%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2008-2010. 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: Functions that call the crypto driver.
-module(pubkey_crypto).
-include("public_key.hrl").
-export([encrypt_public/3, decrypt_private/3,
encrypt_private/3, decrypt_public/3,
sign/2, sign/3, verify/5, gen_key/2]).
-define(UINT32(X), X:32/unsigned-big-integer).
%%====================================================================
%% Internal application API
%%====================================================================
%%--------------------------------------------------------------------
%% Function: encrypt(PlainText, Key, Padding) -> Encrypted
%%
%% PlainText = binary()
%% Key = rsa_public_key() | rsa_private_key()
%% Padding = rsa_pkcs1_padding | rsa_pkcs1_oaep_padding
%% Encrypted = binary()
%%
%% Description: Public key encrypts PlainText.
%%--------------------------------------------------------------------
encrypt_public(PlainText, #'RSAPublicKey'{modulus=N,publicExponent=E},
Padding) ->
crypto:rsa_public_encrypt(PlainText, [crypto:mpint(E),crypto:mpint(N)],
Padding);
encrypt_public(PlainText, #'RSAPrivateKey'{modulus=N,publicExponent=E},
Padding) ->
crypto:rsa_public_encrypt(PlainText, [crypto:mpint(E),crypto:mpint(N)],
Padding).
encrypt_private(PlainText, #'RSAPrivateKey'{modulus = N,
publicExponent = E,
privateExponent = D}, Padding) ->
crypto:rsa_private_encrypt(PlainText, [crypto:mpint(E),
crypto:mpint(N),
crypto:mpint(D)], Padding).
%%--------------------------------------------------------------------
%% Function: decrypt(CipherText, Key) -> PlainText
%%
%% ChipherText = binary()
%% Key = rsa_private_key()
%% Padding = rsa_pkcs1_padding | rsa_pkcs1_oaep_padding
%% PlainText = binary()
%%
%% Description: Uses private key to decrypt public key encrypted data.
%%--------------------------------------------------------------------
decrypt_private(CipherText,
#'RSAPrivateKey'{modulus = N,publicExponent = E,
privateExponent = D},
Padding) ->
crypto:rsa_private_decrypt(CipherText,
[crypto:mpint(E), crypto:mpint(N),
crypto:mpint(D)], Padding).
decrypt_public(CipherText, #'RSAPublicKey'{modulus = N, publicExponent = E},
Padding) ->
crypto:rsa_public_decrypt(CipherText,[crypto:mpint(E), crypto:mpint(N)],
Padding);
decrypt_public(CipherText, #'RSAPrivateKey'{modulus = N, publicExponent = E},
Padding) ->
crypto:rsa_public_decrypt(CipherText,[crypto:mpint(E), crypto:mpint(N)],
Padding).
%%--------------------------------------------------------------------
%% Function: sign(PlainText, Key) ->
%% sign(DigestType, PlainText, Key) -> Signature
%%
%% DigestType = sha | md5
%% PlainText = binary()
%% Key = rsa_private_key() | dsa_private_key()
%% Signature = binary()
%%
%% Description: Signs PlainText using Key.
%%--------------------------------------------------------------------
sign(PlainText, Digest) ->
sign(sha, PlainText, Digest).
sign(DigestType, PlainText, #'RSAPrivateKey'{modulus = N, publicExponent = E,
privateExponent = D}) ->
crypto:rsa_sign(DigestType, sized_binary(PlainText), [crypto:mpint(E),
crypto:mpint(N),
crypto:mpint(D)]);
sign(sha, PlainText, #'DSAPrivateKey'{p = P, q = Q, g = G, x = X}) ->
crypto:dss_sign(sized_binary(PlainText),
[crypto:mpint(P), crypto:mpint(Q),
crypto:mpint(G), crypto:mpint(X)]).
%%--------------------------------------------------------------------
%% Function: verify(DigestType, PlainText, Signature, Key) -> true | false
%%
%% DigestType = sha | md5
%% PlainText = binary()
%% Signature = binary()
%% Key = rsa_public_key() | dsa_public_key()
%%
%% Description: Verifies the signature <Signature>.
%%--------------------------------------------------------------------
verify(DigestType, PlainText, Signature,
#'RSAPublicKey'{modulus = Mod, publicExponent = Exp}, _) ->
crypto:rsa_verify(DigestType,
sized_binary(PlainText),
sized_binary(Signature),
[crypto:mpint(Exp), crypto:mpint(Mod)]);
verify(sha, PlainText, Signature, Key, #'Dss-Parms'{p = P, q = Q, g = G}) ->
crypto:dss_verify(sized_binary(PlainText),
sized_binary(Signature),
[crypto:mpint(P), crypto:mpint(Q),
crypto:mpint(G), crypto:mpint(Key)]).
%%--------------------------------------------------------------------
%% Function: gen_key(Type, Params) ->
%% Type = diffie_hellman
%% Params = [P,G] | [Y, P, G]
%% Description: Generates keys.
%% -----------------------------------------------------------------
gen_key(diffie_hellman, [Y, P, G]) ->
crypto:dh_generate_key(crypto:mpint(Y), [crypto:mpint(P),
crypto:mpint(G)]);
gen_key(diffie_hellman, [P, G]) ->
crypto:dh_generate_key([crypto:mpint(P), crypto:mpint(G)]).
%%% TODO: Support rsa, dss key_gen
%%--------------------------------------------------------------------
%%% Internal functions
%%--------------------------------------------------------------------
sized_binary(Binary) when is_binary(Binary) ->
Size = size(Binary),
<<?UINT32(Size), Binary/binary>>;
sized_binary(List) ->
sized_binary(list_to_binary(List)).
