ssl: Structural perarparation to support DTLS

Also phase in tls module as main API instead of ssl. To
make API clearer. As TLS is the new protocol name.
Maybe keep some API functions in ssl

1 files changed, 1827 insertions, 0 deletions

diff --git a/lib/ssl/src/tls_handshake.erl b/lib/ssl/src/tls_handshake.erl
new file mode 100644
index 0000000000..fea75736f7
--- /dev/null
+++ b/lib/ssl/src/tls_handshake.erl
@@ -0,0 +1,1827 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2007-2013. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%%----------------------------------------------------------------------
+%% Purpose: Help funtions for handling the SSL-handshake protocol
+%%----------------------------------------------------------------------
+
+-module(tls_handshake).
+
+-include("tls_handshake.hrl").
+-include("tls_record.hrl").
+-include("ssl_cipher.hrl").
+-include("ssl_alert.hrl").
+-include("ssl_internal.hrl").
+-include("ssl_srp.hrl").
+-include_lib("public_key/include/public_key.hrl").
+
+-export([master_secret/4, client_hello/8, server_hello/7, hello/4,
+	 hello_request/0, certify/7, certificate/4,
+	 client_certificate_verify/6, certificate_verify/6, verify_signature/5,
+	 certificate_request/3, key_exchange/3, server_key_exchange_hash/2,
+	 finished/5, verify_connection/6, get_tls_handshake/3,
+	 decode_client_key/3, decode_server_key/3, server_hello_done/0,
+	 encode_handshake/2, init_handshake_history/0, update_handshake_history/2,
+	 decrypt_premaster_secret/2, prf/5, next_protocol/1]).
+
+-export([dec_hello_extensions/2]).
+
+-type tls_handshake() :: #client_hello{} | #server_hello{} |
+			 #server_hello_done{} | #certificate{} | #certificate_request{} |
+			 #client_key_exchange{} | #finished{} | #certificate_verify{} |
+			 #hello_request{} | #next_protocol{}.
+
+-define(NAMED_CURVE_TYPE, 3).
+
+%%====================================================================
+%% Internal application API
+%%====================================================================
+%%--------------------------------------------------------------------
+-spec client_hello(host(), inet:port_number(), #connection_states{},
+		   #ssl_options{}, integer(), atom(), boolean(), der_cert()) ->
+			  #client_hello{}.
+%%
+%% Description: Creates a client hello message.
+%%--------------------------------------------------------------------
+client_hello(Host, Port, ConnectionStates,
+	     #ssl_options{versions = Versions,
+			  ciphers = UserSuites
+			 } = SslOpts,
+	     Cache, CacheCb, Renegotiation, OwnCert) ->
+    Version = tls_record:highest_protocol_version(Versions),
+    Pending = tls_record:pending_connection_state(ConnectionStates, read),
+    SecParams = Pending#connection_state.security_parameters,
+    Ciphers = available_suites(UserSuites, Version),
+    SRP = srp_user(SslOpts),
+    {EcPointFormats, EllipticCurves} = default_ecc_extensions(Version),
+
+    Id = ssl_session:client_id({Host, Port, SslOpts}, Cache, CacheCb, OwnCert),
+
+    #client_hello{session_id = Id,
+		  client_version = Version,
+		  cipher_suites = cipher_suites(Ciphers, Renegotiation),
+		  compression_methods = tls_record:compressions(),
+		  random = SecParams#security_parameters.client_random,
+
+		  renegotiation_info =
+		      renegotiation_info(client, ConnectionStates, Renegotiation),
+		  srp = SRP,
+		  hash_signs = default_hash_signs(),
+		  ec_point_formats = EcPointFormats,
+		  elliptic_curves = EllipticCurves,
+		  next_protocol_negotiation =
+		      encode_client_protocol_negotiation(SslOpts#ssl_options.next_protocol_selector, Renegotiation)
+		 }.
+
+encode_protocol(Protocol, Acc) ->
+	Len = byte_size(Protocol),
+	<<Acc/binary, ?BYTE(Len), Protocol/binary>>.
+
+encode_protocols_advertised_on_server(undefined) ->
+	undefined;
+
+encode_protocols_advertised_on_server(Protocols) ->
+	#next_protocol_negotiation{extension_data = lists:foldl(fun encode_protocol/2, <<>>, Protocols)}.
+
+%%--------------------------------------------------------------------
+-spec server_hello(session_id(), tls_version(), #connection_states{}, 
+		   boolean(), [binary()] | undefined,
+		   #ec_point_formats{} | undefined,
+		   #elliptic_curves{} | undefined) -> #server_hello{}.
+%%
+%% Description: Creates a server hello message.
+%%--------------------------------------------------------------------
+server_hello(SessionId, Version, ConnectionStates, Renegotiation,
+	     ProtocolsAdvertisedOnServer, EcPointFormats, EllipticCurves) ->
+    Pending = tls_record:pending_connection_state(ConnectionStates, read),
+    SecParams = Pending#connection_state.security_parameters,
+    #server_hello{server_version = Version,
+		  cipher_suite = SecParams#security_parameters.cipher_suite,
+                  compression_method = 
+		  SecParams#security_parameters.compression_algorithm,
+		  random = SecParams#security_parameters.server_random,
+		  session_id = SessionId,
+		  renegotiation_info = 
+		  renegotiation_info(server, ConnectionStates, Renegotiation),
+		  ec_point_formats = EcPointFormats,
+		  elliptic_curves = EllipticCurves,
+		  next_protocol_negotiation = encode_protocols_advertised_on_server(ProtocolsAdvertisedOnServer)
+		 }.
+
+%%--------------------------------------------------------------------
+-spec hello_request() -> #hello_request{}.
+%%
+%% Description: Creates a hello request message sent by server to 
+%% trigger renegotiation.
+%%--------------------------------------------------------------------
+hello_request() ->
+    #hello_request{}.
+
+%%--------------------------------------------------------------------
+-spec hello(#server_hello{} | #client_hello{}, #ssl_options{},
+	    #connection_states{} | {inet:port_number(), #session{}, db_handle(),
+				    atom(), #connection_states{}, binary()},
+	    boolean()) ->
+			  {tls_version(), session_id(), #connection_states{}, binary() | undefined}|
+			  {tls_version(), {resumed | new, #session{}}, #connection_states{}, [binary()] | undefined,
+			  [oid()] | undefined, [oid()] | undefined} |
+			  #alert{}.
+%%
+%% Description: Handles a recieved hello message
+%%--------------------------------------------------------------------
+hello(#server_hello{cipher_suite = CipherSuite, server_version = Version,
+		    compression_method = Compression, random = Random,
+		    session_id = SessionId, renegotiation_info = Info,
+		    hash_signs = _HashSigns} = Hello,
+      #ssl_options{secure_renegotiate = SecureRenegotation, next_protocol_selector = NextProtocolSelector,
+		   versions = SupportedVersions},
+      ConnectionStates0, Renegotiation) ->
+    %%TODO: select hash and signature algorigthm
+    case tls_record:is_acceptable_version(Version, SupportedVersions) of
+	true ->
+	    case handle_renegotiation_info(client, Info, ConnectionStates0, 
+					   Renegotiation, SecureRenegotation, []) of
+		{ok, ConnectionStates1} ->
+		    ConnectionStates =
+			hello_pending_connection_states(client, Version, CipherSuite, Random,
+							Compression, ConnectionStates1),
+		    case handle_next_protocol(Hello, NextProtocolSelector, Renegotiation) of
+			#alert{} = Alert ->
+			    Alert;
+			    Protocol ->
+			    {Version, SessionId, ConnectionStates, Protocol}
+		    end;
+		#alert{} = Alert ->
+		    Alert
+	    end;
+	false ->
+	    ?ALERT_REC(?FATAL, ?PROTOCOL_VERSION)
+    end;
+			       
+hello(#client_hello{client_version = ClientVersion} = Hello,
+      #ssl_options{versions = Versions} = SslOpts,
+      {Port, Session0, Cache, CacheCb, ConnectionStates0, Cert}, Renegotiation) ->
+    %% TODO: select hash and signature algorithm
+    Version = select_version(ClientVersion, Versions),
+    case tls_record:is_acceptable_version(Version, Versions) of
+	true ->
+	    %% TODO: need to take supported Curves into Account when selecting the CipherSuite....
+	    %%       if whe have an ECDSA cert with an unsupported curve, we need to drop ECDSA ciphers
+	    {Type, #session{cipher_suite = CipherSuite} = Session1}
+		= select_session(Hello, Port, Session0, Version, 
+				 SslOpts, Cache, CacheCb, Cert),
+	    case CipherSuite of 
+		no_suite ->
+		    ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY);
+		_ ->
+		    try handle_hello_extensions(Hello, Version, SslOpts, Session1, ConnectionStates0, Renegotiation) of
+			{Session, ConnectionStates, ProtocolsToAdvertise, ECPointFormats, EllipticCurves} ->
+			    {Version, {Type, Session}, ConnectionStates,
+			     ProtocolsToAdvertise, ECPointFormats, EllipticCurves}
+		    catch throw:Alert ->
+			    Alert
+		    end
+	    end;
+	false ->
+	    ?ALERT_REC(?FATAL, ?PROTOCOL_VERSION)
+    end.
+
+%%--------------------------------------------------------------------
+-spec certify(#certificate{}, db_handle(), certdb_ref(), integer() | nolimit,
+	      verify_peer | verify_none, {fun(), term},
+	      client | server) ->  {der_cert(), public_key_info()} | #alert{}.
+%%
+%% Description: Handles a certificate handshake message
+%%--------------------------------------------------------------------
+certify(#certificate{asn1_certificates = ASN1Certs}, CertDbHandle, CertDbRef,
+	MaxPathLen, _Verify, VerifyFunAndState, Role) ->
+    [PeerCert | _] = ASN1Certs,
+      
+    ValidationFunAndState =
+	case VerifyFunAndState of
+	    undefined ->
+		{fun(OtpCert, ExtensionOrVerifyResult, SslState) ->
+			 ssl_certificate:validate_extension(OtpCert,
+							    ExtensionOrVerifyResult, SslState)
+		 end, Role};
+	    {Fun, UserState0} ->
+		{fun(OtpCert, {extension, _} = Extension, {SslState, UserState}) ->
+			 case ssl_certificate:validate_extension(OtpCert,
+								 Extension,
+								 SslState) of
+			     {valid, NewSslState} ->
+				 {valid, {NewSslState, UserState}};
+			     {fail, Reason} ->
+				 apply_user_fun(Fun, OtpCert, Reason, UserState,
+						SslState);
+			     {unknown, _} ->
+				 apply_user_fun(Fun, OtpCert,
+						Extension, UserState, SslState)
+			 end;
+		    (OtpCert, VerifyResult, {SslState, UserState}) ->
+			 apply_user_fun(Fun, OtpCert, VerifyResult, UserState,
+					SslState)
+		 end, {Role, UserState0}}
+	end,
+
+    try
+	{TrustedErlCert, CertPath}  =
+	    ssl_certificate:trusted_cert_and_path(ASN1Certs, CertDbHandle, CertDbRef),
+	case public_key:pkix_path_validation(TrustedErlCert,
+					      CertPath,
+					     [{max_path_length,
+					       MaxPathLen},
+					      {verify_fun, ValidationFunAndState}]) of
+	    {ok, {PublicKeyInfo,_}} ->
+		{PeerCert, PublicKeyInfo};
+	    {error, Reason} ->
+		path_validation_alert(Reason)
+	end
+    catch
+	error:_ ->
+	    %% ASN-1 decode of certificate somehow failed
+	    ?ALERT_REC(?FATAL, ?CERTIFICATE_UNKNOWN)
+    end.
+
+%%--------------------------------------------------------------------
+-spec certificate(der_cert(), db_handle(), certdb_ref(), client | server) -> #certificate{} | #alert{}.
+%%
+%% Description: Creates a certificate message.
+%%--------------------------------------------------------------------
+certificate(OwnCert, CertDbHandle, CertDbRef, client) ->
+    Chain =
+	case ssl_certificate:certificate_chain(OwnCert, CertDbHandle, CertDbRef) of
+	    {ok, CertChain} ->
+		CertChain;
+	    {error, _} -> 
+		%% If no suitable certificate is available, the client
+		%% SHOULD send a certificate message containing no
+		%% certificates. (chapter 7.4.6. RFC 4346)
+		[]	 
+	end,
+    #certificate{asn1_certificates = Chain};
+
+certificate(OwnCert, CertDbHandle, CertDbRef, server) ->
+    case ssl_certificate:certificate_chain(OwnCert, CertDbHandle, CertDbRef) of
+	{ok, Chain} ->
+	    #certificate{asn1_certificates = Chain};
+	{error, _} ->
+	    ?ALERT_REC(?FATAL, ?INTERNAL_ERROR)
+    end.
+
+%%--------------------------------------------------------------------
+-spec client_certificate_verify(undefined | der_cert(), binary(),
+				tls_version(), term(), private_key(),
+				tls_handshake_history()) ->
+    #certificate_verify{} | ignore | #alert{}.
+%%
+%% Description: Creates a certificate_verify message, called by the client.
+%%--------------------------------------------------------------------
+client_certificate_verify(undefined, _, _, _, _, _) ->
+    ignore;
+client_certificate_verify(_, _, _, _, undefined, _) ->
+    ignore;
+client_certificate_verify(OwnCert, MasterSecret, Version,
+			  {HashAlgo, SignAlgo},
+			  PrivateKey, {Handshake, _}) ->
+    case public_key:pkix_is_fixed_dh_cert(OwnCert) of
+	true ->
+	    ?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE);
+	false ->
+	    Hashes =
+		calc_certificate_verify(Version, HashAlgo, MasterSecret, Handshake),
+	    Signed = digitally_signed(Version, Hashes, HashAlgo, PrivateKey),
+	    #certificate_verify{signature = Signed, hashsign_algorithm = {HashAlgo, SignAlgo}}
+    end.
+
+%%--------------------------------------------------------------------
+-spec certificate_verify(binary(), public_key_info(), tls_version(), term(),
+			 binary(), tls_handshake_history()) -> valid | #alert{}.
+%%
+%% Description: Checks that the certificate_verify message is valid.
+%%--------------------------------------------------------------------
+certificate_verify(Signature, PublicKeyInfo, Version,
+		   HashSign = {HashAlgo, _}, MasterSecret, {_, Handshake}) ->
+    Hash = calc_certificate_verify(Version, HashAlgo, MasterSecret, Handshake),
+    case verify_signature(Version, Hash, HashSign, Signature, PublicKeyInfo) of
+	true ->
+	    valid;
+	_ ->
+    	    ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE)
+    end.
+
+%%--------------------------------------------------------------------
+-spec verify_signature(tls_version(), binary(), {term(), term()}, binary(),
+				   public_key_info()) -> true | false.
+%%
+%% Description: Checks that a public_key signature is valid.
+%%--------------------------------------------------------------------
+verify_signature(_Version, _Hash, {_HashAlgo, anon}, _Signature, _) ->
+    true;
+verify_signature({3, Minor}, Hash, {HashAlgo, rsa}, Signature, {?rsaEncryption, PubKey, _PubKeyParams})
+  when Minor >= 3 ->
+    public_key:verify({digest, Hash}, HashAlgo, Signature, PubKey);
+verify_signature(_Version, Hash, _HashAlgo, Signature, {?rsaEncryption, PubKey, _PubKeyParams}) ->
+    case public_key:decrypt_public(Signature, PubKey,
+				   [{rsa_pad, rsa_pkcs1_padding}]) of
+	Hash -> true;
+	_    -> false
+    end;
+verify_signature(_Version, Hash, {HashAlgo, dsa}, Signature, {?'id-dsa', PublicKey, PublicKeyParams}) ->
+    public_key:verify({digest, Hash}, HashAlgo, Signature, {PublicKey, PublicKeyParams});
+verify_signature(_Version, Hash, {HashAlgo, ecdsa}, Signature, {?'id-ecPublicKey', PublicKey, PublicKeyParams}) ->
+    public_key:verify({digest, Hash}, HashAlgo, Signature, {PublicKey, PublicKeyParams}).
+
+%%--------------------------------------------------------------------
+-spec certificate_request(#connection_states{}, db_handle(), certdb_ref()) ->
+    #certificate_request{}.
+%%
+%% Description: Creates a certificate_request message, called by the server.
+%%--------------------------------------------------------------------
+certificate_request(ConnectionStates, CertDbHandle, CertDbRef) ->
+    #connection_state{security_parameters = 
+		      #security_parameters{cipher_suite = CipherSuite}} =
+	tls_record:pending_connection_state(ConnectionStates, read),
+    Types = certificate_types(CipherSuite),
+    HashSigns = default_hash_signs(),
+    Authorities = certificate_authorities(CertDbHandle, CertDbRef),
+    #certificate_request{
+		    certificate_types = Types,
+		    hashsign_algorithms = HashSigns,
+		    certificate_authorities = Authorities
+		   }.
+
+%%--------------------------------------------------------------------
+-spec key_exchange(client | server, tls_version(),
+		   {premaster_secret, binary(), public_key_info()} |
+		   {dh, binary()} |
+		   {dh, {binary(), binary()}, #'DHParameter'{}, {HashAlgo::atom(), SignAlgo::atom()},
+		   binary(), binary(), private_key()} |
+		   {ecdh, #'ECPrivateKey'{}} |
+		   {psk, binary()} |
+		   {dhe_psk, binary(), binary()} |
+		   {srp, {binary(), binary()}, #srp_user{}, {HashAlgo::atom(), SignAlgo::atom()},
+		   binary(), binary(), private_key()}) ->
+    #client_key_exchange{} | #server_key_exchange{}.
+%%
+%% Description: Creates a keyexchange message.
+%%--------------------------------------------------------------------
+key_exchange(client, _Version, {premaster_secret, Secret, {_, PublicKey, _}}) ->
+    EncPremasterSecret =
+	encrypted_premaster_secret(Secret, PublicKey),
+    #client_key_exchange{exchange_keys = EncPremasterSecret};
+
+key_exchange(client, _Version, {dh, PublicKey}) ->
+    #client_key_exchange{
+	      exchange_keys = #client_diffie_hellman_public{
+		dh_public = PublicKey}
+	       };
+
+key_exchange(client, _Version, {ecdh, #'ECPrivateKey'{publicKey = {0, ECPublicKey}}}) ->
+    #client_key_exchange{
+	      exchange_keys = #client_ec_diffie_hellman_public{
+		dh_public = ECPublicKey}
+	       };
+
+key_exchange(client, _Version, {psk, Identity}) ->
+    #client_key_exchange{
+	      exchange_keys = #client_psk_identity{
+		identity = Identity}
+	       };
+
+key_exchange(client, _Version, {dhe_psk, Identity, PublicKey}) ->
+    #client_key_exchange{
+	      exchange_keys = #client_dhe_psk_identity{
+		identity = Identity,
+		dh_public = PublicKey}
+	       };
+
+key_exchange(client, _Version, {psk_premaster_secret, PskIdentity, Secret, {_, PublicKey, _}}) ->
+    EncPremasterSecret =
+	encrypted_premaster_secret(Secret, PublicKey),
+    #client_key_exchange{
+		exchange_keys = #client_rsa_psk_identity{
+				   identity = PskIdentity,
+		  exchange_keys = EncPremasterSecret}};
+
+key_exchange(client, _Version, {srp, PublicKey}) ->
+    #client_key_exchange{
+	      exchange_keys = #client_srp_public{
+		srp_a = PublicKey}
+	       };
+
+key_exchange(server, Version, {dh, {PublicKey, _},
+			       #'DHParameter'{prime = P, base = G},
+			       HashSign, ClientRandom, ServerRandom, PrivateKey}) ->
+    ServerDHParams = #server_dh_params{dh_p = int_to_bin(P),
+				       dh_g = int_to_bin(G), dh_y = PublicKey},
+    enc_server_key_exchange(Version, ServerDHParams, HashSign,
+			    ClientRandom, ServerRandom, PrivateKey);
+
+key_exchange(server, Version, {ecdh,  #'ECPrivateKey'{publicKey =  {0, ECPublicKey},
+						      parameters = ECCurve}, HashSign, ClientRandom, ServerRandom,
+	     PrivateKey}) ->
+    ServerECParams = #server_ecdh_params{curve = ECCurve, public = ECPublicKey},
+    enc_server_key_exchange(Version, ServerECParams, HashSign,
+			    ClientRandom, ServerRandom, PrivateKey);
+
+key_exchange(server, Version, {psk, PskIdentityHint,
+			       HashSign, ClientRandom, ServerRandom, PrivateKey}) ->
+    ServerPSKParams = #server_psk_params{hint = PskIdentityHint},
+    enc_server_key_exchange(Version, ServerPSKParams, HashSign,
+			    ClientRandom, ServerRandom, PrivateKey);
+
+key_exchange(server, Version, {dhe_psk, PskIdentityHint, {PublicKey, _},
+			       #'DHParameter'{prime = P, base = G},
+			       HashSign, ClientRandom, ServerRandom, PrivateKey}) ->
+    ServerEDHPSKParams = #server_dhe_psk_params{
+      hint = PskIdentityHint,
+      dh_params = #server_dh_params{dh_p = int_to_bin(P),
+				    dh_g = int_to_bin(G), dh_y = PublicKey}
+     },
+    enc_server_key_exchange(Version, ServerEDHPSKParams,
+			    HashSign, ClientRandom, ServerRandom, PrivateKey);
+
+key_exchange(server, Version, {srp, {PublicKey, _},
+			       #srp_user{generator = Generator, prime = Prime,
+					 salt = Salt},
+			       HashSign, ClientRandom, ServerRandom, PrivateKey}) ->
+    ServerSRPParams = #server_srp_params{srp_n = Prime, srp_g = Generator,
+					 srp_s = Salt, srp_b = PublicKey},
+    enc_server_key_exchange(Version, ServerSRPParams, HashSign,
+			    ClientRandom, ServerRandom, PrivateKey).
+
+enc_server_key_exchange(Version, Params, {HashAlgo, SignAlgo},
+			ClientRandom, ServerRandom, PrivateKey) ->
+    EncParams = enc_server_key(Params),
+    case HashAlgo of
+	null ->
+	    #server_key_params{params = Params,
+			       params_bin = EncParams,
+			       hashsign = {null, anon},
+			       signature = <<>>};
+	_ ->
+	    Hash =
+		server_key_exchange_hash(HashAlgo, <<ClientRandom/binary,
+						     ServerRandom/binary,
+						     EncParams/binary>>),
+	    Signature = digitally_signed(Version, Hash, HashAlgo, PrivateKey),
+	    #server_key_params{params = Params,
+			       params_bin = EncParams,
+			       hashsign = {HashAlgo, SignAlgo},
+			       signature = Signature}
+    end.
+
+%%--------------------------------------------------------------------
+-spec master_secret(tls_version(), #session{} | binary(), #connection_states{},
+		   client | server) -> {binary(), #connection_states{}} | #alert{}.
+%%    
+%% Description: Sets or calculates the master secret and calculate keys,
+%% updating the pending connection states. The Mastersecret and the update
+%% connection states are returned or an alert if the calculation fails.
+%%-------------------------------------------------------------------
+master_secret(Version, #session{master_secret = Mastersecret}, 
+	      ConnectionStates, Role) ->
+    ConnectionState = 
+	tls_record:pending_connection_state(ConnectionStates, read),
+    SecParams = ConnectionState#connection_state.security_parameters,
+    try master_secret(Version, Mastersecret, SecParams, 
+		      ConnectionStates, Role)
+    catch
+	exit:Reason ->
+	    Report = io_lib:format("Key calculation failed due to ~p",
+				   [Reason]),
+	    error_logger:error_report(Report),
+	    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE)
+    end;
+
+master_secret(Version, PremasterSecret, ConnectionStates, Role) ->
+    ConnectionState = 
+	tls_record:pending_connection_state(ConnectionStates, read),
+    SecParams = ConnectionState#connection_state.security_parameters,
+    #security_parameters{prf_algorithm = PrfAlgo,
+			 client_random = ClientRandom,
+			 server_random = ServerRandom} = SecParams, 
+    try master_secret(Version, 
+		      calc_master_secret(Version,PrfAlgo,PremasterSecret,
+				       ClientRandom, ServerRandom),
+		      SecParams, ConnectionStates, Role) 
+    catch
+	exit:Reason ->
+	    Report = io_lib:format("Master secret calculation failed"
+				   " due to ~p", [Reason]),
+	    error_logger:error_report(Report),
+	    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE)
+    end.
+
+-spec next_protocol(binary()) -> #next_protocol{}.
+
+next_protocol(SelectedProtocol) ->
+  #next_protocol{selected_protocol = SelectedProtocol}.
+
+%%--------------------------------------------------------------------
+-spec finished(tls_version(), client | server, integer(), binary(), tls_handshake_history()) ->
+    #finished{}.
+%%
+%% Description: Creates a handshake finished message
+%%-------------------------------------------------------------------
+finished(Version, Role, PrfAlgo, MasterSecret, {Handshake, _}) -> % use the current handshake
+    #finished{verify_data = 
+	      calc_finished(Version, Role, PrfAlgo, MasterSecret, Handshake)}.
+
+%%--------------------------------------------------------------------
+-spec verify_connection(tls_version(), #finished{}, client | server, integer(), binary(),
+			tls_handshake_history()) -> verified | #alert{}.
+%%
+%% Description: Checks the ssl handshake finished message to verify
+%%              the connection.
+%%-------------------------------------------------------------------
+verify_connection(Version, #finished{verify_data = Data}, 
+		  Role, PrfAlgo, MasterSecret, {_, Handshake}) ->
+    %% use the previous hashes
+    case calc_finished(Version, Role, PrfAlgo, MasterSecret, Handshake) of
+	Data ->
+	    verified;
+	_ ->
+	    ?ALERT_REC(?FATAL, ?DECRYPT_ERROR)
+    end.
+%%--------------------------------------------------------------------
+-spec server_hello_done() ->  #server_hello_done{}.
+%%     
+%% Description: Creates a server hello done message.
+%%--------------------------------------------------------------------	    
+server_hello_done() ->
+    #server_hello_done{}.
+
+%%--------------------------------------------------------------------
+-spec encode_handshake(tls_handshake(), tls_version()) -> iolist().
+%%     
+%% Description: Encode a handshake packet to binary
+%%--------------------------------------------------------------------x
+encode_handshake(Package, Version) ->
+    {MsgType, Bin} = enc_hs(Package, Version),
+    Len = byte_size(Bin),
+    [MsgType, ?uint24(Len), Bin].
+
+%%--------------------------------------------------------------------
+-spec get_tls_handshake(tls_version(), binary(), binary() | iolist()) ->
+     {[tls_handshake()], binary()}.
+%%
+%% Description: Given buffered and new data from ssl_record, collects
+%% and returns it as a list of handshake messages, also returns leftover
+%% data.
+%%--------------------------------------------------------------------
+get_tls_handshake(Version, Data, <<>>) ->
+    get_tls_handshake_aux(Version, Data, []);
+get_tls_handshake(Version, Data, Buffer) ->
+    get_tls_handshake_aux(Version, list_to_binary([Buffer, Data]), []).
+
+%%--------------------------------------------------------------------
+-spec decode_client_key(binary(), key_algo(), tls_version()) ->
+			    #encrypted_premaster_secret{}
+			    | #client_diffie_hellman_public{}
+			    | #client_ec_diffie_hellman_public{}
+			    | #client_psk_identity{}
+			    | #client_dhe_psk_identity{}
+			    | #client_rsa_psk_identity{}
+			    | #client_srp_public{}.
+%%
+%% Description: Decode client_key data and return appropriate type
+%%--------------------------------------------------------------------
+decode_client_key(ClientKey, Type, Version) ->
+    dec_client_key(ClientKey, key_exchange_alg(Type), Version).
+
+%%--------------------------------------------------------------------
+-spec decode_server_key(binary(), key_algo(), tls_version()) ->
+			       #server_key_params{}.
+%%
+%% Description: Decode server_key data and return appropriate type
+%%--------------------------------------------------------------------
+decode_server_key(ServerKey, Type, Version) ->
+    dec_server_key(ServerKey, key_exchange_alg(Type), Version).
+
+%%--------------------------------------------------------------------
+-spec init_handshake_history() -> tls_handshake_history().
+
+%%
+%% Description: Initialize the empty handshake history buffer.
+%%--------------------------------------------------------------------
+init_handshake_history() ->
+    {[], []}.
+
+%%--------------------------------------------------------------------
+-spec update_handshake_history(tls_handshake_history(), Data ::term()) ->
+				      tls_handshake_history().
+%%
+%% Description: Update the handshake history buffer with Data.
+%%--------------------------------------------------------------------
+update_handshake_history(Handshake, % special-case SSL2 client hello
+			 <<?CLIENT_HELLO, ?UINT24(_), ?BYTE(Major), ?BYTE(Minor),
+			   ?UINT16(CSLength), ?UINT16(0),
+			   ?UINT16(CDLength),
+			   CipherSuites:CSLength/binary,
+			   ChallengeData:CDLength/binary>>) ->
+    update_handshake_history(Handshake,
+			     <<?CLIENT_HELLO, ?BYTE(Major), ?BYTE(Minor),
+			       ?UINT16(CSLength), ?UINT16(0),
+			       ?UINT16(CDLength),
+			       CipherSuites:CSLength/binary,
+			       ChallengeData:CDLength/binary>>);
+update_handshake_history({Handshake0, _Prev}, Data) ->
+    {[Data|Handshake0], Handshake0}.
+
+%%--------------------------------------------------------------------
+-spec decrypt_premaster_secret(binary(), #'RSAPrivateKey'{}) -> binary().
+
+%%
+%% Description: Public key decryption using the private key.
+%%--------------------------------------------------------------------
+decrypt_premaster_secret(Secret, RSAPrivateKey) ->
+    try public_key:decrypt_private(Secret, RSAPrivateKey,
+				   [{rsa_pad, rsa_pkcs1_padding}])
+    catch
+	_:_ ->
+			io:format("decrypt_premaster_secret error"),
+	    throw(?ALERT_REC(?FATAL, ?DECRYPT_ERROR))
+    end.
+
+%%--------------------------------------------------------------------
+-spec server_key_exchange_hash(md5sha | md5 | sha | sha224 |sha256 | sha384 | sha512, binary()) -> binary().
+%%
+%% Description: Calculate server key exchange hash
+%%--------------------------------------------------------------------
+server_key_exchange_hash(md5sha, Value) ->
+    MD5 = crypto:hash(md5, Value),
+    SHA = crypto:hash(sha, Value),
+    <<MD5/binary, SHA/binary>>;
+
+server_key_exchange_hash(Hash, Value) ->
+    crypto:hash(Hash, Value).
+
+%%--------------------------------------------------------------------
+-spec prf(tls_version(), binary(), binary(), [binary()], non_neg_integer()) ->
+		 {ok, binary()} | {error, undefined}.
+%%
+%% Description: use the TLS PRF to generate key material
+%%--------------------------------------------------------------------
+prf({3,0}, _, _, _, _) ->
+    {error, undefined};
+prf({3,1}, Secret, Label, Seed, WantedLength) ->
+    {ok, ssl_tls1:prf(?MD5SHA, Secret, Label, Seed, WantedLength)};
+prf({3,_N}, Secret, Label, Seed, WantedLength) ->
+    {ok, ssl_tls1:prf(?SHA256, Secret, Label, Seed, WantedLength)}.
+
+%%--------------------------------------------------------------------
+%%% Internal functions
+%%--------------------------------------------------------------------
+get_tls_handshake_aux(Version, <<?BYTE(Type), ?UINT24(Length),
+			Body:Length/binary,Rest/binary>>, Acc) ->
+    Raw = <<?BYTE(Type), ?UINT24(Length), Body/binary>>,
+    H = dec_hs(Version, Type, Body),
+    get_tls_handshake_aux(Version, Rest, [{H,Raw} | Acc]);
+get_tls_handshake_aux(_Version, Data, Acc) ->
+    {lists:reverse(Acc), Data}.
+
+path_validation_alert({bad_cert, cert_expired}) ->
+    ?ALERT_REC(?FATAL, ?CERTIFICATE_EXPIRED);
+path_validation_alert({bad_cert, invalid_issuer}) ->
+    ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE);
+path_validation_alert({bad_cert, invalid_signature}) ->
+    ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE);
+path_validation_alert({bad_cert, name_not_permitted}) ->
+    ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE);
+path_validation_alert({bad_cert, unknown_critical_extension}) ->
+    ?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE);
+path_validation_alert({bad_cert, cert_revoked}) ->
+    ?ALERT_REC(?FATAL, ?CERTIFICATE_REVOKED);
+path_validation_alert({bad_cert, selfsigned_peer}) ->
+    ?ALERT_REC(?FATAL, ?BAD_CERTIFICATE);
+path_validation_alert({bad_cert, unknown_ca}) ->
+     ?ALERT_REC(?FATAL, ?UNKNOWN_CA);
+path_validation_alert(_) ->
+    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE).
+
+select_session(Hello, Port, Session, Version,
+	       #ssl_options{ciphers = UserSuites} = SslOpts, Cache, CacheCb, Cert) ->
+    SuggestedSessionId = Hello#client_hello.session_id,
+    {SessionId, Resumed} = ssl_session:server_id(Port, SuggestedSessionId,
+						 SslOpts, Cert,
+						 Cache, CacheCb),
+    Suites = available_suites(Cert, UserSuites, Version),
+    case Resumed of
+        undefined ->
+	    CipherSuite = select_cipher_suite(Hello#client_hello.cipher_suites, Suites),
+	    Compressions = Hello#client_hello.compression_methods,
+	    Compression = select_compression(Compressions),
+	    {new, Session#session{session_id = SessionId,
+				  cipher_suite = CipherSuite,
+				  compression_method = Compression}};
+	_ ->
+	    {resumed, Resumed}
+    end.
+
+available_suites(UserSuites, Version) ->
+    case UserSuites of
+	[] ->
+	    ssl_cipher:suites(Version);
+	_ ->
+	    UserSuites
+    end.
+
+available_suites(ServerCert, UserSuites, Version) ->
+    ssl_cipher:filter(ServerCert, available_suites(UserSuites, Version)).
+ 
+cipher_suites(Suites, false) ->
+    [?TLS_EMPTY_RENEGOTIATION_INFO_SCSV | Suites];
+cipher_suites(Suites, true) ->
+    Suites.
+
+srp_user(#ssl_options{srp_identity = {UserName, _}}) ->
+    #srp{username = UserName};
+srp_user(_) ->
+    undefined.
+
+renegotiation_info(client, _, false) ->
+    #renegotiation_info{renegotiated_connection = undefined};
+renegotiation_info(server, ConnectionStates, false) ->
+    CS  = tls_record:current_connection_state(ConnectionStates, read),
+    case CS#connection_state.secure_renegotiation of
+	true ->
+	    #renegotiation_info{renegotiated_connection = ?byte(0)};
+	false ->
+	    #renegotiation_info{renegotiated_connection = undefined}
+    end;
+renegotiation_info(client, ConnectionStates, true) ->
+    CS = tls_record:current_connection_state(ConnectionStates, read),
+    case CS#connection_state.secure_renegotiation of
+	true ->
+	    Data = CS#connection_state.client_verify_data,
+	    #renegotiation_info{renegotiated_connection = Data};
+	false ->
+	    #renegotiation_info{renegotiated_connection = undefined}
+    end;
+
+renegotiation_info(server, ConnectionStates, true) ->
+    CS = tls_record:current_connection_state(ConnectionStates, read),
+    case CS#connection_state.secure_renegotiation of
+	true ->
+	    CData = CS#connection_state.client_verify_data,
+	    SData  =CS#connection_state.server_verify_data,
+	    #renegotiation_info{renegotiated_connection = <<CData/binary, SData/binary>>};
+	false ->
+	    #renegotiation_info{renegotiated_connection = undefined}
+    end. 
+
+decode_next_protocols({next_protocol_negotiation, Protocols}) ->
+    decode_next_protocols(Protocols, []).
+decode_next_protocols(<<>>, Acc) ->
+    lists:reverse(Acc);
+decode_next_protocols(<<?BYTE(Len), Protocol:Len/binary, Rest/binary>>, Acc) ->
+    case Len of
+        0 ->
+            {error, invalid_next_protocols};
+        _ ->
+            decode_next_protocols(Rest, [Protocol|Acc])
+    end;
+decode_next_protocols(_Bytes, _Acc) ->
+    {error, invalid_next_protocols}.
+
+next_protocol_extension_allowed(NextProtocolSelector, Renegotiating) ->
+    NextProtocolSelector =/= undefined andalso not Renegotiating.
+
+handle_next_protocol_on_server(#client_hello{next_protocol_negotiation = undefined}, _Renegotiation, _SslOpts) ->
+    undefined;
+
+handle_next_protocol_on_server(#client_hello{next_protocol_negotiation = {next_protocol_negotiation, <<>>}},
+			       false, #ssl_options{next_protocols_advertised = Protocols}) ->
+    Protocols;
+
+handle_next_protocol_on_server(_Hello, _Renegotiation, _SSLOpts) ->
+    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE). % unexpected next protocol extension
+
+handle_next_protocol(#server_hello{next_protocol_negotiation = undefined},
+    _NextProtocolSelector, _Renegotiating) ->
+    undefined;
+
+handle_next_protocol(#server_hello{next_protocol_negotiation = Protocols},
+    NextProtocolSelector, Renegotiating) ->
+
+    case next_protocol_extension_allowed(NextProtocolSelector, Renegotiating) of
+        true ->
+            select_next_protocol(decode_next_protocols(Protocols), NextProtocolSelector);
+        false ->
+            ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE) % unexpected next protocol extension
+    end.
+
+select_next_protocol({error, _Reason}, _NextProtocolSelector) ->
+    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE);
+select_next_protocol(Protocols, NextProtocolSelector) ->
+    case NextProtocolSelector(Protocols) of
+	?NO_PROTOCOL ->
+	    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE);
+	Protocol when is_binary(Protocol)  ->
+	    Protocol
+    end.
+
+default_ecc_extensions(Version) ->
+    CryptoSupport = proplists:get_value(public_keys, crypto:supports()),
+    case proplists:get_bool(ecdh, CryptoSupport) of
+	true ->
+	    EcPointFormats = #ec_point_formats{ec_point_format_list = [?ECPOINT_UNCOMPRESSED]},
+	    EllipticCurves = #elliptic_curves{elliptic_curve_list = ssl_tls1:ecc_curves(Version)},
+	    {EcPointFormats, EllipticCurves};
+	_ ->
+	    {undefined, undefined}
+    end.
+
+handle_ecc_extensions(Version, EcPointFormats0, EllipticCurves0) ->
+    CryptoSupport = proplists:get_value(public_keys, crypto:supports()),
+    case proplists:get_bool(ecdh, CryptoSupport) of
+	true ->
+	    EcPointFormats1 = handle_ecc_point_fmt_extension(EcPointFormats0),
+	    EllipticCurves1 = handle_ecc_curves_extension(Version, EllipticCurves0),
+	    {EcPointFormats1, EllipticCurves1};
+	_ ->
+	    {undefined, undefined}
+    end.
+
+handle_ecc_point_fmt_extension(undefined) ->
+    undefined;
+handle_ecc_point_fmt_extension(_) ->
+    #ec_point_formats{ec_point_format_list = [?ECPOINT_UNCOMPRESSED]}.
+
+handle_ecc_curves_extension(Version, undefined) ->
+    undefined;
+handle_ecc_curves_extension(Version, _) ->
+    #elliptic_curves{elliptic_curve_list = ssl_tls1:ecc_curves(Version)}.
+
+handle_renegotiation_info(_, #renegotiation_info{renegotiated_connection = ?byte(0)}, 
+			  ConnectionStates, false, _, _) ->
+    {ok, tls_record:set_renegotiation_flag(true, ConnectionStates)};
+
+handle_renegotiation_info(server, undefined, ConnectionStates, _, _, CipherSuites) -> 
+    case is_member(?TLS_EMPTY_RENEGOTIATION_INFO_SCSV, CipherSuites) of
+	true ->
+	    {ok, tls_record:set_renegotiation_flag(true, ConnectionStates)};
+	false ->
+	    {ok, tls_record:set_renegotiation_flag(false, ConnectionStates)}
+    end;
+
+handle_renegotiation_info(_, undefined, ConnectionStates, false, _, _) ->
+    {ok, tls_record:set_renegotiation_flag(false, ConnectionStates)};
+
+handle_renegotiation_info(client, #renegotiation_info{renegotiated_connection = ClientServerVerify}, 
+			  ConnectionStates, true, _, _) ->
+    CS = tls_record:current_connection_state(ConnectionStates, read),
+    CData = CS#connection_state.client_verify_data,
+    SData = CS#connection_state.server_verify_data,    
+    case <<CData/binary, SData/binary>> == ClientServerVerify of
+	true ->
+	    {ok, ConnectionStates};
+	false ->
+	    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE)
+    end;
+handle_renegotiation_info(server, #renegotiation_info{renegotiated_connection = ClientVerify}, 
+			  ConnectionStates, true, _, CipherSuites) ->
+    
+      case is_member(?TLS_EMPTY_RENEGOTIATION_INFO_SCSV, CipherSuites) of
+	  true ->
+	      ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE);
+	  false ->	
+	      CS = tls_record:current_connection_state(ConnectionStates, read),
+	      Data = CS#connection_state.client_verify_data,
+	      case Data == ClientVerify of
+		  true ->
+		      {ok, ConnectionStates};
+		  false ->
+		      ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE)
+	      end
+      end;
+
+handle_renegotiation_info(client, undefined, ConnectionStates, true, SecureRenegotation, _) ->
+    handle_renegotiation_info(ConnectionStates, SecureRenegotation);
+
+handle_renegotiation_info(server, undefined, ConnectionStates, true, SecureRenegotation, CipherSuites) ->
+     case is_member(?TLS_EMPTY_RENEGOTIATION_INFO_SCSV, CipherSuites) of
+	  true ->
+	     ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE);
+	 false ->
+	     handle_renegotiation_info(ConnectionStates, SecureRenegotation)
+     end.
+
+handle_renegotiation_info(ConnectionStates, SecureRenegotation) ->
+    CS = tls_record:current_connection_state(ConnectionStates, read),
+    case {SecureRenegotation, CS#connection_state.secure_renegotiation} of
+	{_, true} ->
+	    ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE);
+	{true, false} ->
+	    ?ALERT_REC(?FATAL, ?NO_RENEGOTIATION);
+	{false, false} ->
+	    {ok, ConnectionStates}
+    end.
+
+%% Update pending connection states with parameters exchanged via 
+%% hello messages
+%% NOTE : Role is the role of the receiver of the hello message
+%%        currently being processed.
+hello_pending_connection_states(Role, Version, CipherSuite, Random, Compression,
+				 ConnectionStates) ->    
+    ReadState =  
+	tls_record:pending_connection_state(ConnectionStates, read),
+    WriteState = 
+	tls_record:pending_connection_state(ConnectionStates, write),
+    
+    NewReadSecParams = 
+	hello_security_parameters(Role, Version, ReadState, CipherSuite,
+			    Random, Compression),
+    
+    NewWriteSecParams =
+	hello_security_parameters(Role, Version, WriteState, CipherSuite,
+			    Random, Compression),
+ 
+    tls_record:update_security_params(NewReadSecParams,
+				    NewWriteSecParams,
+				    ConnectionStates).
+
+hello_security_parameters(client, Version, ConnectionState, CipherSuite, Random,
+			  Compression) ->   
+    SecParams = ConnectionState#connection_state.security_parameters,
+    NewSecParams = ssl_cipher:security_parameters(Version, CipherSuite, SecParams),
+    NewSecParams#security_parameters{
+      server_random = Random,
+      compression_algorithm = Compression
+     };
+
+hello_security_parameters(server, Version, ConnectionState, CipherSuite, Random,
+			  Compression) ->
+    SecParams = ConnectionState#connection_state.security_parameters,
+    NewSecParams = ssl_cipher:security_parameters(Version, CipherSuite, SecParams),
+    NewSecParams#security_parameters{
+      client_random = Random,
+      compression_algorithm = Compression
+     }.
+
+select_version(ClientVersion, Versions) ->   
+    ServerVersion = tls_record:highest_protocol_version(Versions),
+    tls_record:lowest_protocol_version(ClientVersion, ServerVersion).
+
+select_cipher_suite([], _) ->
+   no_suite;
+select_cipher_suite([Suite | ClientSuites], SupportedSuites) ->
+    case is_member(Suite, SupportedSuites) of
+	true ->
+	    Suite;
+        false ->
+	    select_cipher_suite(ClientSuites, SupportedSuites)
+    end.
+
+is_member(Suite, SupportedSuites) ->
+    lists:member(Suite, SupportedSuites).
+
+select_compression(_CompressionMetodes) ->
+    ?NULL.
+
+master_secret(Version, MasterSecret, #security_parameters{
+			 client_random = ClientRandom,
+			 server_random = ServerRandom,
+			 hash_size = HashSize,
+			 prf_algorithm = PrfAlgo,
+			 key_material_length = KML,
+			 expanded_key_material_length = EKML,
+			 iv_size = IVS},
+	      ConnectionStates, Role) ->
+    {ClientWriteMacSecret, ServerWriteMacSecret, ClientWriteKey,
+     ServerWriteKey, ClientIV, ServerIV} =
+	setup_keys(Version, PrfAlgo, MasterSecret, ServerRandom,
+		   ClientRandom, HashSize, KML, EKML, IVS),
+
+    ConnStates1 = tls_record:set_master_secret(MasterSecret, ConnectionStates),
+    ConnStates2 =
+	tls_record:set_mac_secret(ClientWriteMacSecret, ServerWriteMacSecret,
+				  Role, ConnStates1),
+
+    ClientCipherState = #cipher_state{iv = ClientIV, key = ClientWriteKey},
+    ServerCipherState = #cipher_state{iv = ServerIV, key = ServerWriteKey}, 
+    {MasterSecret, 
+     tls_record:set_pending_cipher_state(ConnStates2, ClientCipherState, 
+					 ServerCipherState, Role)}.
+
+
+dec_hs(_, ?NEXT_PROTOCOL, <<?BYTE(SelectedProtocolLength), SelectedProtocol:SelectedProtocolLength/binary,
+                         ?BYTE(PaddingLength), _Padding:PaddingLength/binary>>) ->
+	#next_protocol{selected_protocol = SelectedProtocol};
+
+dec_hs(_, ?HELLO_REQUEST, <<>>) ->
+    #hello_request{};
+
+%% Client hello v2.
+%% The server must be able to receive such messages, from clients that
+%% are willing to use ssl v3 or higher, but have ssl v2 compatibility.
+dec_hs(_Version, ?CLIENT_HELLO, <<?BYTE(Major), ?BYTE(Minor),
+				  ?UINT16(CSLength), ?UINT16(0),
+				  ?UINT16(CDLength),
+				  CipherSuites:CSLength/binary,
+				  ChallengeData:CDLength/binary>>) ->
+    #client_hello{client_version = {Major, Minor},
+		  random = ssl_ssl2:client_random(ChallengeData, CDLength),
+		  session_id = 0,
+		  cipher_suites = from_3bytes(CipherSuites),
+		  compression_methods = [?NULL],
+		  renegotiation_info = undefined
+		 };
+dec_hs(_Version, ?CLIENT_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+		       ?BYTE(SID_length), Session_ID:SID_length/binary,
+		       ?UINT16(Cs_length), CipherSuites:Cs_length/binary,
+		       ?BYTE(Cm_length), Comp_methods:Cm_length/binary,
+		       Extensions/binary>>) ->
+
+    DecodedExtensions = dec_hello_extensions(Extensions),
+    RenegotiationInfo = proplists:get_value(renegotiation_info, DecodedExtensions, undefined),
+    SRP = proplists:get_value(srp, DecodedExtensions, undefined),
+    HashSigns = proplists:get_value(hash_signs, DecodedExtensions, undefined),
+    EllipticCurves = proplists:get_value(elliptic_curves, DecodedExtensions,
+					 undefined),
+    NextProtocolNegotiation = proplists:get_value(next_protocol_negotiation, DecodedExtensions, undefined),
+
+    #client_hello{
+       client_version = {Major,Minor},
+       random = Random,
+       session_id = Session_ID,
+       cipher_suites = from_2bytes(CipherSuites),
+       compression_methods = Comp_methods,
+       renegotiation_info = RenegotiationInfo,
+	srp = SRP,
+       hash_signs = HashSigns,
+       elliptic_curves = EllipticCurves,
+       next_protocol_negotiation = NextProtocolNegotiation
+      };
+
+dec_hs(_Version, ?SERVER_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+		       ?BYTE(SID_length), Session_ID:SID_length/binary,
+		       Cipher_suite:2/binary, ?BYTE(Comp_method)>>) ->
+    #server_hello{
+	server_version = {Major,Minor},
+	random = Random,
+	session_id = Session_ID,
+	cipher_suite = Cipher_suite,
+	compression_method = Comp_method,
+	renegotiation_info = undefined,
+	hash_signs = undefined,
+	elliptic_curves = undefined};
+
+dec_hs(_Version, ?SERVER_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+		       ?BYTE(SID_length), Session_ID:SID_length/binary,
+		       Cipher_suite:2/binary, ?BYTE(Comp_method),
+		       ?UINT16(ExtLen), Extensions:ExtLen/binary>>) ->
+    
+    HelloExtensions = dec_hello_extensions(Extensions, []),
+    RenegotiationInfo = proplists:get_value(renegotiation_info, HelloExtensions,
+					   undefined),
+    HashSigns = proplists:get_value(hash_signs, HelloExtensions,
+					   undefined),
+    EllipticCurves = proplists:get_value(elliptic_curves, HelloExtensions,
+					   undefined),
+    NextProtocolNegotiation = proplists:get_value(next_protocol_negotiation, HelloExtensions, undefined),
+
+    #server_hello{
+	server_version = {Major,Minor},
+	random = Random,
+	session_id = Session_ID,
+	cipher_suite = Cipher_suite,
+	compression_method = Comp_method,
+	renegotiation_info = RenegotiationInfo,
+	hash_signs = HashSigns,
+	elliptic_curves = EllipticCurves,
+       next_protocol_negotiation = NextProtocolNegotiation};
+dec_hs(_Version, ?CERTIFICATE, <<?UINT24(ACLen), ASN1Certs:ACLen/binary>>) ->
+    #certificate{asn1_certificates = certs_to_list(ASN1Certs)};
+dec_hs(_Version, ?SERVER_KEY_EXCHANGE, Keys) ->
+    #server_key_exchange{exchange_keys = Keys};
+dec_hs({Major, Minor}, ?CERTIFICATE_REQUEST,
+       <<?BYTE(CertTypesLen), CertTypes:CertTypesLen/binary,
+	?UINT16(HashSignsLen), HashSigns:HashSignsLen/binary,
+	?UINT16(CertAuthsLen), CertAuths:CertAuthsLen/binary>>)
+  when Major == 3, Minor >= 3 ->
+    HashSignAlgos = [{ssl_cipher:hash_algorithm(Hash), ssl_cipher:sign_algorithm(Sign)} ||
+			<<?BYTE(Hash), ?BYTE(Sign)>> <= HashSigns],
+    #certificate_request{certificate_types = CertTypes,
+			 hashsign_algorithms = #hash_sign_algos{hash_sign_algos = HashSignAlgos},
+			 certificate_authorities = CertAuths};
+dec_hs(_Version, ?CERTIFICATE_REQUEST,
+       <<?BYTE(CertTypesLen), CertTypes:CertTypesLen/binary,
+	?UINT16(CertAuthsLen), CertAuths:CertAuthsLen/binary>>) ->
+    #certificate_request{certificate_types = CertTypes,
+			 certificate_authorities = CertAuths};
+dec_hs(_Version, ?SERVER_HELLO_DONE, <<>>) ->
+    #server_hello_done{};
+dec_hs({Major, Minor}, ?CERTIFICATE_VERIFY,<<HashSign:2/binary, ?UINT16(SignLen), Signature:SignLen/binary>>)
+  when Major == 3, Minor >= 3 ->
+    #certificate_verify{hashsign_algorithm = hashsign_dec(HashSign), signature = Signature};
+dec_hs(_Version, ?CERTIFICATE_VERIFY,<<?UINT16(SignLen), Signature:SignLen/binary>>)->
+    #certificate_verify{signature = Signature};
+dec_hs(_Version, ?CLIENT_KEY_EXCHANGE, PKEPMS) ->
+    #client_key_exchange{exchange_keys = PKEPMS};
+dec_hs(_Version, ?FINISHED, VerifyData) ->
+    #finished{verify_data = VerifyData};
+dec_hs(_, _, _) ->
+    throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE)).
+
+dec_client_key(PKEPMS, ?KEY_EXCHANGE_RSA, {3, 0}) ->
+    #encrypted_premaster_secret{premaster_secret = PKEPMS};
+dec_client_key(<<?UINT16(_), PKEPMS/binary>>, ?KEY_EXCHANGE_RSA, _) ->
+    #encrypted_premaster_secret{premaster_secret = PKEPMS};
+dec_client_key(<<>>, ?KEY_EXCHANGE_DIFFIE_HELLMAN, _) ->
+    throw(?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE));
+dec_client_key(<<?UINT16(DH_YLen), DH_Y:DH_YLen/binary>>,
+	       ?KEY_EXCHANGE_DIFFIE_HELLMAN, _) ->
+    #client_diffie_hellman_public{dh_public = DH_Y};
+dec_client_key(<<>>, ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN, _) ->
+    throw(?ALERT_REC(?FATAL, ?UNSUPPORTED_CERTIFICATE));
+dec_client_key(<<?BYTE(DH_YLen), DH_Y:DH_YLen/binary>>,
+	       ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN, _) ->
+    #client_ec_diffie_hellman_public{dh_public = DH_Y};
+dec_client_key(<<?UINT16(Len), Id:Len/binary>>,
+	       ?KEY_EXCHANGE_PSK, _) ->
+    #client_psk_identity{identity = Id};
+dec_client_key(<<?UINT16(Len), Id:Len/binary,
+		 ?UINT16(DH_YLen), DH_Y:DH_YLen/binary>>,
+	       ?KEY_EXCHANGE_DHE_PSK, _) ->
+    #client_dhe_psk_identity{identity = Id, dh_public = DH_Y};
+dec_client_key(<<?UINT16(Len), Id:Len/binary, PKEPMS/binary>>,
+	       ?KEY_EXCHANGE_RSA_PSK, {3, 0}) ->
+    #client_rsa_psk_identity{identity = Id, exchange_keys = #encrypted_premaster_secret{premaster_secret = PKEPMS}};
+dec_client_key(<<?UINT16(Len), Id:Len/binary, ?UINT16(_), PKEPMS/binary>>,
+	       ?KEY_EXCHANGE_RSA_PSK, _) ->
+    #client_rsa_psk_identity{identity = Id, exchange_keys = #encrypted_premaster_secret{premaster_secret = PKEPMS}};
+dec_client_key(<<?UINT16(ALen), A:ALen/binary>>,
+	       ?KEY_EXCHANGE_SRP, _) ->
+    #client_srp_public{srp_a = A}.
+
+dec_ske_params(Len, Keys, Version) ->
+    <<Params:Len/bytes, Signature/binary>> = Keys,
+    dec_ske_signature(Params, Signature, Version).
+
+dec_ske_signature(Params, <<?BYTE(HashAlgo), ?BYTE(SignAlgo),
+			    ?UINT16(0)>>, {Major, Minor})
+  when Major == 3, Minor >= 3 ->
+    HashSign = {ssl_cipher:hash_algorithm(HashAlgo), ssl_cipher:sign_algorithm(SignAlgo)},
+    {Params, HashSign, <<>>};
+dec_ske_signature(Params, <<?BYTE(HashAlgo), ?BYTE(SignAlgo),
+			    ?UINT16(Len), Signature:Len/binary>>, {Major, Minor})
+  when Major == 3, Minor >= 3 ->
+    HashSign = {ssl_cipher:hash_algorithm(HashAlgo), ssl_cipher:sign_algorithm(SignAlgo)},
+    {Params, HashSign, Signature};
+dec_ske_signature(Params, <<>>, _) ->
+    {Params, {null, anon}, <<>>};
+dec_ske_signature(Params, <<?UINT16(0)>>, _) ->
+    {Params, {null, anon}, <<>>};
+dec_ske_signature(Params, <<?UINT16(Len), Signature:Len/binary>>, _) ->
+    {Params, undefined, Signature};
+dec_ske_signature(_, _, _) ->
+    throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE)).
+
+dec_server_key(<<?UINT16(PLen), P:PLen/binary,
+		 ?UINT16(GLen), G:GLen/binary,
+		 ?UINT16(YLen), Y:YLen/binary, _/binary>> = KeyStruct,
+	       ?KEY_EXCHANGE_DIFFIE_HELLMAN, Version) ->
+    Params = #server_dh_params{dh_p = P, dh_g = G, dh_y = Y},
+    {BinMsg, HashSign, Signature} = dec_ske_params(PLen + GLen + YLen + 6, KeyStruct, Version),
+    #server_key_params{params = Params,
+		       params_bin = BinMsg,
+		       hashsign = HashSign,
+		       signature = Signature};
+%% ECParameters with named_curve
+%% TODO: explicit curve
+dec_server_key(<<?BYTE(?NAMED_CURVE), ?UINT16(CurveID),
+		 ?BYTE(PointLen), ECPoint:PointLen/binary,
+		 _/binary>> = KeyStruct,
+	       ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN, Version) ->
+    Params = #server_ecdh_params{curve = {namedCurve, ssl_tls1:enum_to_oid(CurveID)},
+				 public = ECPoint},
+    {BinMsg, HashSign, Signature} = dec_ske_params(PointLen + 4, KeyStruct, Version),
+    #server_key_params{params = Params,
+		       params_bin = BinMsg,
+		       hashsign = HashSign,
+		       signature = Signature};
+dec_server_key(<<?UINT16(Len), PskIdentityHint:Len/binary>> = KeyStruct,
+	       KeyExchange, Version)
+  when KeyExchange == ?KEY_EXCHANGE_PSK; KeyExchange == ?KEY_EXCHANGE_RSA_PSK ->
+    Params = #server_psk_params{
+      hint = PskIdentityHint},
+    {BinMsg, HashSign, Signature} = dec_ske_params(Len + 2, KeyStruct, Version),
+    #server_key_params{params = Params,
+		       params_bin = BinMsg,
+		       hashsign = HashSign,
+		       signature = Signature};
+dec_server_key(<<?UINT16(Len), IdentityHint:Len/binary,
+		 ?UINT16(PLen), P:PLen/binary,
+		 ?UINT16(GLen), G:GLen/binary,
+		 ?UINT16(YLen), Y:YLen/binary, _/binary>> = KeyStruct,
+	       ?KEY_EXCHANGE_DHE_PSK, Version) ->
+    DHParams = #server_dh_params{dh_p = P, dh_g = G, dh_y = Y},
+    Params = #server_dhe_psk_params{
+      hint = IdentityHint,
+      dh_params = DHParams},
+    {BinMsg, HashSign, Signature} = dec_ske_params(Len + PLen + GLen + YLen + 8, KeyStruct, Version),
+    #server_key_params{params = Params,
+		       params_bin = BinMsg,
+		       hashsign = HashSign,
+		       signature = Signature};
+dec_server_key(<<?UINT16(NLen), N:NLen/binary,
+		 ?UINT16(GLen), G:GLen/binary,
+		 ?BYTE(SLen), S:SLen/binary,
+		 ?UINT16(BLen), B:BLen/binary, _/binary>> = KeyStruct,
+	       ?KEY_EXCHANGE_SRP, Version) ->
+    Params = #server_srp_params{srp_n = N, srp_g = G, srp_s = S, srp_b = B},
+    {BinMsg, HashSign, Signature} = dec_ske_params(NLen + GLen + SLen + BLen + 7, KeyStruct, Version),
+    #server_key_params{params = Params,
+		       params_bin = BinMsg,
+		       hashsign = HashSign,
+		       signature = Signature};
+dec_server_key(_, _, _) ->
+    throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE)).
+
+dec_hello_extensions(<<>>) ->
+    [];
+dec_hello_extensions(<<?UINT16(ExtLen), Extensions:ExtLen/binary>>) ->
+    dec_hello_extensions(Extensions, []);
+dec_hello_extensions(_) ->
+    [].
+
+dec_hello_extensions(<<>>, Acc) ->
+    Acc;
+dec_hello_extensions(<<?UINT16(?NEXTPROTONEG_EXT), ?UINT16(Len), ExtensionData:Len/binary, Rest/binary>>, Acc) ->
+    Prop = {next_protocol_negotiation, #next_protocol_negotiation{extension_data = ExtensionData}},
+    dec_hello_extensions(Rest, [Prop | Acc]);
+dec_hello_extensions(<<?UINT16(?RENEGOTIATION_EXT), ?UINT16(Len), Info:Len/binary, Rest/binary>>, Acc) ->
+    RenegotiateInfo = case Len of
+			  1 ->  % Initial handshake
+			      Info; % should be <<0>> will be matched in handle_renegotiation_info
+			  _ ->
+			      VerifyLen = Len - 1,
+			      <<?BYTE(VerifyLen), VerifyInfo/binary>> = Info,
+			      VerifyInfo
+		      end,	    
+    dec_hello_extensions(Rest, [{renegotiation_info, 
+			   #renegotiation_info{renegotiated_connection = RenegotiateInfo}} | Acc]);
+
+dec_hello_extensions(<<?UINT16(?SRP_EXT), ?UINT16(Len), ?BYTE(SRPLen), SRP:SRPLen/binary, Rest/binary>>, Acc)
+  when Len == SRPLen + 2 ->
+    dec_hello_extensions(Rest, [{srp,
+			   #srp{username = SRP}} | Acc]);
+
+dec_hello_extensions(<<?UINT16(?SIGNATURE_ALGORITHMS_EXT), ?UINT16(Len),
+		       ExtData:Len/binary, Rest/binary>>, Acc) ->
+    SignAlgoListLen = Len - 2,
+    <<?UINT16(SignAlgoListLen), SignAlgoList/binary>> = ExtData,
+    HashSignAlgos = [{ssl_cipher:hash_algorithm(Hash), ssl_cipher:sign_algorithm(Sign)} ||
+			<<?BYTE(Hash), ?BYTE(Sign)>> <= SignAlgoList],
+    dec_hello_extensions(Rest, [{hash_signs,
+				 #hash_sign_algos{hash_sign_algos = HashSignAlgos}} | Acc]);
+
+dec_hello_extensions(<<?UINT16(?ELLIPTIC_CURVES_EXT), ?UINT16(Len),
+		       ExtData:Len/binary, Rest/binary>>, Acc) ->
+    EllipticCurveListLen = Len - 2,
+    <<?UINT16(EllipticCurveListLen), EllipticCurveList/binary>> = ExtData,
+    EllipticCurves = [ssl_tls1:enum_to_oid(X) || <<X:16>> <= EllipticCurveList],
+    dec_hello_extensions(Rest, [{elliptic_curves,
+				 #elliptic_curves{elliptic_curve_list = EllipticCurves}} | Acc]);
+
+dec_hello_extensions(<<?UINT16(?EC_POINT_FORMATS_EXT), ?UINT16(Len),
+		       ExtData:Len/binary, Rest/binary>>, Acc) ->
+    ECPointFormatListLen = Len - 1,
+    <<?BYTE(ECPointFormatListLen), ECPointFormatList/binary>> = ExtData,
+    ECPointFormats = binary_to_list(ECPointFormatList),
+    dec_hello_extensions(Rest, [{ec_point_formats,
+				 #ec_point_formats{ec_point_format_list = ECPointFormats}} | Acc]);
+
+%% Ignore data following the ClientHello (i.e.,
+%% extensions) if not understood.
+
+dec_hello_extensions(<<?UINT16(_), ?UINT16(Len), _Unknown:Len/binary, Rest/binary>>, Acc) ->
+    dec_hello_extensions(Rest, Acc);
+%% This theoretically should not happen if the protocol is followed, but if it does it is ignored.
+dec_hello_extensions(_, Acc) ->
+    Acc.
+
+encrypted_premaster_secret(Secret, RSAPublicKey) -> 
+    try 
+	PreMasterSecret = public_key:encrypt_public(Secret, RSAPublicKey, 
+						    [{rsa_pad, 
+						      rsa_pkcs1_padding}]),
+	#encrypted_premaster_secret{premaster_secret = PreMasterSecret}
+    catch
+	_:_->
+	    throw(?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE))
+    end.
+
+%% encode/decode stream of certificate data to/from list of certificate data 
+certs_to_list(ASN1Certs) ->
+    certs_to_list(ASN1Certs, []).
+
+certs_to_list(<<?UINT24(CertLen), Cert:CertLen/binary, Rest/binary>>, Acc) ->
+    certs_to_list(Rest, [Cert | Acc]);
+certs_to_list(<<>>, Acc) ->
+    lists:reverse(Acc, []).
+
+certs_from_list(ACList) ->
+    list_to_binary([begin
+			CertLen = byte_size(Cert),
+                        <<?UINT24(CertLen), Cert/binary>>
+		    end || Cert <- ACList]).
+
+enc_hs(#next_protocol{selected_protocol = SelectedProtocol}, _Version) ->
+    PaddingLength = 32 - ((byte_size(SelectedProtocol) + 2) rem 32),
+
+    {?NEXT_PROTOCOL, <<?BYTE((byte_size(SelectedProtocol))), SelectedProtocol/binary,
+                         ?BYTE(PaddingLength), 0:(PaddingLength * 8)>>};
+enc_hs(#hello_request{}, _Version) ->
+    {?HELLO_REQUEST, <<>>};
+enc_hs(#client_hello{client_version = {Major, Minor},
+		     random = Random,
+		     session_id = SessionID,
+		     cipher_suites = CipherSuites,
+		     compression_methods = CompMethods, 
+		     renegotiation_info = RenegotiationInfo,
+		     srp = SRP,
+		     hash_signs = HashSigns,
+		     ec_point_formats = EcPointFormats,
+		     elliptic_curves = EllipticCurves,
+		     next_protocol_negotiation = NextProtocolNegotiation}, _Version) ->
+    SIDLength = byte_size(SessionID),
+    BinCompMethods = list_to_binary(CompMethods),
+    CmLength = byte_size(BinCompMethods),
+    BinCipherSuites = list_to_binary(CipherSuites),
+    CsLength = byte_size(BinCipherSuites),
+    Extensions0 = hello_extensions(RenegotiationInfo, SRP, NextProtocolNegotiation)
+	++ ec_hello_extensions(lists:map(fun ssl_cipher:suite_definition/1, CipherSuites), EcPointFormats)
+	++ ec_hello_extensions(lists:map(fun ssl_cipher:suite_definition/1, CipherSuites), EllipticCurves),
+    Extensions1 = if
+		      Major == 3, Minor >=3 -> Extensions0 ++ hello_extensions(HashSigns);
+		      true -> Extensions0
+		  end,
+    ExtensionsBin = enc_hello_extensions(Extensions1),
+
+ {?CLIENT_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+		     ?BYTE(SIDLength), SessionID/binary,
+		     ?UINT16(CsLength), BinCipherSuites/binary,
+		     ?BYTE(CmLength), BinCompMethods/binary, ExtensionsBin/binary>>};
+
+enc_hs(#server_hello{server_version = {Major, Minor},
+		     random = Random,
+		     session_id = Session_ID,
+		     cipher_suite = CipherSuite,
+		     compression_method = Comp_method,
+		     renegotiation_info = RenegotiationInfo,
+		     ec_point_formats = EcPointFormats,
+		     elliptic_curves = EllipticCurves,
+		     next_protocol_negotiation = NextProtocolNegotiation}, _Version) ->
+    SID_length = byte_size(Session_ID),
+    CipherSuites = [ssl_cipher:suite_definition(CipherSuite)],
+    Extensions  = hello_extensions(RenegotiationInfo, NextProtocolNegotiation)
+	++ ec_hello_extensions(CipherSuites, EcPointFormats)
+	++ ec_hello_extensions(CipherSuites, EllipticCurves),
+    ExtensionsBin = enc_hello_extensions(Extensions),
+    {?SERVER_HELLO, <<?BYTE(Major), ?BYTE(Minor), Random:32/binary,
+		     ?BYTE(SID_length), Session_ID/binary,
+                     CipherSuite/binary, ?BYTE(Comp_method), ExtensionsBin/binary>>};
+enc_hs(#certificate{asn1_certificates = ASN1CertList}, _Version) ->
+    ASN1Certs = certs_from_list(ASN1CertList),
+    ACLen = erlang:iolist_size(ASN1Certs),
+    {?CERTIFICATE, <<?UINT24(ACLen), ASN1Certs:ACLen/binary>>};
+enc_hs(#server_key_exchange{exchange_keys = Keys}, _Version) ->
+    {?SERVER_KEY_EXCHANGE, Keys};
+enc_hs(#server_key_params{params_bin = Keys, hashsign = HashSign,
+			  signature = Signature}, Version) ->
+    EncSign = enc_sign(HashSign, Signature, Version),
+    {?SERVER_KEY_EXCHANGE, <<Keys/binary, EncSign/binary>>};
+enc_hs(#certificate_request{certificate_types = CertTypes,
+			    hashsign_algorithms = #hash_sign_algos{hash_sign_algos = HashSignAlgos},
+			    certificate_authorities = CertAuths},
+       {Major, Minor})
+  when Major == 3, Minor >= 3 ->
+    HashSigns= << <<(ssl_cipher:hash_algorithm(Hash)):8, (ssl_cipher:sign_algorithm(Sign)):8>> ||
+		   {Hash, Sign} <- HashSignAlgos >>,
+    CertTypesLen = byte_size(CertTypes),
+    HashSignsLen = byte_size(HashSigns),
+    CertAuthsLen = byte_size(CertAuths),
+    {?CERTIFICATE_REQUEST,
+       <<?BYTE(CertTypesLen), CertTypes/binary,
+	?UINT16(HashSignsLen), HashSigns/binary,
+	?UINT16(CertAuthsLen), CertAuths/binary>>
+    };
+enc_hs(#certificate_request{certificate_types = CertTypes,
+			    certificate_authorities = CertAuths}, 
+       _Version) ->
+    CertTypesLen = byte_size(CertTypes),
+    CertAuthsLen = byte_size(CertAuths),
+    {?CERTIFICATE_REQUEST,
+       <<?BYTE(CertTypesLen), CertTypes/binary,
+	?UINT16(CertAuthsLen), CertAuths/binary>>
+    };
+enc_hs(#server_hello_done{}, _Version) ->
+    {?SERVER_HELLO_DONE, <<>>};
+enc_hs(#client_key_exchange{exchange_keys = ExchangeKeys}, Version) ->
+    {?CLIENT_KEY_EXCHANGE, enc_cke(ExchangeKeys, Version)};
+enc_hs(#certificate_verify{signature = BinSig, hashsign_algorithm = HashSign}, Version) ->
+    EncSig = enc_sign(HashSign, BinSig, Version),
+    {?CERTIFICATE_VERIFY, EncSig};
+enc_hs(#finished{verify_data = VerifyData}, _Version) ->
+    {?FINISHED, VerifyData}.
+
+enc_cke(#encrypted_premaster_secret{premaster_secret = PKEPMS},{3, 0}) ->
+    PKEPMS;
+enc_cke(#encrypted_premaster_secret{premaster_secret = PKEPMS}, _) ->
+    PKEPMSLen = byte_size(PKEPMS),
+    <<?UINT16(PKEPMSLen), PKEPMS/binary>>;
+enc_cke(#client_diffie_hellman_public{dh_public = DHPublic}, _) ->
+    Len = byte_size(DHPublic),
+    <<?UINT16(Len), DHPublic/binary>>;
+enc_cke(#client_ec_diffie_hellman_public{dh_public = DHPublic}, _) ->
+    Len = byte_size(DHPublic),
+    <<?BYTE(Len), DHPublic/binary>>;
+enc_cke(#client_psk_identity{identity = undefined}, _) ->
+    Id = <<"psk_identity">>,
+    Len = byte_size(Id),
+    <<?UINT16(Len), Id/binary>>;
+enc_cke(#client_psk_identity{identity = Id}, _) ->
+    Len = byte_size(Id),
+    <<?UINT16(Len), Id/binary>>;
+enc_cke(Identity = #client_dhe_psk_identity{identity = undefined}, Version) ->
+    enc_cke(Identity#client_dhe_psk_identity{identity = <<"psk_identity">>}, Version);
+enc_cke(#client_dhe_psk_identity{identity = Id, dh_public = DHPublic}, _) ->
+    Len = byte_size(Id),
+    DHLen = byte_size(DHPublic),
+    <<?UINT16(Len), Id/binary, ?UINT16(DHLen), DHPublic/binary>>;
+enc_cke(Identity = #client_rsa_psk_identity{identity = undefined}, Version) ->
+    enc_cke(Identity#client_rsa_psk_identity{identity = <<"psk_identity">>}, Version);
+enc_cke(#client_rsa_psk_identity{identity = Id, exchange_keys = ExchangeKeys}, Version) ->
+    EncPMS = enc_cke(ExchangeKeys, Version),
+    Len = byte_size(Id),
+    <<?UINT16(Len), Id/binary, EncPMS/binary>>;
+enc_cke(#client_srp_public{srp_a = A}, _) ->
+    Len = byte_size(A),
+    <<?UINT16(Len), A/binary>>.
+
+enc_server_key(#server_dh_params{dh_p = P, dh_g = G, dh_y = Y}) ->
+    PLen = byte_size(P),
+    GLen = byte_size(G),
+    YLen = byte_size(Y),
+    <<?UINT16(PLen), P/binary, ?UINT16(GLen), G/binary, ?UINT16(YLen), Y/binary>>;
+enc_server_key(#server_ecdh_params{curve = {namedCurve, ECCurve}, public = ECPubKey}) ->
+    %%TODO: support arbitrary keys
+    KLen = size(ECPubKey),
+    <<?BYTE(?NAMED_CURVE_TYPE), ?UINT16((ssl_tls1:oid_to_enum(ECCurve))),
+      ?BYTE(KLen), ECPubKey/binary>>;
+enc_server_key(#server_psk_params{hint = PskIdentityHint}) ->
+    Len = byte_size(PskIdentityHint),
+    <<?UINT16(Len), PskIdentityHint/binary>>;
+enc_server_key(Params = #server_dhe_psk_params{hint = undefined}) ->
+    enc_server_key(Params#server_dhe_psk_params{hint = <<>>});
+enc_server_key(#server_dhe_psk_params{
+		  hint = PskIdentityHint,
+		  dh_params = #server_dh_params{dh_p = P, dh_g = G, dh_y = Y}}) ->
+    Len = byte_size(PskIdentityHint),
+    PLen = byte_size(P),
+    GLen = byte_size(G),
+    YLen = byte_size(Y),
+    <<?UINT16(Len), PskIdentityHint/binary,
+      ?UINT16(PLen), P/binary, ?UINT16(GLen), G/binary, ?UINT16(YLen), Y/binary>>;
+enc_server_key(#server_srp_params{srp_n = N, srp_g = G,	srp_s = S, srp_b = B}) ->
+    NLen = byte_size(N),
+    GLen = byte_size(G),
+    SLen = byte_size(S),
+    BLen = byte_size(B),
+    <<?UINT16(NLen), N/binary, ?UINT16(GLen), G/binary,
+      ?BYTE(SLen), S/binary, ?UINT16(BLen), B/binary>>.
+
+enc_sign({_, anon}, _Sign, _Version) ->
+    <<>>;
+enc_sign({HashAlg, SignAlg}, Signature, _Version = {Major, Minor})
+  when Major == 3, Minor >= 3->
+	SignLen = byte_size(Signature),
+	HashSign = hashsign_enc(HashAlg, SignAlg),
+	<<HashSign/binary, ?UINT16(SignLen), Signature/binary>>;
+enc_sign(_HashSign, Sign, _Version) ->
+	SignLen = byte_size(Sign),
+	<<?UINT16(SignLen), Sign/binary>>.
+
+
+ec_hello_extensions(CipherSuites, #elliptic_curves{} = Info) ->
+    case advertises_ec_ciphers(CipherSuites) of
+	true ->
+	    [Info];
+	false ->
+	    []
+    end;
+ec_hello_extensions(CipherSuites, #ec_point_formats{} = Info) ->
+    case advertises_ec_ciphers(CipherSuites) of
+	true ->
+	    [Info];
+	false ->
+	    []
+    end;
+ec_hello_extensions(_, undefined) ->
+    [].
+
+hello_extensions(RenegotiationInfo, NextProtocolNegotiation) ->
+    hello_extensions(RenegotiationInfo) ++ next_protocol_extension(NextProtocolNegotiation).
+
+hello_extensions(RenegotiationInfo, SRP, NextProtocolNegotiation) ->
+    hello_extensions(RenegotiationInfo)
+	++ hello_extensions(SRP)
+	++ next_protocol_extension(NextProtocolNegotiation).
+
+advertises_ec_ciphers([]) ->
+    false;
+advertises_ec_ciphers([{ecdh_ecdsa, _,_,_} | _]) ->
+    true;
+advertises_ec_ciphers([{ecdhe_ecdsa, _,_,_} | _]) ->
+    true;
+advertises_ec_ciphers([{ecdh_rsa, _,_,_} | _]) ->
+    true;
+advertises_ec_ciphers([{ecdhe_rsa, _,_,_} | _]) ->
+    true;
+advertises_ec_ciphers([{ecdh_anon, _,_,_} | _]) ->
+    true;
+advertises_ec_ciphers([_| Rest]) ->
+    advertises_ec_ciphers(Rest).
+
+%% Renegotiation info
+hello_extensions(#renegotiation_info{renegotiated_connection = undefined}) ->
+    [];
+hello_extensions(#renegotiation_info{} = Info) ->
+    [Info];
+hello_extensions(#srp{} = Info) ->
+    [Info];
+hello_extensions(#hash_sign_algos{} = Info) ->
+    [Info];
+hello_extensions(undefined) ->
+    [].
+
+next_protocol_extension(undefined) ->
+    [];
+next_protocol_extension(#next_protocol_negotiation{} = Info) ->
+    [Info].
+
+enc_hello_extensions(Extensions) ->
+    enc_hello_extensions(Extensions, <<>>).
+enc_hello_extensions([], <<>>) ->
+    <<>>;
+enc_hello_extensions([], Acc) ->
+    Size = byte_size(Acc),
+    <<?UINT16(Size), Acc/binary>>;
+
+enc_hello_extensions([#next_protocol_negotiation{extension_data = ExtensionData} | Rest], Acc) ->
+    Len = byte_size(ExtensionData),
+    enc_hello_extensions(Rest, <<?UINT16(?NEXTPROTONEG_EXT), ?UINT16(Len), ExtensionData/binary, Acc/binary>>);
+enc_hello_extensions([#renegotiation_info{renegotiated_connection = ?byte(0) = Info} | Rest], Acc) ->
+    Len = byte_size(Info),
+    enc_hello_extensions(Rest, <<?UINT16(?RENEGOTIATION_EXT), ?UINT16(Len), Info/binary, Acc/binary>>);
+
+enc_hello_extensions([#renegotiation_info{renegotiated_connection = Info} | Rest], Acc) ->
+    InfoLen = byte_size(Info),
+    Len = InfoLen +1,
+    enc_hello_extensions(Rest, <<?UINT16(?RENEGOTIATION_EXT), ?UINT16(Len), ?BYTE(InfoLen), Info/binary, Acc/binary>>);
+enc_hello_extensions([#elliptic_curves{elliptic_curve_list = EllipticCurves} | Rest], Acc) ->
+    EllipticCurveList = << <<(ssl_tls1:oid_to_enum(X)):16>> || X <- EllipticCurves>>,
+    ListLen = byte_size(EllipticCurveList),
+    Len = ListLen + 2,
+    enc_hello_extensions(Rest, <<?UINT16(?ELLIPTIC_CURVES_EXT),
+				 ?UINT16(Len), ?UINT16(ListLen), EllipticCurveList/binary, Acc/binary>>);
+enc_hello_extensions([#ec_point_formats{ec_point_format_list = ECPointFormats} | Rest], Acc) ->
+    ECPointFormatList = list_to_binary(ECPointFormats),
+    ListLen = byte_size(ECPointFormatList),
+    Len = ListLen + 1,
+    enc_hello_extensions(Rest, <<?UINT16(?EC_POINT_FORMATS_EXT),
+				 ?UINT16(Len), ?BYTE(ListLen), ECPointFormatList/binary, Acc/binary>>);
+enc_hello_extensions([#srp{username = UserName} | Rest], Acc) ->
+    SRPLen = byte_size(UserName),
+    Len = SRPLen + 2,
+    enc_hello_extensions(Rest, <<?UINT16(?SRP_EXT), ?UINT16(Len), ?BYTE(SRPLen), UserName/binary, Acc/binary>>);
+enc_hello_extensions([#hash_sign_algos{hash_sign_algos = HashSignAlgos} | Rest], Acc) ->
+    SignAlgoList = << <<(ssl_cipher:hash_algorithm(Hash)):8, (ssl_cipher:sign_algorithm(Sign)):8>> ||
+		       {Hash, Sign} <- HashSignAlgos >>,
+    ListLen = byte_size(SignAlgoList),
+    Len = ListLen + 2,
+    enc_hello_extensions(Rest, <<?UINT16(?SIGNATURE_ALGORITHMS_EXT), 
+				 ?UINT16(Len), ?UINT16(ListLen), SignAlgoList/binary, Acc/binary>>).
+
+encode_client_protocol_negotiation(undefined, _) ->
+    undefined;
+encode_client_protocol_negotiation(_, false) ->
+	#next_protocol_negotiation{extension_data = <<>>};
+encode_client_protocol_negotiation(_, _) ->
+	undefined.
+
+from_3bytes(Bin3) ->
+    from_3bytes(Bin3, []).
+
+from_3bytes(<<>>, Acc) ->
+    lists:reverse(Acc);
+from_3bytes(<<?UINT24(N), Rest/binary>>, Acc) ->
+    from_3bytes(Rest, [?uint16(N) | Acc]).
+
+from_2bytes(Bin2) ->
+    from_2bytes(Bin2, []).
+
+from_2bytes(<<>>, Acc) ->
+    lists:reverse(Acc);
+from_2bytes(<<?UINT16(N), Rest/binary>>, Acc) ->
+    from_2bytes(Rest, [?uint16(N) | Acc]).
+
+certificate_types({KeyExchange, _, _, _})  
+  when KeyExchange == rsa;
+       KeyExchange == dhe_dss;
+       KeyExchange == dhe_rsa;
+       KeyExchange == ecdhe_rsa ->
+    <<?BYTE(?RSA_SIGN), ?BYTE(?DSS_SIGN)>>;
+
+certificate_types({KeyExchange, _, _, _})
+  when KeyExchange == dh_ecdsa;
+       KeyExchange == dhe_ecdsa ->
+    <<?BYTE(?ECDSA_SIGN)>>;
+
+certificate_types(_) ->
+    <<?BYTE(?RSA_SIGN)>>.
+
+hashsign_dec(<<?BYTE(HashAlgo), ?BYTE(SignAlgo)>>) ->
+    {ssl_cipher:hash_algorithm(HashAlgo), ssl_cipher:sign_algorithm(SignAlgo)}.
+
+hashsign_enc(HashAlgo, SignAlgo) ->
+    Hash = ssl_cipher:hash_algorithm(HashAlgo),
+    Sign = ssl_cipher:sign_algorithm(SignAlgo),
+    <<?BYTE(Hash), ?BYTE(Sign)>>.
+
+certificate_authorities(CertDbHandle, CertDbRef) ->
+    Authorities = certificate_authorities_from_db(CertDbHandle, CertDbRef),
+    Enc = fun(#'OTPCertificate'{tbsCertificate=TBSCert}) ->
+		  OTPSubj = TBSCert#'OTPTBSCertificate'.subject,
+		  DNEncodedBin = public_key:pkix_encode('Name', OTPSubj, otp),
+		  DNEncodedLen = byte_size(DNEncodedBin),
+		  <<?UINT16(DNEncodedLen), DNEncodedBin/binary>>
+	  end,
+    list_to_binary([Enc(Cert) || {_, Cert} <- Authorities]).
+
+certificate_authorities_from_db(CertDbHandle, CertDbRef) ->
+    ConnectionCerts = fun({{Ref, _, _}, Cert}, Acc) when Ref  == CertDbRef ->
+			      [Cert | Acc];
+			 (_, Acc) ->
+			      Acc
+		      end,
+    ssl_pkix_db:foldl(ConnectionCerts, [], CertDbHandle).
+
+
+digitally_signed({3, Minor}, Hash, HashAlgo, Key) when Minor >= 3 ->
+    public_key:sign({digest, Hash}, HashAlgo, Key);
+digitally_signed(_Version, Hash, HashAlgo, #'DSAPrivateKey'{} = Key) ->
+    public_key:sign({digest, Hash}, HashAlgo, Key);
+digitally_signed(_Version, Hash, _HashAlgo, #'RSAPrivateKey'{} = Key) ->
+    public_key:encrypt_private(Hash, Key,
+			       [{rsa_pad, rsa_pkcs1_padding}]);
+digitally_signed(_Version, Hash, HashAlgo, Key) ->
+    public_key:sign({digest, Hash}, HashAlgo, Key).
+
+calc_master_secret({3,0}, _PrfAlgo, PremasterSecret, ClientRandom, ServerRandom) ->
+    ssl_ssl3:master_secret(PremasterSecret, ClientRandom, ServerRandom);
+
+calc_master_secret({3,_}, PrfAlgo, PremasterSecret, ClientRandom, ServerRandom) ->
+    ssl_tls1:master_secret(PrfAlgo, PremasterSecret, ClientRandom, ServerRandom).
+
+setup_keys({3,0}, _PrfAlgo, MasterSecret,
+	   ServerRandom, ClientRandom, HashSize, KML, EKML, IVS) ->
+    ssl_ssl3:setup_keys(MasterSecret, ServerRandom,
+			ClientRandom, HashSize, KML, EKML, IVS);
+
+setup_keys({3,N}, PrfAlgo, MasterSecret,
+	   ServerRandom, ClientRandom, HashSize, KML, _EKML, IVS) ->
+    ssl_tls1:setup_keys(N, PrfAlgo, MasterSecret, ServerRandom, ClientRandom, HashSize,
+			KML, IVS).
+
+calc_finished({3, 0}, Role, _PrfAlgo, MasterSecret, Handshake) ->
+    ssl_ssl3:finished(Role, MasterSecret, lists:reverse(Handshake));
+calc_finished({3, N}, Role, PrfAlgo, MasterSecret, Handshake) ->
+    ssl_tls1:finished(Role, N, PrfAlgo, MasterSecret, lists:reverse(Handshake)).
+
+calc_certificate_verify({3, 0}, HashAlgo, MasterSecret, Handshake) ->
+    ssl_ssl3:certificate_verify(HashAlgo, MasterSecret, lists:reverse(Handshake));
+calc_certificate_verify({3, N}, HashAlgo, _MasterSecret, Handshake) ->
+    ssl_tls1:certificate_verify(HashAlgo, N, lists:reverse(Handshake)).
+
+key_exchange_alg(rsa) ->
+    ?KEY_EXCHANGE_RSA;
+key_exchange_alg(Alg) when Alg == dhe_rsa; Alg == dhe_dss;
+			    Alg == dh_dss; Alg == dh_rsa; Alg == dh_anon ->
+    ?KEY_EXCHANGE_DIFFIE_HELLMAN;
+key_exchange_alg(Alg) when Alg == ecdhe_rsa; Alg == ecdh_rsa;
+			   Alg == ecdhe_ecdsa; Alg == ecdh_ecdsa;
+			   Alg == ecdh_anon ->
+    ?KEY_EXCHANGE_EC_DIFFIE_HELLMAN;
+key_exchange_alg(psk) ->
+    ?KEY_EXCHANGE_PSK;
+key_exchange_alg(dhe_psk) ->
+    ?KEY_EXCHANGE_DHE_PSK;
+key_exchange_alg(rsa_psk) ->
+    ?KEY_EXCHANGE_RSA_PSK;
+key_exchange_alg(Alg)
+  when Alg == srp_rsa; Alg == srp_dss; Alg == srp_anon ->
+    ?KEY_EXCHANGE_SRP;
+key_exchange_alg(_) ->
+    ?NULL.
+
+apply_user_fun(Fun, OtpCert, ExtensionOrError, UserState0, SslState) ->
+    case Fun(OtpCert, ExtensionOrError, UserState0) of
+	{valid, UserState} ->
+	    {valid, {SslState, UserState}};
+	{fail, _} = Fail ->
+	    Fail;
+	{unknown, UserState} ->
+	    {unknown, {SslState, UserState}}
+    end.
+
+-define(TLSEXT_SIGALG_RSA(MD), {MD, rsa}).
+-define(TLSEXT_SIGALG_DSA(MD), {MD, dsa}).
+-define(TLSEXT_SIGALG_ECDSA(MD), {MD, ecdsa}).
+
+-define(TLSEXT_SIGALG(MD), ?TLSEXT_SIGALG_ECDSA(MD), ?TLSEXT_SIGALG_RSA(MD)).
+
+default_hash_signs() ->
+    HashSigns = [?TLSEXT_SIGALG(sha512),
+		 ?TLSEXT_SIGALG(sha384),
+		 ?TLSEXT_SIGALG(sha256),
+		 ?TLSEXT_SIGALG(sha224),
+		 ?TLSEXT_SIGALG(sha),
+		 ?TLSEXT_SIGALG_DSA(sha),
+		 ?TLSEXT_SIGALG_RSA(md5)],
+    CryptoSupport = proplists:get_value(public_keys, crypto:supports()),
+    HasECC = proplists:get_bool(ecdsa, CryptoSupport),
+    #hash_sign_algos{hash_sign_algos =
+			 lists:filter(fun({_, ecdsa}) -> HasECC;
+					 (_) -> true end, HashSigns)}.
+
+handle_hello_extensions(#client_hello{random = Random,
+				      cipher_suites = CipherSuites,
+				      renegotiation_info = Info,
+				      srp = SRP,
+				      ec_point_formats = EcPointFormats0,
+				      elliptic_curves = EllipticCurves0} = Hello, Version,
+			#ssl_options{secure_renegotiate = SecureRenegotation} = Opts,
+			Session0, ConnectionStates0, Renegotiation) ->
+    Session = handle_srp_extension(SRP, Session0),
+    ConnectionStates = handle_renegotiation_extension(Version, Info, Random, Session, ConnectionStates0,
+						      Renegotiation, SecureRenegotation, CipherSuites),
+    ProtocolsToAdvertise = handle_next_protocol_extension(Hello, Renegotiation, Opts),
+    {EcPointFormats, EllipticCurves} = handle_ecc_extensions(Version, EcPointFormats0, EllipticCurves0),
+    %%TODO make extensions compund data structure
+    {Session, ConnectionStates, ProtocolsToAdvertise, EcPointFormats, EllipticCurves}.
+
+
+handle_renegotiation_extension(Version, Info, Random, #session{cipher_suite = CipherSuite,
+							       compression_method = Compression},
+			       ConnectionStates0, Renegotiation, SecureRenegotation, CipherSuites) ->
+    case handle_renegotiation_info(server, Info, ConnectionStates0,
+				   Renegotiation, SecureRenegotation,
+				   CipherSuites) of
+	{ok, ConnectionStates1} ->
+	    hello_pending_connection_states(server,
+					    Version,
+					    CipherSuite,
+					    Random,
+					    Compression,
+					    ConnectionStates1);
+	#alert{} = Alert ->
+	    throw(Alert)
+    end.
+
+handle_next_protocol_extension(Hello, Renegotiation, SslOpts)->
+    case handle_next_protocol_on_server(Hello, Renegotiation, SslOpts) of
+	#alert{} = Alert ->
+	    throw(Alert);
+	ProtocolsToAdvertise ->
+	    ProtocolsToAdvertise
+    end.
+
+handle_srp_extension(undefined, Session) ->
+    Session;
+handle_srp_extension(#srp{username = Username}, Session) ->
+    Session#session{srp_username = Username}.
+
+int_to_bin(I) ->
+    L = (length(integer_to_list(I, 16)) + 1) div 2,
+    <<I:(L*8)>>.