C++ SymmetricKey::bits_of方法代码示例

SymmetricKey derive_key(const std::string& param,
                        const SymmetricKey& masterkey,
                        u32bit outputlength)
   {
   std::auto_ptr<KDF> kdf(get_kdf("KDF2(SHA-1)"));
   return kdf->derive_key(outputlength, masterkey.bits_of(), param);
   }

/*
* Create a new Client Key Exchange message
*/
Client_Key_Exchange::Client_Key_Exchange(Handshake_IO& io,
                                         Handshake_State& state,
                                         const Policy& policy,
                                         Credentials_Manager& creds,
                                         const Public_Key* server_public_key,
                                         const std::string& hostname,
                                         RandomNumberGenerator& rng)
   {
   const std::string kex_algo = state.ciphersuite().kex_algo();

   if(kex_algo == "PSK")
      {
      std::string identity_hint = "";

      if(state.server_kex())
         {
         TLS_Data_Reader reader("ClientKeyExchange", state.server_kex()->params());
         identity_hint = reader.get_string(2, 0, 65535);
         }

      const std::string psk_identity = creds.psk_identity("tls-client",
                                                          hostname,
                                                          identity_hint);

      append_tls_length_value(m_key_material, psk_identity, 2);

      SymmetricKey psk = creds.psk("tls-client", hostname, psk_identity);

      std::vector<byte> zeros(psk.length());

      append_tls_length_value(m_pre_master, zeros, 2);
      append_tls_length_value(m_pre_master, psk.bits_of(), 2);
      }
   else if(state.server_kex())
      {
      TLS_Data_Reader reader("ClientKeyExchange", state.server_kex()->params());

      SymmetricKey psk;

      if(kex_algo == "DHE_PSK" || kex_algo == "ECDHE_PSK")
         {
         std::string identity_hint = reader.get_string(2, 0, 65535);

         const std::string psk_identity = creds.psk_identity("tls-client",
                                                             hostname,
                                                             identity_hint);

         append_tls_length_value(m_key_material, psk_identity, 2);

         psk = creds.psk("tls-client", hostname, psk_identity);
         }

      if(kex_algo == "DH" || kex_algo == "DHE_PSK")
         {
         BigInt p = BigInt::decode(reader.get_range<byte>(2, 1, 65535));
         BigInt g = BigInt::decode(reader.get_range<byte>(2, 1, 65535));
         BigInt Y = BigInt::decode(reader.get_range<byte>(2, 1, 65535));

         if(reader.remaining_bytes())
            throw Decoding_Error("Bad params size for DH key exchange");

         if(p.bits() < policy.minimum_dh_group_size())
            throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
                                "Server sent DH group of " +
                                std::to_string(p.bits()) +
                                " bits, policy requires at least " +
                                std::to_string(policy.minimum_dh_group_size()));

         /*
         * A basic check for key validity. As we do not know q here we
         * cannot check that Y is in the right subgroup. However since
         * our key is ephemeral there does not seem to be any
         * advantage to bogus keys anyway.
         */
         if(Y <= 1 || Y >= p - 1)
            throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
                                "Server sent bad DH key for DHE exchange");

         DL_Group group(p, g);

         if(!group.verify_group(rng, false))
            throw TLS_Exception(Alert::INSUFFICIENT_SECURITY,
                                "DH group validation failed");

         DH_PublicKey counterparty_key(group, Y);

         DH_PrivateKey priv_key(rng, group);

         PK_Key_Agreement ka(priv_key, "Raw");

         secure_vector<byte> dh_secret = CT::strip_leading_zeros(
            ka.derive_key(0, counterparty_key.public_value()).bits_of());

         if(kex_algo == "DH")
            m_pre_master = dh_secret;
         else
            {
//.........这里部分代码省略.........

/*
* Read a Client Key Exchange message
*/
Client_Key_Exchange::Client_Key_Exchange(const std::vector<byte>& contents,
                                         const Handshake_State& state,
                                         const Private_Key* server_rsa_kex_key,
                                         Credentials_Manager& creds,
                                         const Policy& policy,
                                         RandomNumberGenerator& rng)
   {
   const std::string kex_algo = state.ciphersuite().kex_algo();

   if(kex_algo == "RSA")
      {
      BOTAN_ASSERT(state.server_certs() && !state.server_certs()->cert_chain().empty(),
                   "RSA key exchange negotiated so server sent a certificate");

      if(!server_rsa_kex_key)
         throw Internal_Error("Expected RSA kex but no server kex key set");

      if(!dynamic_cast<const RSA_PrivateKey*>(server_rsa_kex_key))
         throw Internal_Error("Expected RSA key but got " + server_rsa_kex_key->algo_name());

      PK_Decryptor_EME decryptor(*server_rsa_kex_key, "PKCS1v15");

      Protocol_Version client_version = state.client_hello()->version();

      /*
      * This is used as the pre-master if RSA decryption fails.
      * Otherwise we can be used as an oracle. See Bleichenbacher
      * "Chosen Ciphertext Attacks against Protocols Based on RSA
      * Encryption Standard PKCS #1", Crypto 98
      *
      * Create it here instead if in the catch clause as otherwise we
      * expose a timing channel WRT the generation of the fake value.
      * Some timing channel likely remains due to exception handling
      * and the like.
      */
      secure_vector<byte> fake_pre_master = rng.random_vec(48);
      fake_pre_master[0] = client_version.major_version();
      fake_pre_master[1] = client_version.minor_version();

      try
         {
         TLS_Data_Reader reader("ClientKeyExchange", contents);
         m_pre_master = decryptor.decrypt(reader.get_range<byte>(2, 0, 65535));

         if(m_pre_master.size() != 48 ||
            client_version.major_version() != m_pre_master[0] ||
            client_version.minor_version() != m_pre_master[1])
            {
            throw Decoding_Error("Client_Key_Exchange: Secret corrupted");
            }
         }
      catch(...)
         {
         m_pre_master = fake_pre_master;
         }
      }
   else
      {
      TLS_Data_Reader reader("ClientKeyExchange", contents);

      SymmetricKey psk;

      if(kex_algo == "PSK" || kex_algo == "DHE_PSK" || kex_algo == "ECDHE_PSK")
         {
         const std::string psk_identity = reader.get_string(2, 0, 65535);

         psk = creds.psk("tls-server",
                         state.client_hello()->sni_hostname(),
                         psk_identity);

         if(psk.length() == 0)
            {
            if(policy.hide_unknown_users())
               psk = SymmetricKey(rng, 16);
            else
               throw TLS_Exception(Alert::UNKNOWN_PSK_IDENTITY,
                                   "No PSK for identifier " + psk_identity);
            }
         }

      if(kex_algo == "PSK")
         {
         std::vector<byte> zeros(psk.length());
         append_tls_length_value(m_pre_master, zeros, 2);
         append_tls_length_value(m_pre_master, psk.bits_of(), 2);
         }
#if defined(BOTAN_HAS_SRP6)
      else if(kex_algo == "SRP_SHA")
         {
         SRP6_Server_Session& srp = state.server_kex()->server_srp_params();

         m_pre_master = srp.step2(BigInt::decode(reader.get_range<byte>(2, 0, 65535))).bits_of();
         }
#endif
      else if(kex_algo == "DH" || kex_algo == "DHE_PSK" ||
              kex_algo == "ECDH" || kex_algo == "ECDHE_PSK")
         {
//.........这里部分代码省略.........