C++ DH_size函数代码示例

x4s_buf x4_dh_shared(const uint8 * g, size_t glen,
                     const uint8 * p, size_t plen,
                     const uint8 * x, size_t xlen,
                     const uint8 * gx, size_t gxlen,
                     const uint8 * gy, size_t gylen)
{
  DH     * dh;
  BIGNUM * bn;
  x4s_buf gxy = { 0 };

  /*  */
  x4_assert(gx && gxlen && gy && gylen);

  /*  */
  dh = _dh_init(g,glen, p,plen, x,xlen);
  x4_assert(dh);

  dh->pub_key = BN_bin2bn(gx, gxlen, 0);
  x4_assert(dh->pub_key);

  bn = BN_bin2bn(gy, gylen, 0);
  x4_assert(bn);

  x4_buf_resize(&gxy, DH_size(dh));
  DH_compute_key(gxy.data, bn, dh);

  DH_free(dh);
  return gxy;
}

bool
tr_dh_make_key (tr_dh_ctx_t   raw_handle,
                size_t        private_key_length,
                uint8_t     * public_key,
                size_t      * public_key_length)
{
  DH * handle = raw_handle;
  int dh_size, my_public_key_length;
  const BIGNUM * hand_pub_key;

  assert (handle != NULL);
  assert (public_key != NULL);


  DH_set_length(handle, private_key_length * 8);

  if (!check_result (DH_generate_key (handle)))
    return false;

  DH_get0_key (handle, &hand_pub_key, NULL);

  my_public_key_length = BN_bn2bin (hand_pub_key, public_key);
  dh_size = DH_size (handle);

  tr_dh_align_key (public_key, my_public_key_length, dh_size);

  if (public_key_length != NULL)
    *public_key_length = dh_size;

  return true;
}

void
tls_ctx_load_dh_params (struct tls_root_ctx *ctx, const char *dh_file,
    const char *dh_file_inline
    )
{
  DH *dh;
  BIO *bio;

  ASSERT(NULL != ctx);

  if (!strcmp (dh_file, INLINE_FILE_TAG) && dh_file_inline)
    {
      if (!(bio = BIO_new_mem_buf ((char *)dh_file_inline, -1)))
	msg (M_SSLDHERR, "Cannot open memory BIO for inline DH parameters");
    }
  else
    {
      /* Get Diffie Hellman Parameters */
      if (!(bio = BIO_new_file (dh_file, "r")))
	msg (M_SSLDHERR, "Cannot open %s for DH parameters", dh_file);
    }

  dh = PEM_read_bio_DHparams (bio, NULL, NULL, NULL);
  BIO_free (bio);

  if (!dh)
    msg (M_SSLDHERR, "Cannot load DH parameters from %s", dh_file);
  if (!SSL_CTX_set_tmp_dh (ctx->ctx, dh))
    msg (M_SSLDHERR, "SSL_CTX_set_tmp_dh");

  msg (D_TLS_DEBUG_LOW, "Diffie-Hellman initialized with %d bit key",
       8 * DH_size (dh));

  DH_free (dh);
}

static isc_result_t
openssldh_computesecret(const dst_key_t *pub, const dst_key_t *priv,
                        isc_buffer_t *secret)
{
    DH *dhpub, *dhpriv;
    int ret;
    isc_region_t r;
    unsigned int len;

    REQUIRE(pub->keydata.dh != NULL);
    REQUIRE(priv->keydata.dh != NULL);

    dhpub = pub->keydata.dh;
    dhpriv = priv->keydata.dh;

    len = DH_size(dhpriv);
    isc_buffer_availableregion(secret, &r);
    if (r.length < len)
        return (ISC_R_NOSPACE);
    ret = DH_compute_key(r.base, dhpub->pub_key, dhpriv);
    if (ret == 0)
        return (dst__openssl_toresult2("DH_compute_key",
                                       DST_R_COMPUTESECRETFAILURE));
    isc_buffer_add(secret, len);
    return (ISC_R_SUCCESS);
}

static int init_dh(SSL_CTX *ctx, const char *cert) {
    DH *dh;
    BIO *bio;

    assert(cert);

    bio = BIO_new_file(cert, "r");
    if (!bio) {
      ERR_print_errors_fp(stderr);
      return -1;
    }

    dh = PEM_read_bio_DHparams(bio, NULL, NULL, NULL);
    BIO_free(bio);
    if (!dh) {
        ERR("{core} Note: no DH parameters found in %s\n", cert);
        return -1;
    }

    LOG("{core} Using DH parameters from %s\n", cert);
    SSL_CTX_set_tmp_dh(ctx, dh);
    LOG("{core} DH initialized with %d bit key\n", 8*DH_size(dh));
    DH_free(dh);

    return 0;
}

ERL_NIF_TERM dh_compute_key_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
{/* (OthersPublicKey, MyPrivateKey, DHParams=[P,G]) */
    BIGNUM *other_pub_key = NULL,
        *dh_p = NULL,
        *dh_g = NULL;
    DH *dh_priv = DH_new();

    /* Check the arguments and get
          my private key (dh_priv),
          the peer's public key (other_pub_key),
          the parameters p & q
    */

    {
        BIGNUM *dummy_pub_key = NULL,
               *priv_key = NULL;
        ERL_NIF_TERM head, tail;

        if (!get_bn_from_bin(env, argv[0], &other_pub_key)
            || !get_bn_from_bin(env, argv[1], &priv_key)
            || !enif_get_list_cell(env, argv[2], &head, &tail)
            || !get_bn_from_bin(env, head, &dh_p)
            || !enif_get_list_cell(env, tail, &head, &tail)
            || !get_bn_from_bin(env, head, &dh_g)
            || !enif_is_empty_list(env, tail)

            /* Note: DH_set0_key() does not allow setting only the
             * private key, although DH_compute_key() does not use the
             * public key. Work around this limitation by setting
             * the public key to a copy of the private key.
             */
            || !(dummy_pub_key = BN_dup(priv_key))
            || !DH_set0_key(dh_priv, dummy_pub_key, priv_key)
            || !DH_set0_pqg(dh_priv, dh_p, NULL, dh_g)
            ) {
            if (dh_p) BN_free(dh_p);
            if (dh_g) BN_free(dh_g);
            if (other_pub_key) BN_free(other_pub_key);
            if (dummy_pub_key) BN_free(dummy_pub_key);
            if (priv_key) BN_free(priv_key);
            return enif_make_badarg(env);
        }
    }
    {
        ErlNifBinary ret_bin;
        int size;

        enif_alloc_binary(DH_size(dh_priv), &ret_bin);
        size = DH_compute_key(ret_bin.data, other_pub_key, dh_priv);
        BN_free(other_pub_key);
        DH_free(dh_priv);
        if (size<=0) {
            enif_release_binary(&ret_bin);
            return atom_error;
        }

        if (size != ret_bin.size) enif_realloc_binary(&ret_bin, size);
        return enif_make_binary(env, &ret_bin);
    }
}

tr_dh_secret_t
tr_dh_agree (tr_dh_ctx_t     handle,
             const uint8_t * other_public_key,
             size_t          other_public_key_length)
{
  struct tr_dh_secret * ret;
  int dh_size, secret_key_length;
  BIGNUM * other_key;

  assert (handle != NULL);
  assert (other_public_key != NULL);

  if (!check_pointer (other_key = BN_bin2bn (other_public_key, other_public_key_length, NULL)))
    return NULL;

  dh_size = DH_size (handle);
  ret = tr_dh_secret_new (dh_size);

  secret_key_length = DH_compute_key (ret->key, other_key, handle);
  if (check_result_neq (secret_key_length, -1))
    {
      tr_dh_secret_align (ret, secret_key_length);
    }
  else
    {
      tr_dh_secret_free (ret);
      ret = NULL;
    }

  BN_free (other_key);
  return ret;
}

	// Set the prime P and the generator, generate local public key
	DH_key_exchange::DH_key_exchange ()
	{
		m_DH = DH_new ();

		m_DH->p = BN_bin2bn (m_dh_prime, sizeof(m_dh_prime), NULL);
		m_DH->g = BN_bin2bn (m_dh_generator, sizeof(m_dh_generator), NULL);

		assert (sizeof(m_dh_prime) == DH_size(m_DH));
		
		DH_generate_key (m_DH); // TODO Check != 0

		assert (m_DH->pub_key);

		// DH can generate key sizes that are smaller than the size of
		// P with exponentially decreasing probability, in which case
		// the msb's of m_dh_local_key need to be zeroed
		// appropriately.
		int key_size = get_local_key_size();
		int len_dh = sizeof(m_dh_prime); // must equal DH_size(m_DH)
		if (key_size != len_dh)
		{
			assert(key_size > 0 && key_size < len_dh);

			int pad_zero_size = len_dh - key_size;
			std::fill(m_dh_local_key, m_dh_local_key + pad_zero_size, 0);
			BN_bn2bin(m_DH->pub_key, (unsigned char*)m_dh_local_key + pad_zero_size);
		}
		else
			BN_bn2bin(m_DH->pub_key, (unsigned char*)m_dh_local_key); // TODO Check return value
	}

struct sec performDH(char *pubkeyRec,DH *privkey){
	
	struct sec s;
	int secret_size;
	/* Send the public key to the peer.
	* How this occurs will be specific to your situation (see main text below) */


	/* Receive the public key from the peer. In this example we're just hard coding a value */
	BIGNUM *pubkey = NULL;
	if(0 == (BN_dec2bn(&pubkey, pubkeyRec))) handleErrors();

	/* Compute the shared secret */
	unsigned char *secret;
	if(NULL == (secret = OPENSSL_malloc(sizeof(unsigned char) * (DH_size(privkey))))) handleErrors();

	if(0 > (secret_size = DH_compute_key(secret, pubkey, privkey))) handleErrors();

	/* Do something with the shared secret */
	/* Note secret_size may be less than DH_size(privkey) */
	printf("The shared secret is:\n");
	
	strcpy(s.value,secret);
	s.length=secret_size;
	/* Clean up */
	OPENSSL_free(secret);
	BN_free(pubkey);
	DH_free(privkey);

	return s;
}

void openssl_dh_crypt()
{
	BIO *b;
	DH *d1, *d2;
	int i, len1, len2;
	unsigned char skey1[COMM_LEN], skey2[COMM_LEN];

	d1 = DH_new();
	d2 = DH_new();
	DH_generate_parameters_ex(d1, 64, DH_GENERATOR_2, NULL);
	DH_check(d1, &i);
	printf("\nDH key size: %d\n", DH_size(d1));
	DH_generate_key(d1);

	d2->p = BN_dup(d1->p);
	d2->g = BN_dup(d1->g);
	DH_generate_key(d2);
	DH_check_pub_key(d1, d1->pub_key, &i);
	len1 = DH_compute_key(skey1, d2->pub_key, d1);
	len2 = DH_compute_key(skey2, d1->pub_key, d2);
	if ((len1 != len2) || (memcmp(skey1, skey2, len1) != 0)) {
		printf("DH_compute_key err!\n");
		DH_free(d1);
		DH_free(d2);
		return;
	}

	b = BIO_new(BIO_s_file());
	BIO_set_fp(b, stdout, BIO_NOCLOSE);
	DHparams_print(b, d1);

	BIO_free(b);
	DH_free(d1);
	DH_free(d2);
}

const uint8_t*
tr_cryptoComputeSecret( tr_crypto *     crypto,
                        const uint8_t * peerPublicKey )
{
    int      len;
    uint8_t  secret[KEY_LEN];
    BIGNUM * bn = BN_bin2bn( peerPublicKey, KEY_LEN, NULL );
    DH *     dh;

    ensureKeyExists( crypto );
    dh = crypto->dh;

    assert( DH_size( dh ) == KEY_LEN );

    len = DH_compute_key( secret, bn, dh );
    if( len == -1 )
        logErrorFromSSL( );
    else {
        int offset;
        assert( len <= KEY_LEN );
        offset = KEY_LEN - len;
        memset( crypto->mySecret, 0, offset );
        memcpy( crypto->mySecret + offset, secret, len );
        crypto->mySecretIsSet = 1;
    }

    BN_free( bn );
    return crypto->mySecret;
}

int tr_compute_dh_key(unsigned char **pbuf,
		      BIGNUM *pub_key,
		      DH *priv_dh) {
  size_t buflen;
  unsigned char *buf = NULL;;
  int rc = 0;

  if ((!pbuf) ||
      (!pub_key) ||
      (!priv_dh)) {
    tr_debug("tr_compute_dh_key: Invalid parameters.");
    return(-1);
  }
  *pbuf = NULL;
  buflen = DH_size(priv_dh);
  buf = malloc(buflen);
  if (buf == NULL) {
    tr_crit("tr_compute_dh_key: out of memory");
    return -1;
  }


  rc = DH_compute_key(buf, pub_key, priv_dh);
  if (0 <= rc) {
    *pbuf = buf;
  }else {
    free(buf);
  }
  return rc;
}

std::string avjackif::async_client_hello(boost::asio::yield_context yield_context)
{
	proto::client_hello client_hello;
	client_hello.set_client("avim");
	client_hello.set_version(0001);

	unsigned char to[512];

	auto dh = DH_new();
	DH_generate_parameters_ex(dh,64,DH_GENERATOR_5,NULL);
	DH_generate_key(dh);

	// 把 g,p, pubkey 传过去
	client_hello.set_random_g((const void*)to, BN_bn2bin(dh->g, to));
	client_hello.set_random_p((const void*)to, BN_bn2bin(dh->p, to));
	client_hello.set_random_pub_key((const void*)to, BN_bn2bin(dh->pub_key, to));

	auto tobesend = av_router::encode(client_hello);

	boost::asio::async_write(*m_sock, boost::asio::buffer(tobesend), yield_context);

	// 解码
	std::unique_ptr<proto::server_hello> server_hello(
		(proto::server_hello*)async_read_protobuf_message(*m_sock, yield_context));

	m_remote_addr.reset(new proto::av_address(
		av_address_from_string(server_hello->server_av_address())));

	auto server_pubkey = BN_bin2bn((const unsigned char *) server_hello->random_pub_key().data(),
		server_hello->random_pub_key().length(), NULL);

	m_shared_key.resize(DH_size(dh));
	// 密钥就算出来啦！
	DH_compute_key(&m_shared_key[0], server_pubkey, dh);
	BN_free(server_pubkey);

    std::printf("key = 0x");
    for (int i=0; i<DH_size(dh); ++i)
	{
        std::printf("%x%x", (m_shared_key[i] >> 4) & 0xf, m_shared_key[i] & 0xf);
    }
    std::printf("\n");
	DH_free(dh);

	return server_hello->random_pub_key();
}

static krb5_error_code
generate_dh_keyblock(krb5_context context, pk_client_params *client_params,
                     krb5_enctype enctype, krb5_keyblock *reply_key)
{
    unsigned char *dh_gen_key = NULL;
    krb5_keyblock key;
    krb5_error_code ret;
    size_t dh_gen_keylen, size;

    memset(&key, 0, sizeof(key));

    if (!DH_generate_key(client_params->dh)) {
	ret = KRB5KRB_ERR_GENERIC;
	krb5_set_error_message(context, ret, "Can't generate Diffie-Hellman keys");
	goto out;
    }
    if (client_params->dh_public_key == NULL) {
	ret = KRB5KRB_ERR_GENERIC;
	krb5_set_error_message(context, ret, "dh_public_key");
	goto out;
    }

    dh_gen_keylen = DH_size(client_params->dh);
    size = BN_num_bytes(client_params->dh->p);
    if (size < dh_gen_keylen)
	size = dh_gen_keylen;

    dh_gen_key = malloc(size);
    if (dh_gen_key == NULL) {
	ret = ENOMEM;
	krb5_set_error_message(context, ret, "malloc: out of memory");
	goto out;
    }
    memset(dh_gen_key, 0, size - dh_gen_keylen);

    dh_gen_keylen = DH_compute_key(dh_gen_key + (size - dh_gen_keylen),
				   client_params->dh_public_key,
				   client_params->dh);
    if (dh_gen_keylen == -1) {
	ret = KRB5KRB_ERR_GENERIC;
	krb5_set_error_message(context, ret, "Can't compute Diffie-Hellman key");
	goto out;
    }

    ret = _krb5_pk_octetstring2key(context,
				   enctype,
				   dh_gen_key, dh_gen_keylen,
				   NULL, NULL,
				   reply_key);

 out:
    if (dh_gen_key)
	free(dh_gen_key);
    if (key.keyvalue.data)
	krb5_free_keyblock_contents(context, &key);

    return ret;
}

/*
 *	Generate an empheral DH key.  Because this can take a long
 *	time to compute, we can use precomputed parameters of the
 *	common key sizes.
 *
 *	Since few sites will bother to precompute these parameter
 *	files, we also provide a fallback to the parameters provided
 *	by the OpenSSL project.
 *
 *	These values can be static (once loaded or computed) since
 *	the OpenSSL library can efficiently generate random keys from
 *	the information provided.
 */
static DH  *
tmp_dh_cb(SSL *s, int is_export, int keylength)
{
	DH		   *r = NULL;
	static DH  *dh = NULL;
	static DH  *dh512 = NULL;
	static DH  *dh1024 = NULL;
	static DH  *dh2048 = NULL;
	static DH  *dh4096 = NULL;

	switch (keylength)
	{
		case 512:
			if (dh512 == NULL)
				dh512 = load_dh_file(keylength);
			if (dh512 == NULL)
				dh512 = load_dh_buffer(file_dh512, sizeof file_dh512);
			r = dh512;
			break;

		case 1024:
			if (dh1024 == NULL)
				dh1024 = load_dh_file(keylength);
			if (dh1024 == NULL)
				dh1024 = load_dh_buffer(file_dh1024, sizeof file_dh1024);
			r = dh1024;
			break;

		case 2048:
			if (dh2048 == NULL)
				dh2048 = load_dh_file(keylength);
			if (dh2048 == NULL)
				dh2048 = load_dh_buffer(file_dh2048, sizeof file_dh2048);
			r = dh2048;
			break;

		case 4096:
			if (dh4096 == NULL)
				dh4096 = load_dh_file(keylength);
			if (dh4096 == NULL)
				dh4096 = load_dh_buffer(file_dh4096, sizeof file_dh4096);
			r = dh4096;
			break;

		default:
			if (dh == NULL)
				dh = load_dh_file(keylength);
			r = dh;
	}

	/* this may take a long time, but it may be necessary... */
	if (r == NULL || 8 * DH_size(r) < keylength)
		r = DH_generate_parameters(keylength, DH_GENERATOR_2, NULL, NULL);

	return r;
}