keybuf;

    const uint8_t mac_buf[] = {
        0xa2, 0x8c, 0xf4, 0x31, 0x30, 0xee, 0x69, 0x6a, 0x98, 0xf1, 0x4a, 0x37,
        0x67, 0x8b, 0x56, 0xbc, 0xfc, 0xbd, 0xd9, 0xe5, 0xcf, 0x69, 0x71, 0x7f,
        0xec, 0xf5, 0x48, 0x0f, 0x0e, 0xbd, 0xf7, 0x90
    };
    const size_t macsize = sizeof(mac_buf);

    uint8_t mac_cmpbuf[512];
    uint8_t *mac_cmp = mac_cmpbuf;
    size_t mac_cmp_size = macsize;

    /* Initialize the Qcrypto Library */
    ret = qcrypto_init(QCRYPTO_INIT_LAZY, NULL);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcryto_init() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

     /* Request symmetric keygen */
    ret = qcrypto_keygen_request("symmetric", NULL, 0, &qkeyctx);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_keygen_request() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Request hmac-sha256 */
    ret = qcrypto_mac_request("hmac-sha256", NULL, 0, &qctx);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_mac_request() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Load key */
    ret = qcrypto_key_from_mem(qkeyctx, &qkey, key_bin, keysize);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_key_from_mem() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Initialize MAC */
    ret = qcrypto_mac_init(qctx, qkey);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_mac_init() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Update MAC */
    ret = qcrypto_mac_update(qctx, input_bin, inputsize);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_mac_update() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Finalize MAC */
    ret = qcrypto_mac_final(qctx, mac_cmp, &mac_cmp_size);
    if (ret != QCRYPTO_R_EOK) {
        fprintf(stderr, "qcrypto_mac_final() failed (%d:%s)\n", ret, qcrypto_strerror(ret));
        goto done;
    }

    /* Compare the results */
    result = memcmp(mac_cmp, mac_buf, mac_cmp_size);
    if(result == 0) {
         printf("Computed mac matches with expected mac\n");
    } else {
         fprintf(stderr, "Computed mac failed to match with expected mac\n");
    }
    goto done;

done:
    /* Release all context handles */
    qcrypto_release_ctx(qctx);
    qcrypto_release_ctx(qkeyctx);

    /* Release the key handle */
    qcrypto_release_key(qkey);

    /* Uninitialize the Qcrypto Library */
    qcrypto_uninit();

    return ret;
}