



#include <string.h>
#include <stdio.h>
#include <openssl/crypto.h>
#include <openssl/core_names.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/cmac.h>
#include <openssl/params.h>


static unsigned char key[] = {
    0x6c, 0xde, 0x14, 0xf5, 0xd5, 0x2a, 0x4a, 0xdf,
    0x12, 0x39, 0x1e, 0xbf, 0x36, 0xf9, 0x6a, 0x46,
    0x48, 0xd0, 0xb6, 0x51, 0x89, 0xfc, 0x24, 0x85,
    0xa8, 0x8d, 0xdf, 0x7e, 0x80, 0x14, 0xc8, 0xce,
};

static const unsigned char data[] =
    "To be, or not to be, that is the question,\n"
    "Whether tis nobler in the minde to suffer\n"
    "The ſlings and arrowes of outragious fortune,\n"
    "Or to take Armes again in a sea of troubles,\n"
    "And by opposing, end them, to die to sleep;\n"
    "No more, and by a sleep, to say we end\n"
    "The heart-ache, and the thousand natural shocks\n"
    "That flesh is heir to? tis a consumation\n"
    "Devoutly to be wished. To die to sleep,\n"
    "To sleepe, perchance to dreame, Aye, there's the rub,\n"
    "For in that sleep of death what dreams may come\n"
    "When we haue shuffled off this mortal coil\n"
    "Must give us pause. There's the respect\n"
    "That makes calamity of so long life:\n"
    "For who would bear the Ships and Scorns of time,\n"
    "The oppressor's wrong, the proud man's Contumely,\n"
    "The pangs of dispised love, the Law's delay,\n"
;


static const unsigned char expected_output[] = {
    0x67, 0x92, 0x32, 0x23, 0x50, 0x3d, 0xc5, 0xba,
    0x78, 0xd4, 0x6d, 0x63, 0xf2, 0x2b, 0xe9, 0x56,
};


static const char *propq = NULL;

int main(void)
{
    int ret = EXIT_FAILURE;
    OSSL_LIB_CTX *library_context = NULL;
    EVP_MAC *mac = NULL;
    EVP_MAC_CTX *mctx = NULL;
    unsigned char *out = NULL;
    size_t out_len = 0;
    OSSL_PARAM params[4], *p = params;
    char cipher_name[] = "AES-256-CBC";

    library_context = OSSL_LIB_CTX_new();
    if (library_context == NULL) {
        fprintf(stderr, "OSSL_LIB_CTX_new() returned NULL\n");
        goto end;
    }

    
    mac = EVP_MAC_fetch(library_context, "CMAC", propq);
    if (mac == NULL) {
        fprintf(stderr, "EVP_MAC_fetch() returned NULL\n");
        goto end;
    }

    
    mctx = EVP_MAC_CTX_new(mac);
    if (mctx == NULL) {
        fprintf(stderr, "EVP_MAC_CTX_new() returned NULL\n");
        goto end;
    }

    
    *p++ = OSSL_PARAM_construct_utf8_string(OSSL_MAC_PARAM_CIPHER, cipher_name,
                                            sizeof(cipher_name));
    *p = OSSL_PARAM_construct_end();

    
    if (!EVP_MAC_init(mctx, key, sizeof(key), params)) {
        fprintf(stderr, "EVP_MAC_init() failed\n");
        goto end;
    }

    
    if (!EVP_MAC_update(mctx, data, sizeof(data))) {
        fprintf(stderr, "EVP_MAC_update() failed\n");
        goto end;
    }

    
    if (!EVP_MAC_final(mctx, NULL, &out_len, 0)) {
        fprintf(stderr, "EVP_MAC_final() failed\n");
        goto end;
    }
    out = OPENSSL_malloc(out_len);
    if (out == NULL) {
        fprintf(stderr, "malloc failed\n");
        goto end;
    }
    
    if (!EVP_MAC_final(mctx, out, &out_len, out_len)) {
        fprintf(stderr, "EVP_MAC_final() failed\n");
        goto end;
    }

    printf("Generated MAC:\n");
    BIO_dump_indent_fp(stdout, out, out_len, 2);
    putchar('\n');

    if (out_len != sizeof(expected_output)) {
        fprintf(stderr, "Generated MAC has an unexpected length\n");
        goto end;
    }

    if (CRYPTO_memcmp(expected_output, out, sizeof(expected_output)) != 0) {
        fprintf(stderr, "Generated MAC does not match expected value\n");
        goto end;
    }

    ret = EXIT_SUCCESS;
end:
    if (ret != EXIT_SUCCESS)
        ERR_print_errors_fp(stderr);
    
    OPENSSL_free(out);
    EVP_MAC_CTX_free(mctx);
    EVP_MAC_free(mac);
    OSSL_LIB_CTX_free(library_context);
    return ret;
}
