%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2011-2014. 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.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
%% Description: Implements Password Based Encryption PKCS-5, RFC-2898
-module(pubkey_pbe).
-include("public_key.hrl").
-export([encode/4, decode/4, decrypt_parameters/1, encrypt_parameters/1]).
-export([pbdkdf1/4, pbdkdf2/7]).
-define(DEFAULT_SHA_MAC_KEYLEN, 20).
-define(ASN1_OCTET_STR_TAG, 4).
-define(IV_LEN, 8).
%%====================================================================
%% Internal application API
%%====================================================================
%%--------------------------------------------------------------------
-spec encode(binary(), string(), string(), term()) -> binary().
%%
%% Description: Performs password based encoding
%%--------------------------------------------------------------------
encode(Data, Password, "DES-CBC" = Cipher, KeyDevParams) ->
{Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams),
crypto:block_encrypt(des_cbc, Key, IV, pbe_pad(Data, KeyDevParams));
encode(Data, Password, "DES-EDE3-CBC" = Cipher, KeyDevParams) ->
{Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams),
<<Key1:8/binary, Key2:8/binary, Key3:8/binary>> = Key,
crypto:block_encrypt(des3_cbc, [Key1, Key2, Key3], IV, pbe_pad(Data));
encode(Data, Password, "RC2-CBC" = Cipher, KeyDevParams) ->
{Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams),
crypto:block_encrypt(rc2_cbc, Key, IV, pbe_pad(Data, KeyDevParams)).
%%--------------------------------------------------------------------
-spec decode(binary(), string(), string(), term()) -> binary().
%%
%% Description: Performs password based decoding
%%--------------------------------------------------------------------
decode(Data, Password,"DES-CBC"= Cipher, KeyDevParams) ->
{Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams),
crypto:block_decrypt(des_cbc, Key, IV, Data);
decode(Data, Password,"DES-EDE3-CBC" = Cipher, KeyDevParams) ->
{Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams),
<<Key1:8/binary, Key2:8/binary, Key3:8/binary>> = Key,
crypto:block_decrypt(des3_cbc, [Key1, Key2, Key3], IV, Data);
decode(Data, Password,"RC2-CBC"= Cipher, KeyDevParams) ->
{Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams),
crypto:block_decrypt(rc2_cbc, Key, IV, Data);
decode(Data, Password,"AES-128-CBC"= Cipher, IV) ->
%% PKCS5_SALT_LEN is 8 bytes
<<Salt:8/binary,_/binary>> = IV,
{Key, _} = password_to_key_and_iv(Password, Cipher, Salt),
crypto:block_decrypt(aes_cbc128, Key, IV, Data).
%%--------------------------------------------------------------------
-spec pbdkdf1(string(), iodata(), integer(), atom()) -> binary().
%%
%% Description: Implements password based decryption key derive function 1.
%% Exported mainly for testing purposes.
%%--------------------------------------------------------------------
pbdkdf1(_, _, 0, Acc) ->
Acc;
pbdkdf1(Password, Salt, Count, Hash) ->
Result = crypto:hash(Hash, [Password, Salt]),
do_pbdkdf1(Result, Count-1, Result, Hash).
%%--------------------------------------------------------------------
-spec pbdkdf2(string(), iodata(), integer(), integer(), fun(), atom(), integer())
-> binary().
%%
%% Description: Implements password based decryption key derive function 2.
%% Exported mainly for testing purposes.
%%--------------------------------------------------------------------
pbdkdf2(Password, Salt, Count, DerivedKeyLen, Prf, PrfHash, PrfOutputLen)->
NumBlocks = ceiling(DerivedKeyLen / PrfOutputLen),
NumLastBlockOctets = DerivedKeyLen - (NumBlocks - 1) * PrfOutputLen ,
blocks(NumBlocks, NumLastBlockOctets, 1, Password, Salt,
Count, Prf, PrfHash, PrfOutputLen, <<>>).
%%--------------------------------------------------------------------
-spec decrypt_parameters(#'EncryptedPrivateKeyInfo_encryptionAlgorithm'{}) ->
{Cipher::string(), #'PBES2-params'{}}.
%%
%% Description: Performs ANS1-decoding of encryption parameters.
%%--------------------------------------------------------------------
decrypt_parameters(#'EncryptedPrivateKeyInfo_encryptionAlgorithm'{
algorithm = Oid, parameters = Param}) ->
decrypt_parameters(Oid, decode_handle_open_type_wrapper(Param)).
%%--------------------------------------------------------------------
-spec encrypt_parameters({Cipher::string(), Params::term()}) ->
#'EncryptedPrivateKeyInfo_encryptionAlgorithm'{}.
%%
%% Description: Performs ANS1-decoding of encryption parameters.
%%--------------------------------------------------------------------
encrypt_parameters({Cipher, Params}) ->
encrypt_parameters(Cipher, Params).
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
password_to_key_and_iv(Password, _, #'PBES2-params'{} = Params) ->
{Salt, ItrCount, KeyLen, PseudoRandomFunction, PseudoHash, PseudoOtputLen, IV} =
key_derivation_params(Params),
<<Key:KeyLen/binary, _/binary>> =
pbdkdf2(Password, Salt, ItrCount, KeyLen, PseudoRandomFunction, PseudoHash, PseudoOtputLen),
{Key, IV};
password_to_key_and_iv(Password, _Cipher, {#'PBEParameter'{salt = Salt,
iterationCount = Count}, Hash}) ->
<<Key:8/binary, IV:8/binary, _/binary>>
= pbdkdf1(Password, Salt, Count, Hash),
{Key, IV};
password_to_key_and_iv(Password, Cipher, Salt) ->
KeyLen = derived_key_length(Cipher, undefined),
<<Key:KeyLen/binary, _/binary>> =
pem_encrypt(<<>>, Password, Salt, ceiling(KeyLen div 16), <<>>, md5),
%% Old PEM encryption does not use standard encryption method
%% pbdkdf1 and uses then salt as IV
{Key, Salt}.
pem_encrypt(_, _, _, 0, Acc, _) ->
Acc;
pem_encrypt(Prev, Password, Salt, Count, Acc, Hash) ->
Result = crypto:hash(Hash, [Prev, Password, Salt]),
pem_encrypt(Result, Password, Salt, Count-1 , <<Acc/binary, Result/binary>>, Hash).
do_pbdkdf1(_, 0, Acc, _) ->
Acc;
do_pbdkdf1(Prev, Count, Acc, Hash) ->
Result = crypto:hash(Hash, Prev),
do_pbdkdf1(Result, Count-1 , <<Result/binary, Acc/binary>>, Hash).
iv(#'PBES2-params_encryptionScheme'{algorithm = Algo,
parameters = ASN1IV})
when (Algo == ?'desCBC') or
(Algo == ?'des-EDE3-CBC') ->
<<?ASN1_OCTET_STR_TAG, ?IV_LEN, IV:?IV_LEN/binary>> = decode_handle_open_type_wrapper(ASN1IV),
IV;
iv(#'PBES2-params_encryptionScheme'{algorithm = ?'rc2CBC',
parameters = ASN1IV}) ->
{ok, #'RC2-CBC-Parameter'{iv = IV}}
= 'PKCS-FRAME':decode('RC2-CBC-Parameter', decode_handle_open_type_wrapper(ASN1IV)),
iolist_to_binary(IV).
blocks(1, N, Index, Password, Salt, Count, Prf, PrfHash, PrfLen, Acc) ->
<<XorSum:N/binary, _/binary>> = xor_sum(Password, Salt, Count, Index, Prf, PrfHash, PrfLen),
<<Acc/binary, XorSum/binary>>;
blocks(NumBlocks, N, Index, Password, Salt, Count, Prf, PrfHash, PrfLen, Acc) ->
XorSum = xor_sum(Password, Salt, Count, Index, Prf, PrfHash, PrfLen),
blocks(NumBlocks -1, N, Index +1, Password, Salt, Count, Prf, PrfHash,
PrfLen, <<Acc/binary, XorSum/binary>>).
xor_sum(Password, Salt, Count, Index, Prf, PrfHash, PrfLen) ->
Result = Prf(PrfHash, Password, [Salt,<<Index:32/unsigned-big-integer>>], PrfLen),
do_xor_sum(Prf, PrfHash, PrfLen, Result, Password, Count-1, Result).
do_xor_sum(_, _, _, _, _, 0, Acc) ->
Acc;
do_xor_sum(Prf, PrfHash, PrfLen, Prev, Password, Count, Acc)->
Result = Prf(PrfHash, Password, Prev, PrfLen),
do_xor_sum(Prf, PrfHash, PrfLen, Result, Password, Count-1, crypto:exor(Acc, Result)).
decrypt_parameters(?'id-PBES2', DekParams) ->
{ok, Params} = 'PKCS-FRAME':decode('PBES2-params', DekParams),
{cipher(Params#'PBES2-params'.encryptionScheme), Params};
decrypt_parameters(?'pbeWithSHA1AndRC2-CBC', DekParams) ->
{ok, Params} = 'PKCS-FRAME':decode('PBEParameter', DekParams),
{"RC2-CBC", {Params, sha}};
decrypt_parameters(?'pbeWithSHA1AndDES-CBC', DekParams) ->
{ok, Params} = 'PKCS-FRAME':decode('PBEParameter', DekParams),
{"DES-CBC", {Params, sha}};
decrypt_parameters(?'pbeWithMD5AndRC2-CBC', DekParams) ->
{ok, Params} = 'PKCS-FRAME':decode('PBEParameter', DekParams),
{"RC2-CBC", {Params, md5}};
decrypt_parameters(?'pbeWithMD5AndDES-CBC', DekParams) ->
{ok, Params} = 'PKCS-FRAME':decode('PBEParameter', DekParams),
{"DES-CBC", {Params, md5}}.
encrypt_parameters(_Cipher, #'PBES2-params'{} = Params) ->
{ok, Der} ='PKCS-FRAME':encode('PBES2-params', Params),
#'EncryptedPrivateKeyInfo_encryptionAlgorithm'{
algorithm = ?'id-PBES2',
parameters = encode_handle_open_type_wrapper(Der)};
encrypt_parameters(Cipher, {#'PBEParameter'{} = Params, Hash}) ->
{ok, Der} ='PKCS-FRAME':encode('PBEParameter', Params),
#'EncryptedPrivateKeyInfo_encryptionAlgorithm'{
algorithm = pbe1_oid(Cipher, Hash),
parameters = encode_handle_open_type_wrapper(Der)}.
pbe1_oid("RC2-CBC", sha) ->
?'pbeWithSHA1AndRC2-CBC';
pbe1_oid("DES-CBC", sha) ->
?'pbeWithSHA1AndDES-CBC';
pbe1_oid("RC2-CBC", md5) ->
?'pbeWithMD5AndRC2-CBC';
pbe1_oid("DES-CBC", md5) ->
?'pbeWithMD5AndDES-CBC'.
pbe_pad(Data, {#'PBEParameter'{}, _}) ->
pbe_pad(Data);
pbe_pad(Data, #'PBES2-params'{}) ->
pbe_pad(Data);
pbe_pad(Data, _) ->
Data.
pbe_pad(Data) ->
N = 8 - (erlang:byte_size(Data) rem 8),
Pad = list_to_binary(lists:duplicate(N, N)),
<<Data/binary, Pad/binary>>.
key_derivation_params(#'PBES2-params'{keyDerivationFunc = KeyDerivationFunc,
encryptionScheme = EncScheme}) ->
#'PBES2-params_keyDerivationFunc'{algorithm = ?'id-PBKDF2',
parameters =
#'PBKDF2-params'{salt = {specified, OctetSalt},
iterationCount = Count,
keyLength = Length,
prf = Prf}} = KeyDerivationFunc,
#'PBES2-params_encryptionScheme'{algorithm = Algo} = EncScheme,
{PseudoRandomFunction, PseudoHash, PseudoOtputLen} = pseudo_random_function(Prf),
KeyLen = derived_key_length(Algo, Length),
{OctetSalt, Count, KeyLen,
PseudoRandomFunction, PseudoHash, PseudoOtputLen, iv(EncScheme)}.
%% This function currently matches a tuple that ougth to be the value
%% ?'id-hmacWithSHA1, but we need some kind of ASN1-fix for this.
pseudo_random_function(#'PBKDF2-params_prf'{algorithm =
{_,_, _,'id-hmacWithSHA1'}}) ->
{fun crypto:hmac/4, sha, pseudo_output_length(?'id-hmacWithSHA1')};
pseudo_random_function(#'PBKDF2-params_prf'{algorithm = ?'id-hmacWithSHA1'}) ->
{fun crypto:hmac/4, sha, pseudo_output_length(?'id-hmacWithSHA1')}.
pseudo_output_length(?'id-hmacWithSHA1') ->
?DEFAULT_SHA_MAC_KEYLEN.
derived_key_length(_, Len) when is_integer(Len) ->
Len;
derived_key_length(Cipher,_) when (Cipher == ?'desCBC') or
(Cipher == "DES-CBC") ->
8;
derived_key_length(Cipher,_) when (Cipher == ?'rc2CBC') or
(Cipher == "RC2-CBC") ->
16;
derived_key_length(Cipher,_) when (Cipher == ?'des-EDE3-CBC') or
(Cipher == "DES-EDE3-CBC") ->
24;
derived_key_length(Cipher,_) when (Cipher == "AES-128-CBC") ->
16.
cipher(#'PBES2-params_encryptionScheme'{algorithm = ?'desCBC'}) ->
"DES-CBC";
cipher(#'PBES2-params_encryptionScheme'{algorithm = ?'des-EDE3-CBC'}) ->
"DES-EDE3-CBC";
cipher(#'PBES2-params_encryptionScheme'{algorithm = ?'rc2CBC'}) ->
"RC2-CBC".
ceiling(Float) ->
erlang:round(Float + 0.5).
decode_handle_open_type_wrapper({asn1_OPENTYPE, Type}) ->
Type.
encode_handle_open_type_wrapper(Type) ->
{asn1_OPENTYPE, Type}.
