%% %% %CopyrightBegin% %% %% Copyright Ericsson AB 2011-2011. 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% %% %% Description: Implements Password Based Encryption PKCS-5, RFC-2898 -module(pubkey_pbe). -include("public_key.hrl"). -export([encode/4, decode/4, decrypt_parameters/1]). -export([pbdkdf1/4, pbdkdf2/6]). -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:des_cbc_encrypt(Key, IV, Data); encode(Data, Password, "DES-EDE3-CBC" = Cipher, KeyDevParams) -> {Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams), <> = Key, crypto:des_ede3_cbc_encrypt(Key1, Key2, Key3, IV, Data); encode(Data, Password, "RC2-CBC" = Cipher, KeyDevParams) -> {Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams), crypto:rc2_cbc_encrypt(Key, IV, Data). %%-------------------------------------------------------------------- -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:des_cbc_decrypt(Key, IV, Data); decode(Data, Password,"DES-EDE3-CBC" = Cipher, KeyDevParams) -> {Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams), <> = Key, crypto:des_ede3_cbc_decrypt(Key1, Key2, Key3, IV, Data); decode(Data, Password,"RC2-CBC"= Cipher, KeyDevParams) -> {Key, IV} = password_to_key_and_iv(Password, Cipher, KeyDevParams), crypto:rc2_cbc_decrypt(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([Password, Salt]), do_pbdkdf1(Result, Count-1, Result, Hash). %%-------------------------------------------------------------------- -spec pbdkdf2(string(), iodata(), integer(), integer(), fun(), integer()) -> binary(). %% %% Description: Implements password based decryption key derive function 2. %% Exported mainly for testing purposes. %%-------------------------------------------------------------------- pbdkdf2(Password, Salt, Count, DerivedKeyLen, Prf, PrfOutputLen)-> NumBlocks = ceiling(DerivedKeyLen / PrfOutputLen), NumLastBlockOctets = DerivedKeyLen - (NumBlocks - 1) * PrfOutputLen , blocks(NumBlocks, NumLastBlockOctets, 1, Password, Salt, Count, Prf, 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, Param). %%-------------------------------------------------------------------- %%% Internal functions %%-------------------------------------------------------------------- password_to_key_and_iv(Password, _, #'PBES2-params'{} = Params) -> {Salt, ItrCount, KeyLen, PseudoRandomFunction, PseudoOtputLen, IV} = key_derivation_params(Params), <> = pbdkdf2(Password, Salt, ItrCount, KeyLen, PseudoRandomFunction, PseudoOtputLen), {Key, IV}; password_to_key_and_iv(Password, Cipher, Salt) -> KeyLen = derived_key_length(Cipher, undefined), <> = 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([Prev, Password, Salt]), pem_encrypt(Result, Password, Salt, Count-1 , <>, Hash). do_pbdkdf1(_, 0, Acc, _) -> Acc; do_pbdkdf1(Prev, Count, Acc, Hash) -> Result = crypto:Hash(Prev), do_pbdkdf1(Result, Count-1 , <>, Hash). iv(#'PBES2-params_encryptionScheme'{algorithm = Algo, parameters = ASNIV}) when (Algo == ?'desCBC') or (Algo == ?'des-EDE3-CBC') -> %% This is an so called open ASN1-type that in this %% case will be an octet-string of length 8 <> = ASNIV, IV; iv(#'PBES2-params_encryptionScheme'{algorithm = ?'rc2CBC', parameters = ASN1IV}) -> {ok, #'RC2-CBC-Parameter'{iv = IV}} = 'PKCS-FRAME':decode('RC2-CBC-Parameter', ASN1IV), iolist_to_binary(IV). blocks(1, N, Index, Password, Salt, Count, Prf, PrfLen, Acc) -> <> = xor_sum(Password, Salt, Count, Index, Prf, PrfLen), <>; blocks(NumBlocks, N, Index, Password, Salt, Count, Prf, PrfLen, Acc) -> XorSum = xor_sum(Password, Salt, Count, Index, Prf, PrfLen), blocks(NumBlocks -1, N, Index +1, Password, Salt, Count, Prf, PrfLen, <>). xor_sum(Password, Salt, Count, Index, Prf, PrfLen) -> Result = Prf(Password, [Salt,<>], PrfLen), do_xor_sum(Prf, PrfLen, Result, Password, Count-1, Result). do_xor_sum(_, _, _, _, 0, Acc) -> Acc; do_xor_sum(Prf, PrfLen, Prev, Password, Count, Acc)-> Result = Prf(Password, Prev, PrfLen), do_xor_sum(Prf, 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}. 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, PseudoOtputLen} = pseudo_random_function(Prf), KeyLen = derived_key_length(Algo, Length), {OctetSalt, Count, KeyLen, PseudoRandomFunction, 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:sha_mac/3, 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. 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).