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-rw-r--r--lib/ssl/src/ssl_handshake.erl259
1 files changed, 167 insertions, 92 deletions
diff --git a/lib/ssl/src/ssl_handshake.erl b/lib/ssl/src/ssl_handshake.erl
index e9e140836b..43b0c42f8d 100644
--- a/lib/ssl/src/ssl_handshake.erl
+++ b/lib/ssl/src/ssl_handshake.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 2013-2015. All Rights Reserved.
+%% Copyright Ericsson AB 2013-2016. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
@@ -46,7 +46,7 @@
%% Handshake messages
-export([hello_request/0, server_hello/4, server_hello_done/0,
- certificate/4, certificate_request/4, key_exchange/3,
+ certificate/4, certificate_request/5, key_exchange/3,
finished/5, next_protocol/1]).
%% Handle handshake messages
@@ -64,8 +64,8 @@
]).
%% Cipher suites handling
--export([available_suites/2, cipher_suites/2,
- select_session/10, supported_ecc/1]).
+-export([available_suites/2, available_signature_algs/3, cipher_suites/2,
+ select_session/11, supported_ecc/1]).
%% Extensions handling
-export([client_hello_extensions/6,
@@ -74,8 +74,8 @@
]).
%% MISC
--export([select_version/3, prf/5, select_hashsign/3,
- select_hashsign_algs/2, select_hashsign_algs/3,
+-export([select_version/3, prf/6, select_hashsign/5,
+ select_hashsign_algs/3,
premaster_secret/2, premaster_secret/3, premaster_secret/4]).
%%====================================================================
@@ -120,7 +120,8 @@ server_hello(SessionId, Version, ConnectionStates, Extensions) ->
server_hello_done() ->
#server_hello_done{}.
-client_hello_extensions(Host, Version, CipherSuites, SslOpts, ConnectionStates, Renegotiation) ->
+client_hello_extensions(Host, Version, CipherSuites,
+ #ssl_options{signature_algs = SupportedHashSigns, versions = AllVersions} = SslOpts, ConnectionStates, Renegotiation) ->
{EcPointFormats, EllipticCurves} =
case advertises_ec_ciphers(lists:map(fun ssl_cipher:suite_definition/1, CipherSuites)) of
true ->
@@ -134,7 +135,7 @@ client_hello_extensions(Host, Version, CipherSuites, SslOpts, ConnectionStates,
renegotiation_info = renegotiation_info(tls_record, client,
ConnectionStates, Renegotiation),
srp = SRP,
- hash_signs = advertised_hash_signs(Version),
+ signature_algs = available_signature_algs(SupportedHashSigns, Version, AllVersions),
ec_point_formats = EcPointFormats,
elliptic_curves = EllipticCurves,
alpn = encode_alpn(SslOpts#ssl_options.alpn_advertised_protocols, Renegotiation),
@@ -203,14 +204,14 @@ client_certificate_verify(OwnCert, MasterSecret, Version,
end.
%%--------------------------------------------------------------------
--spec certificate_request(ssl_cipher:cipher_suite(), db_handle(), certdb_ref(), ssl_record:ssl_version()) ->
- #certificate_request{}.
+-spec certificate_request(ssl_cipher:cipher_suite(), db_handle(),
+ certdb_ref(), #hash_sign_algos{}, ssl_record:ssl_version()) ->
+ #certificate_request{}.
%%
%% Description: Creates a certificate_request message, called by the server.
%%--------------------------------------------------------------------
-certificate_request(CipherSuite, CertDbHandle, CertDbRef, Version) ->
+certificate_request(CipherSuite, CertDbHandle, CertDbRef, HashSigns, Version) ->
Types = certificate_types(ssl_cipher:suite_definition(CipherSuite), Version),
- HashSigns = advertised_hash_signs(Version),
Authorities = certificate_authorities(CertDbHandle, CertDbRef),
#certificate_request{
certificate_types = Types,
@@ -351,6 +352,9 @@ verify_server_key(#server_key_params{params_bin = EncParams,
%%
%% Description: Checks that the certificate_verify message is valid.
%%--------------------------------------------------------------------
+certificate_verify(_, _, _, undefined, _, _) ->
+ ?ALERT_REC(?FATAL, ?HANDSHAKE_FAILURE);
+
certificate_verify(Signature, PublicKeyInfo, Version,
HashSign = {HashAlgo, _}, MasterSecret, {_, Handshake}) ->
Hash = calc_certificate_verify(Version, HashAlgo, MasterSecret, Handshake),
@@ -379,10 +383,11 @@ verify_signature(_Version, Hash, _HashAlgo, Signature, {?rsaEncryption, PubKey,
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,
+verify_signature(_, Hash, {HashAlgo, _SignAlg}, Signature,
{?'id-ecPublicKey', PublicKey, PublicKeyParams}) ->
public_key:verify({digest, Hash}, HashAlgo, Signature, {PublicKey, PublicKeyParams}).
+
%%--------------------------------------------------------------------
-spec certify(#certificate{}, db_handle(), certdb_ref(), integer() | nolimit,
verify_peer | verify_none, {fun(), term}, fun(), term(), term(),
@@ -559,57 +564,58 @@ server_key_exchange_hash(md5sha, Value) ->
server_key_exchange_hash(Hash, Value) ->
crypto:hash(Hash, Value).
%%--------------------------------------------------------------------
--spec prf(ssl_record:ssl_version(), binary(), binary(), [binary()], non_neg_integer()) ->
+-spec prf(ssl_record:ssl_version(), non_neg_integer(), binary(), binary(), [binary()], non_neg_integer()) ->
{ok, binary()} | {error, undefined}.
%%
%% Description: use the TLS PRF to generate key material
%%--------------------------------------------------------------------
-prf({3,0}, _, _, _, _) ->
+prf({3,0}, _, _, _, _, _) ->
{error, undefined};
-prf({3,1}, Secret, Label, Seed, WantedLength) ->
- {ok, tls_v1:prf(?MD5SHA, Secret, Label, Seed, WantedLength)};
-prf({3,_N}, Secret, Label, Seed, WantedLength) ->
- {ok, tls_v1:prf(?SHA256, Secret, Label, Seed, WantedLength)}.
+prf({3,_N}, PRFAlgo, Secret, Label, Seed, WantedLength) ->
+ {ok, tls_v1:prf(PRFAlgo, Secret, Label, Seed, WantedLength)}.
%%--------------------------------------------------------------------
--spec select_hashsign(#hash_sign_algos{}| undefined, undefined | binary(), ssl_record:ssl_version()) ->
- {atom(), atom()} | undefined.
+-spec select_hashsign(#hash_sign_algos{} | undefined, undefined | binary(),
+ atom(), [atom()], ssl_record:ssl_version()) ->
+ {atom(), atom()} | undefined | #alert{}.
%%
-%% Description:
+%% Description: Handles signature_algorithms extension
%%--------------------------------------------------------------------
-select_hashsign(_, undefined, _Version) ->
+select_hashsign(_, undefined, _, _, _Version) ->
{null, anon};
%% The signature_algorithms extension was introduced with TLS 1.2. Ignore it if we have
%% negotiated a lower version.
-select_hashsign(#hash_sign_algos{hash_sign_algos = HashSigns}, Cert, {Major, Minor} = Version)
- when Major >= 3 andalso Minor >= 3 ->
- #'OTPCertificate'{tbsCertificate = TBSCert} =public_key:pkix_decode_cert(Cert, otp),
+select_hashsign(HashSigns, Cert, KeyExAlgo,
+ undefined, {Major, Minor} = Version) when Major >= 3 andalso Minor >= 3->
+ select_hashsign(HashSigns, Cert, KeyExAlgo, tls_v1:default_signature_algs(Version), Version);
+select_hashsign(#hash_sign_algos{hash_sign_algos = HashSigns}, Cert, KeyExAlgo, SupportedHashSigns,
+ {Major, Minor}) when Major >= 3 andalso Minor >= 3 ->
+ #'OTPCertificate'{tbsCertificate = TBSCert} = public_key:pkix_decode_cert(Cert, otp),
#'OTPSubjectPublicKeyInfo'{algorithm = {_,Algo, _}} = TBSCert#'OTPTBSCertificate'.subjectPublicKeyInfo,
- DefaultHashSign = {_, Sign} = select_hashsign_algs(undefined, Algo, Version),
- case lists:filter(fun({sha, dsa}) ->
+ Sign = cert_sign(Algo),
+ case lists:filter(fun({sha, dsa = S}) when S == Sign ->
true;
({_, dsa}) ->
false;
- ({Hash, S}) when S == Sign ->
- ssl_cipher:is_acceptable_hash(Hash,
- proplists:get_value(hashs, crypto:supports()));
+ ({_, _} = Algos) ->
+ is_acceptable_hash_sign(Algos, Sign, KeyExAlgo, SupportedHashSigns);
(_) ->
false
end, HashSigns) of
[] ->
- DefaultHashSign;
- [HashSign| _] ->
+ ?ALERT_REC(?FATAL, ?INSUFFICIENT_SECURITY);
+ [HashSign | _] ->
HashSign
end;
-select_hashsign(_, Cert, Version) ->
+select_hashsign(_, Cert, _, _, Version) ->
#'OTPCertificate'{tbsCertificate = TBSCert} = public_key:pkix_decode_cert(Cert, otp),
#'OTPSubjectPublicKeyInfo'{algorithm = {_,Algo, _}} = TBSCert#'OTPTBSCertificate'.subjectPublicKeyInfo,
select_hashsign_algs(undefined, Algo, Version).
%%--------------------------------------------------------------------
--spec select_hashsign_algs(#hash_sign_algos{}| undefined, oid(), ssl_record:ssl_version()) ->
+-spec select_hashsign_algs({atom(), atom()}| undefined, oid(), ssl_record:ssl_version()) ->
{atom(), atom()}.
%% Description: For TLS 1.2 hash function and signature algorithm pairs can be
@@ -642,24 +648,6 @@ select_hashsign_algs(undefined, ?rsaEncryption, _) ->
select_hashsign_algs(undefined, ?'id-dsa', _) ->
{sha, dsa}.
--spec select_hashsign_algs(atom(), ssl_record:ssl_version()) -> {atom(), atom()}.
-%% Wrap function to keep the knowledge of the default values in
-%% one place only
-select_hashsign_algs(Alg, Version) when (Alg == rsa orelse
- Alg == dhe_rsa orelse
- Alg == dh_rsa orelse
- Alg == ecdhe_rsa orelse
- Alg == ecdh_rsa orelse
- Alg == srp_rsa) ->
- select_hashsign_algs(undefined, ?rsaEncryption, Version);
-select_hashsign_algs(Alg, Version) when (Alg == dhe_dss orelse
- Alg == dh_dss orelse
- Alg == srp_dss) ->
- select_hashsign_algs(undefined, ?'id-dsa', Version);
-select_hashsign_algs(Alg, Version) when (Alg == ecdhe_ecdsa orelse
- Alg == ecdh_ecdsa) ->
- select_hashsign_algs(undefined, ?'id-ecPublicKey', Version).
-
%%--------------------------------------------------------------------
-spec master_secret(atom(), ssl_record:ssl_version(), #session{} | binary(), #connection_states{},
client | server) -> {binary(), #connection_states{}} | #alert{}.
@@ -1063,9 +1051,56 @@ available_suites(UserSuites, Version) ->
lists:member(Suite, ssl_cipher:all_suites(Version))
end, UserSuites).
-available_suites(ServerCert, UserSuites, Version, Curve) ->
+available_suites(ServerCert, UserSuites, Version, undefined, Curve) ->
ssl_cipher:filter(ServerCert, available_suites(UserSuites, Version))
- -- unavailable_ecc_suites(Curve).
+ -- unavailable_ecc_suites(Curve);
+available_suites(ServerCert, UserSuites, Version, HashSigns, Curve) ->
+ Suites = available_suites(ServerCert, UserSuites, Version, undefined, Curve),
+ filter_hashsigns(Suites, [ssl_cipher:suite_definition(Suite) || Suite <- Suites], HashSigns, []).
+filter_hashsigns([], [], _, Acc) ->
+ lists:reverse(Acc);
+filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns,
+ Acc) when KeyExchange == dhe_ecdsa;
+ KeyExchange == ecdhe_ecdsa ->
+ do_filter_hashsigns(ecdsa, Suite, Suites, Algos, HashSigns, Acc);
+
+filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns,
+ Acc) when KeyExchange == rsa;
+ KeyExchange == dhe_rsa;
+ KeyExchange == ecdhe_rsa;
+ KeyExchange == srp_rsa;
+ KeyExchange == rsa_psk ->
+ do_filter_hashsigns(rsa, Suite, Suites, Algos, HashSigns, Acc);
+filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when
+ KeyExchange == dhe_dss;
+ KeyExchange == srp_dss ->
+ do_filter_hashsigns(dsa, Suite, Suites, Algos, HashSigns, Acc);
+filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when
+ KeyExchange == dh_dss;
+ KeyExchange == dh_rsa;
+ KeyExchange == dh_ecdsa;
+ KeyExchange == ecdh_rsa;
+ KeyExchange == ecdh_ecdsa ->
+ %% Fixed DH certificates MAY be signed with any hash/signature
+ %% algorithm pair appearing in the hash_sign extension. The names
+ %% DH_DSS, DH_RSA, ECDH_ECDSA, and ECDH_RSA are historical.
+ filter_hashsigns(Suites, Algos, HashSigns, [Suite| Acc]);
+filter_hashsigns([Suite | Suites], [{KeyExchange,_,_,_} | Algos], HashSigns, Acc) when
+ KeyExchange == dh_anon;
+ KeyExchange == ecdh_anon;
+ KeyExchange == srp_anon;
+ KeyExchange == psk;
+ KeyExchange == dhe_psk ->
+ %% In this case hashsigns is not used as the kexchange is anonaymous
+ filter_hashsigns(Suites, Algos, HashSigns, [Suite| Acc]).
+
+do_filter_hashsigns(SignAlgo, Suite, Suites, Algos, HashSigns, Acc) ->
+ case lists:keymember(SignAlgo, 2, HashSigns) of
+ true ->
+ filter_hashsigns(Suites, Algos, HashSigns, [Suite| Acc]);
+ false ->
+ filter_hashsigns(Suites, Algos, HashSigns, Acc)
+ end.
unavailable_ecc_suites(no_curve) ->
ssl_cipher:ec_keyed_suites();
@@ -1077,17 +1112,17 @@ cipher_suites(Suites, false) ->
cipher_suites(Suites, true) ->
Suites.
-select_session(SuggestedSessionId, CipherSuites, Compressions, Port, #session{ecc = ECCCurve} =
+select_session(SuggestedSessionId, CipherSuites, HashSigns, Compressions, Port, #session{ecc = ECCCurve} =
Session, Version,
- #ssl_options{ciphers = UserSuites, honor_cipher_order = HCO} = SslOpts,
+ #ssl_options{ciphers = UserSuites, honor_cipher_order = HonorCipherOrder} = SslOpts,
Cache, CacheCb, Cert) ->
{SessionId, Resumed} = ssl_session:server_id(Port, SuggestedSessionId,
SslOpts, Cert,
Cache, CacheCb),
case Resumed of
undefined ->
- Suites = available_suites(Cert, UserSuites, Version, ECCCurve),
- CipherSuite = select_cipher_suite(CipherSuites, Suites, HCO),
+ Suites = available_suites(Cert, UserSuites, Version, HashSigns, ECCCurve),
+ CipherSuite = select_cipher_suite(CipherSuites, Suites, HonorCipherOrder),
Compression = select_compression(Compressions),
{new, Session#session{session_id = SessionId,
cipher_suite = CipherSuite,
@@ -1155,7 +1190,7 @@ handle_client_hello_extensions(RecordCB, Random, ClientCipherSuites,
#hello_extensions{renegotiation_info = Info,
srp = SRP,
ec_point_formats = ECCFormat,
- alpn = ALPN,
+ alpn = ALPN,
next_protocol_negotiation = NextProtocolNegotiation}, Version,
#ssl_options{secure_renegotiate = SecureRenegotation,
alpn_preferred_protocols = ALPNPreferredProtocols} = Opts,
@@ -1223,8 +1258,40 @@ handle_server_hello_extensions(RecordCB, Random, CipherSuite, Compression,
end.
select_version(RecordCB, ClientVersion, Versions) ->
- ServerVersion = RecordCB:highest_protocol_version(Versions),
- RecordCB:lowest_protocol_version(ClientVersion, ServerVersion).
+ do_select_version(RecordCB, ClientVersion, Versions).
+
+do_select_version(_, ClientVersion, []) ->
+ ClientVersion;
+do_select_version(RecordCB, ClientVersion, [Version | Versions]) ->
+ case RecordCB:is_higher(Version, ClientVersion) of
+ true ->
+ %% Version too high for client - keep looking
+ do_select_version(RecordCB, ClientVersion, Versions);
+ false ->
+ %% Version ok for client - look for a higher
+ do_select_version(RecordCB, ClientVersion, Versions, Version)
+ end.
+%%
+do_select_version(_, _, [], GoodVersion) ->
+ GoodVersion;
+do_select_version(
+ RecordCB, ClientVersion, [Version | Versions], GoodVersion) ->
+ BetterVersion =
+ case RecordCB:is_higher(Version, ClientVersion) of
+ true ->
+ %% Version too high for client
+ GoodVersion;
+ false ->
+ %% Version ok for client
+ case RecordCB:is_higher(Version, GoodVersion) of
+ true ->
+ %% Use higher version
+ Version;
+ false ->
+ GoodVersion
+ end
+ end,
+ do_select_version(RecordCB, ClientVersion, Versions, BetterVersion).
renegotiation_info(_, client, _, false) ->
#renegotiation_info{renegotiated_connection = undefined};
@@ -1324,7 +1391,7 @@ handle_renegotiation_info(_RecordCB, ConnectionStates, SecureRenegotation) ->
hello_extensions_list(#hello_extensions{renegotiation_info = RenegotiationInfo,
srp = SRP,
- hash_signs = HashSigns,
+ signature_algs = HashSigns,
ec_point_formats = EcPointFormats,
elliptic_curves = EllipticCurves,
alpn = ALPN,
@@ -1799,7 +1866,7 @@ dec_hello_extensions(<<?UINT16(?SIGNATURE_ALGORITHMS_EXT), ?UINT16(Len),
<<?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, Acc#hello_extensions{hash_signs =
+ dec_hello_extensions(Rest, Acc#hello_extensions{signature_algs =
#hash_sign_algos{hash_sign_algos = HashSignAlgos}});
dec_hello_extensions(<<?UINT16(?ELLIPTIC_CURVES_EXT), ?UINT16(Len),
@@ -1899,7 +1966,7 @@ from_2bytes(<<?UINT16(N), Rest/binary>>, Acc) ->
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 ->
+ 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;
@@ -2008,27 +2075,16 @@ is_member(Suite, SupportedSuites) ->
select_compression(_CompressionMetodes) ->
?NULL.
--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)).
-
-advertised_hash_signs({Major, Minor}) when Major >= 3 andalso Minor >= 3 ->
- 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 = crypto:supports(),
- HasECC = proplists:get_bool(ecdsa, proplists:get_value(public_keys, CryptoSupport)),
- Hashs = proplists:get_value(hashs, CryptoSupport),
- #hash_sign_algos{hash_sign_algos =
- lists:filter(fun({Hash, ecdsa}) -> HasECC andalso proplists:get_bool(Hash, Hashs);
- ({Hash, _}) -> proplists:get_bool(Hash, Hashs) end, HashSigns)};
-advertised_hash_signs(_) ->
+available_signature_algs(undefined, _, _) ->
+ undefined;
+available_signature_algs(SupportedHashSigns, {Major, Minor}, AllVersions) when Major >= 3 andalso Minor >= 3 ->
+ case tls_record:lowest_protocol_version(AllVersions) of
+ {3, 3} ->
+ #hash_sign_algos{hash_sign_algos = SupportedHashSigns};
+ _ ->
+ undefined
+ end;
+available_signature_algs(_, _, _) ->
undefined.
psk_secret(PSKIdentity, PSKLookup) ->
@@ -2072,12 +2128,9 @@ crl_check(OtpCert, Check, CertDbHandle, CertDbRef, {Callback, CRLDbHandle}, _) -
],
case dps_and_crls(OtpCert, Callback, CRLDbHandle, ext) of
no_dps ->
- case dps_and_crls(OtpCert, Callback, CRLDbHandle, same_issuer) of
- [] ->
- valid; %% No relevant CRL existed
- DpsAndCRls ->
- crl_check_same_issuer(OtpCert, Check, DpsAndCRls, Options)
- end;
+ crl_check_same_issuer(OtpCert, Check,
+ dps_and_crls(OtpCert, Callback, CRLDbHandle, same_issuer),
+ Options);
DpsAndCRLs -> %% This DP list may be empty if relevant CRLs existed
%% but could not be retrived, will result in {bad_cert, revocation_status_undetermined}
case public_key:pkix_crls_validate(OtpCert, DpsAndCRLs, Options) of
@@ -2126,3 +2179,25 @@ distpoints_lookup([DistPoint | Rest], Callback, CRLDbHandle) ->
CRLs ->
[{DistPoint, {CRL, public_key:der_decode('CertificateList', CRL)}} || CRL <- CRLs]
end.
+
+cert_sign(?rsaEncryption) ->
+ rsa;
+cert_sign(?'id-ecPublicKey') ->
+ ecdsa;
+cert_sign(?'id-dsa') ->
+ dsa;
+cert_sign(Alg) ->
+ {_, Sign} =public_key:pkix_sign_types(Alg),
+ Sign.
+
+is_acceptable_hash_sign({_, Sign} = Algos, Sign, _, SupportedHashSigns) ->
+ is_acceptable_hash_sign(Algos, SupportedHashSigns);
+is_acceptable_hash_sign(Algos,_, KeyExAlgo, SupportedHashSigns) when KeyExAlgo == dh_ecdsa;
+ KeyExAlgo == ecdh_rsa;
+ KeyExAlgo == ecdh_ecdsa ->
+ is_acceptable_hash_sign(Algos, SupportedHashSigns);
+is_acceptable_hash_sign(_,_,_,_) ->
+ false.
+is_acceptable_hash_sign(Algos, SupportedHashSigns) ->
+ lists:member(Algos, SupportedHashSigns).
+