C++ HMAC_CTX_init函数代码示例

int main() {
    // The secret key for hashing
    const char key[] = "012345678";

    // The data that we're going to hash
    char data[] = "hello world";

    // Be careful of the length of string with the choosen hash engine. SHA1 needed 20 characters.
    // Change the length accordingly with your choosen hash engine.
    unsigned char* result;
    unsigned int len = 20;

    result = (unsigned char*)malloc(sizeof(char) * len);

    HMAC_CTX ctx;
    HMAC_CTX_init(&ctx);

    // Using sha1 hash engine here.
    // You may use other hash engines. e.g EVP_md5(), EVP_sha224, EVP_sha512, etc
    HMAC_Init_ex(&ctx, key, strlen(key), EVP_sha1(), NULL);
    HMAC_Update(&ctx, (unsigned char*)&data, strlen(data));
    HMAC_Final(&ctx, result, &len);
    HMAC_CTX_cleanup(&ctx);

    printf("HMAC digest: ");

    for (int i = 0; i != len; i++)
        printf("%02x", (unsigned int)result[i]);

    printf("\n");

    free(result);

    return 0;
}

//These functions should be replaced with VHMS API calls
int te_digest_init(EVP_MD_CTX *ctx) {
    struct te_hmac_sha1_digest_ctx *c = ctx->md_data;
    printf("Digest init. Current key: %s\n", c->key);
    HMAC_CTX_init(&c->hctx);
    HMAC_Init_ex(&c->hctx, c->key, c->key_ln, EVP_sha1(), 0);
    return 1;
}

HMACCTX hmac_init(const void *key, int len, enum ssh_hmac_e type) {
  HMACCTX ctx = NULL;

  ctx = malloc(sizeof(*ctx));
  if (ctx == NULL) {
    return NULL;
  }

#ifndef OLD_CRYPTO
  HMAC_CTX_init(ctx); // openssl 0.9.7 requires it.
#endif

  switch(type) {
    case SSH_HMAC_SHA1:
      HMAC_Init(ctx, key, len, EVP_sha1());
      break;
    case SSH_HMAC_MD5:
      HMAC_Init(ctx, key, len, EVP_md5());
      break;
    default:
      SAFE_FREE(ctx);
      ctx = NULL;
  }

  return ctx;
}

extern "C" HMAC_CTX* CryptoNative_HmacCreate(const uint8_t* key, int32_t keyLen, const EVP_MD* md)
{
    assert(key != nullptr || keyLen == 0);
    assert(keyLen >= 0);
    assert(md != nullptr);

    std::unique_ptr<HMAC_CTX> ctx(new (std::nothrow) HMAC_CTX);
    if (ctx == nullptr)
    {
        // Allocation failed
        return nullptr;
    }

    // NOTE: We can't pass nullptr as empty key since HMAC_Init_ex will interpret
    // that as request to reuse the "existing" key.
    uint8_t _;
    if (keyLen == 0)
        key = &_;

    HMAC_CTX_init(ctx.get());
    int ret = HMAC_Init_ex(ctx.get(), key, keyLen, md, nullptr);

    if (!ret)
    {
        return nullptr;
    }

    return ctx.release();
}

int winpr_HMAC_Init(WINPR_HMAC_CTX* ctx, int md, const BYTE* key, size_t keylen)
{
#if defined(WITH_OPENSSL)
	const EVP_MD* evp = winpr_openssl_get_evp_md(md);

	if (!evp)
		return -1;

	HMAC_CTX_init((HMAC_CTX*) ctx);

#if (OPENSSL_VERSION_NUMBER < 0x10000000L)
	HMAC_Init_ex((HMAC_CTX*) ctx, key, keylen, evp, NULL);
#else
	if (HMAC_Init_ex((HMAC_CTX*) ctx, key, keylen, evp, NULL) != 1)
		return -1;
#endif

#elif defined(WITH_MBEDTLS)
	const mbedtls_md_info_t* md_info;
	mbedtls_md_type_t md_type = winpr_mbedtls_get_md_type(md);
	md_info = mbedtls_md_info_from_type(md_type);

	if (!md_info)
		return -1;

	mbedtls_md_init((mbedtls_md_context_t*) ctx);

	if (mbedtls_md_setup((mbedtls_md_context_t*) ctx, md_info, 1) != 0)
		return -1;

	if (mbedtls_md_hmac_starts((mbedtls_md_context_t*) ctx, key, keylen) != 0)
		return -1;
#endif
	return 0;
}

// Signing functions
bool OSSLEVPMacAlgorithm::signInit(const SymmetricKey* key)
{
	// Call the superclass initialiser
	if (!MacAlgorithm::signInit(key))
	{
		return false;
	}

	// Initialize the context
	HMAC_CTX_init(&curCTX);

	// Initialize EVP signing
	if (!HMAC_Init(&curCTX, key->getKeyBits().const_byte_str(), key->getKeyBits().size(), getEVPHash()))
	{
		ERROR_MSG("HMAC_Init failed");

		HMAC_CTX_cleanup(&curCTX);

		ByteString dummy;
		MacAlgorithm::signFinal(dummy);

		return false;
	}

	return true;
}

static int hmac_fdigest(lua_State *L)
{
  HMAC_CTX c;
  unsigned char digest[EVP_MAX_MD_SIZE];
  size_t written = 0;
  unsigned int i;
  char *hex;
  const char *t = luaL_checkstring(L, 1);
  const char *s = luaL_checkstring(L, 2);
  const char *k = luaL_checkstring(L, 3);
  const EVP_MD *type = EVP_get_digestbyname(t);

  if (type == NULL) {
    luaL_argerror(L, 1, "invalid digest type");
    return 0;
  }

  HMAC_CTX_init(&c);
  HMAC_Init_ex(&c, k, lua_strlen(L, 3), type, NULL);
  HMAC_Update(&c, (unsigned char *)s, lua_strlen(L, 2));
  HMAC_Final(&c, digest, &written);

  if (lua_toboolean(L, 4))
    lua_pushlstring(L, (char *)digest, written);
  else
  {
    hex = calloc(sizeof(char), written*2 + 1);
    for (i = 0; i < written; i++)
      sprintf(hex + 2*i, "%02x", digest[i]);
    lua_pushlstring(L, hex, written*2);
    free(hex);
  }

  return 1;
}

static krb5_error_code
calculate_reply_hash(krb5_context context,
		     krb5_keyblock *key,
		     Kx509Response *rep)
{
    krb5_error_code ret;
    HMAC_CTX ctx;

    HMAC_CTX_init(&ctx);

    HMAC_Init_ex(&ctx, key->keyvalue.data, key->keyvalue.length,
		 EVP_sha1(), NULL);
    ret = krb5_data_alloc(rep->hash, HMAC_size(&ctx));
    if (ret) {
	HMAC_CTX_cleanup(&ctx);
	krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
	return ENOMEM;
    }

    HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
    if (rep->error_code) {
	int32_t t = *rep->error_code;
	do {
	    unsigned char p = (t & 0xff);
	    HMAC_Update(&ctx, &p, 1);
	    t >>= 8;
	} while (t);
    }

WINPR_HMAC_CTX* winpr_HMAC_New(void)
{
	WINPR_HMAC_CTX* ctx = NULL;

#if defined(WITH_OPENSSL)
	HMAC_CTX* hmac = NULL;
#if (OPENSSL_VERSION_NUMBER < 0x10100000L)
	if (!(hmac = (HMAC_CTX*) calloc(1, sizeof(HMAC_CTX))))
		return NULL;
	HMAC_CTX_init(hmac);
#else
	if (!(hmac = HMAC_CTX_new()))
		return NULL;
#endif
	ctx = (WINPR_HMAC_CTX*) hmac;

#elif defined(WITH_MBEDTLS)
	mbedtls_md_context_t* hmac;
	if (!(hmac = (mbedtls_md_context_t*) calloc(1, sizeof(mbedtls_md_context_t))))
		return NULL;

	mbedtls_md_init(hmac);

	ctx = (WINPR_HMAC_CTX*) hmac;
#endif

	return ctx;
}

static void doFile(FILE *fp)
{
  HMAC_CTX ctx;
  unsigned char digest[EVP_MAX_MD_SIZE];
  unsigned int i = 0, dlen = (unsigned int)sizeof(digest);
  size_t rd = 0;
  const char key[] = "etaonrishdlcupfm";
  unsigned char buf[4096];

  /* Initialise context */
  HMAC_CTX_init(&ctx);
  /* Set digest type and key in context */
  HMAC_Init_ex(&ctx, key, strlen(key), EVP_sha1(), NULL);
  /* Process input stream */
  do {
    rd = fread(buf,sizeof(char),sizeof(buf),fp);
    if(ferror(fp) || ((rd < sizeof(buf)) && !feof(fp))) exit(3);
    if(!HMAC_Update(&ctx, buf, (unsigned int)rd)) exit(4);
  } while(!feof(fp));

  /* Generate digest */
  if(!HMAC_Final(&ctx, digest, &dlen)) exit(5);
  HMAC_CTX_cleanup(&ctx);

  /* Display digest in hex */
  for(i = 0; i < dlen; i++) printf("%02x", digest[i]);
  printf("\n");
  return;
}

HmacHash::HmacHash()
{
    uint8 temp[SEED_KEY_SIZE] = { 0x38, 0xA7, 0x83, 0x15, 0xF8, 0x92, 0x25, 0x30, 0x71, 0x98, 0x67, 0xB1, 0x8C, 0x4, 0xE2, 0xAA };
    memcpy(&m_key, &temp, SEED_KEY_SIZE);
    HMAC_CTX_init(&m_ctx);
    HMAC_Init_ex(&m_ctx, &m_key, SEED_KEY_SIZE, EVP_sha1(), NULL);
}

static krb5_error_code
verify_req_hash(krb5_context context,
		const Kx509Request *req,
		krb5_keyblock *key)
{
    unsigned char digest[SHA_DIGEST_LENGTH];
    HMAC_CTX ctx;

    if (req->pk_hash.length != sizeof(digest)) {
	krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
			       "pk-hash have wrong length: %lu",
			       (unsigned long)req->pk_hash.length);
	return KRB5KDC_ERR_PREAUTH_FAILED;
    }

    HMAC_CTX_init(&ctx);
    HMAC_Init_ex(&ctx,
		 key->keyvalue.data, key->keyvalue.length,
		 EVP_sha1(), NULL);
    if (sizeof(digest) != HMAC_size(&ctx))
	krb5_abortx(context, "runtime error, hmac buffer wrong size in kx509");
    HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
    HMAC_Update(&ctx, req->pk_key.data, req->pk_key.length);
    HMAC_Final(&ctx, digest, 0);
    HMAC_CTX_cleanup(&ctx);

    if (memcmp(req->pk_hash.data, digest, sizeof(digest)) != 0) {
	krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
			       "pk-hash is not correct");
	return KRB5KDC_ERR_PREAUTH_FAILED;
    }
    return 0;
}

static int rtmp_handshake_make_digest(const uint8_t* key, size_t len, const uint8_t* ptr, size_t ptrlen, const uint8_t* digest, uint8_t* dst)
{
	static HMAC_CTX        *hmac;
	unsigned int            digestlen;

	if (hmac == NULL) {
#if OPENSSL_VERSION_NUMBER < 0x10100000L
		static HMAC_CTX  shmac;
		hmac = &shmac;
		HMAC_CTX_init(hmac);
#else
		hmac = HMAC_CTX_new();
#endif
	}

	HMAC_Init_ex(hmac, key, len, EVP_sha256(), NULL);
	if (digest)
	{
		assert(digest + SHA256_DIGEST_LENGTH <= ptr + ptrlen);
		HMAC_Update(hmac, ptr, digest - ptr);
		if (digest + SHA256_DIGEST_LENGTH < ptr + ptrlen)
			HMAC_Update(hmac, digest + SHA256_DIGEST_LENGTH, ptrlen - (digest - ptr) - SHA256_DIGEST_LENGTH);
	}
	else
	{
		HMAC_Update(hmac, ptr, ptrlen);
	}
	HMAC_Final(hmac, dst, &digestlen);
	assert(digestlen == SHA256_DIGEST_LENGTH);
	return 0;
}

static void
check_hmac(void)
{
    unsigned char buf[4] = { 0, 0, 0, 0 };
    char hmackey[] = "hello-world";
    size_t hmackey_size = sizeof(hmackey);
    unsigned int hmaclen;
    unsigned char hmac[EVP_MAX_MD_SIZE];
    HMAC_CTX c;

    char answer[20] = "\x2c\xfa\x32\xb7\x2b\x8a\xf6\xdf\xcf\xda"
	              "\x6f\xd1\x52\x4d\x54\x58\x73\x0f\xf3\x24";

    HMAC_CTX_init(&c);
    HMAC_Init_ex(&c, hmackey, hmackey_size, EVP_sha1(), NULL);
    HMAC_Update(&c, buf, sizeof(buf));
    HMAC_Final(&c, hmac, &hmaclen);
    HMAC_CTX_cleanup(&c);

    if (hmaclen != 20)
	errx(1, "hmaclen = %d\n", (int)hmaclen);

    if (ct_memcmp(hmac, answer, hmaclen) != 0)
	errx(1, "wrong answer\n");
}

static HMAC_CTX *HMAC_CTX_new(void)
{
    HMAC_CTX *ctx = OPENSSL_malloc(sizeof(HMAC_CTX));
    if (ctx != NULL)
        HMAC_CTX_init(ctx);
    return ctx;
}