aboutsummaryrefslogtreecommitdiffstats
path: root/lib/crypto/src/crypto.erl
blob: e3b921f9fa4301e6d0ce34767c589c0847931f12 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1999-2011. 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%
%%

%% Purpose : Main Crypto API module.

-module(crypto).

-export([start/0, stop/0, info/0, info_lib/0, version/0]).
-export([md4/1, md4_init/0, md4_update/2, md4_final/1]).
-export([md5/1, md5_init/0, md5_update/2, md5_final/1]).
-export([sha/1, sha_init/0, sha_update/2, sha_final/1]).
%-export([sha256/1, sha256_init/0, sha256_update/2, sha256_final/1]).
%-export([sha512/1, sha512_init/0, sha512_update/2, sha512_final/1]).
-export([md5_mac/2, md5_mac_96/2, sha_mac/2, sha_mac_96/2]).
-export([hmac_init/2, hmac_update/2, hmac_final/1, hmac_final_n/2]).
-export([des_cbc_encrypt/3, des_cbc_decrypt/3, des_cbc_ivec/1]).
-export([des_ecb_encrypt/2, des_ecb_decrypt/2]).
-export([des_cfb_encrypt/3, des_cfb_decrypt/3, des_cfb_ivec/2]).
-export([des3_cbc_encrypt/5, des3_cbc_decrypt/5]).
-export([des3_cfb_encrypt/5, des3_cfb_decrypt/5]).
-export([blowfish_ecb_encrypt/2, blowfish_ecb_decrypt/2]).
-export([blowfish_cbc_encrypt/3, blowfish_cbc_decrypt/3]).
-export([blowfish_cfb64_encrypt/3, blowfish_cfb64_decrypt/3]).
-export([blowfish_ofb64_encrypt/3]).
-export([des_ede3_cbc_encrypt/5, des_ede3_cbc_decrypt/5]).
-export([aes_cfb_128_encrypt/3, aes_cfb_128_decrypt/3]).
-export([exor/2]).
-export([rc4_encrypt/2, rc4_set_key/1, rc4_encrypt_with_state/2]).
-export([rc2_40_cbc_encrypt/3, rc2_40_cbc_decrypt/3]).
-export([dss_verify/3, dss_verify/4, rsa_verify/3, rsa_verify/4]).
-export([dss_sign/2, dss_sign/3, rsa_sign/2, rsa_sign/3]).
-export([rsa_public_encrypt/3, rsa_private_decrypt/3]).
-export([rsa_private_encrypt/3, rsa_public_decrypt/3]).
-export([dh_generate_key/1, dh_generate_key/2, dh_compute_key/3]).
-export([rand_bytes/1, rand_bytes/3, rand_uniform/2]).
-export([strong_rand_bytes/1, strong_rand_mpint/3]).
-export([mod_exp/3, mpint/1, erlint/1]).
%% -export([idea_cbc_encrypt/3, idea_cbc_decrypt/3]).
-export([aes_cbc_128_encrypt/3, aes_cbc_128_decrypt/3]).
-export([aes_cbc_256_encrypt/3, aes_cbc_256_decrypt/3]).
-export([aes_cbc_ivec/1]).
-export([aes_ctr_encrypt/3, aes_ctr_decrypt/3]).
-export([aes_ctr_stream_init/2, aes_ctr_stream_encrypt/2, aes_ctr_stream_decrypt/2]).

-export([dh_generate_parameters/2, dh_check/1]). %% Testing see below


-define(FUNC_LIST, [md4, md4_init, md4_update, md4_final,
		    md5, md5_init, md5_update, md5_final,
		    sha, sha_init, sha_update, sha_final,
%% 		    sha256, sha256_init, sha256_update, sha256_final,
%% 		    sha512, sha512_init, sha512_update, sha512_final,
		    md5_mac,  md5_mac_96,
		    sha_mac,  sha_mac_96,
                    sha_mac_init, sha_mac_update, sha_mac_final,
		    des_cbc_encrypt, des_cbc_decrypt,
		    des_cfb_encrypt, des_cfb_decrypt,
		    des_ecb_encrypt, des_ecb_decrypt,
		    des_ede3_cbc_encrypt, des_ede3_cbc_decrypt,
		    des_ede3_cfb_encrypt, des_ede3_cfb_decrypt,
		    aes_cfb_128_encrypt, aes_cfb_128_decrypt,
		    rand_bytes,
		    strong_rand_bytes,
		    strong_rand_mpint,
		    rand_uniform,
		    mod_exp,
		    dss_verify,dss_sign,
		    rsa_verify,rsa_sign,
		    rsa_public_encrypt,rsa_private_decrypt, 
		    rsa_private_encrypt,rsa_public_decrypt, 
		    dh_generate_key, dh_compute_key,
		    aes_cbc_128_encrypt, aes_cbc_128_decrypt,
		    exor,
		    rc4_encrypt, rc4_set_key, rc4_encrypt_with_state,
		    rc2_40_cbc_encrypt, rc2_40_cbc_decrypt,
		    %% idea_cbc_encrypt, idea_cbc_decrypt,
		    aes_cbc_256_encrypt, aes_cbc_256_decrypt,
            aes_ctr_encrypt, aes_ctr_decrypt,
                    aes_ctr_stream_init, aes_ctr_stream_encrypt, aes_ctr_stream_decrypt,
		    info_lib]).

-type rsa_digest_type() :: 'md5' | 'sha'.
-type dss_digest_type() :: 'none' | 'sha'.
-type crypto_integer() :: binary() | integer().

-define(nif_stub,nif_stub_error(?LINE)).

-on_load(on_load/0).

-define(CRYPTO_NIF_VSN,101).

on_load() ->
    LibBaseName = "crypto",
    PrivDir = code:priv_dir(crypto),
    LibName = case erlang:system_info(build_type) of
		  opt ->
		      LibBaseName;
		  Type ->
		      LibTypeName = LibBaseName ++ "."  ++ atom_to_list(Type),
		      case (filelib:wildcard(
			      filename:join(
				[PrivDir,
				 "lib",
				 LibTypeName ++ "*"])) /= []) orelse
			  (filelib:wildcard(
			     filename:join(
			       [PrivDir,
				"lib", 
				erlang:system_info(system_architecture),
				LibTypeName ++ "*"])) /= []) of
			  true -> LibTypeName;
			  false -> LibBaseName
		      end
	      end,
    Lib = filename:join([PrivDir, "lib", LibName]),
    Status = case erlang:load_nif(Lib, ?CRYPTO_NIF_VSN) of
		 ok -> ok;
		 {error, {load_failed, _}}=Error1 ->
		     ArchLibDir = 
			 filename:join([PrivDir, "lib", 
					erlang:system_info(system_architecture)]),
		     Candidate =
			 filelib:wildcard(filename:join([ArchLibDir,LibName ++ "*" ])),
		     case Candidate of
			 [] -> Error1;
			 _ ->
			     ArchLib = filename:join([ArchLibDir, LibName]),
			     erlang:load_nif(ArchLib, ?CRYPTO_NIF_VSN)
		     end;
		 Error1 -> Error1
	     end,
    case Status of
	ok -> ok;
	{error, {E, Str}} ->
	    error_logger:error_msg("Unable to load crypto library. Failed with error:~n\"~p, ~s\"~n"
				   "OpenSSL might not be installed on this system.~n",[E,Str]),
	    Status
    end.

nif_stub_error(Line) ->
    erlang:nif_error({nif_not_loaded,module,?MODULE,line,Line}).

start() ->
    application:start(crypto).

stop() ->
    application:stop(crypto).

info() ->
    ?FUNC_LIST.

info_lib() -> ?nif_stub.

%% Crypto app version history:
%% (no version): Driver implementation
%% 2.0         : NIF implementation, requires OTP R14
version() -> ?CRYPTO_VSN.
     
%% Below Key and Data are binaries or IO-lists. IVec is a binary.
%% Output is always a binary. Context is a binary.

%%
%%  MESSAGE DIGESTS
%%

%%
%%  MD5
%%

-spec md5(iodata()) -> binary().
-spec md5_init() -> binary().
-spec md5_update(binary(), iodata()) -> binary().
-spec md5_final(binary()) -> binary().

md5(_Data) -> ?nif_stub.
md5_init() -> ?nif_stub.
md5_update(_Context, _Data) -> ?nif_stub.
md5_final(_Context) -> ?nif_stub.

%%
%%  MD4
%%
-spec md4(iodata()) -> binary().
-spec md4_init() -> binary().
-spec md4_update(binary(), iodata()) -> binary().
-spec md4_final(binary()) -> binary().

md4(_Data) -> ?nif_stub.
md4_init() -> ?nif_stub.
md4_update(_Context, _Data) -> ?nif_stub.
md4_final(_Context) -> ?nif_stub.

%%
%% SHA
%%
-spec sha(iodata()) -> binary().
-spec sha_init() -> binary().
-spec sha_update(binary(), iodata()) -> binary().
-spec sha_final(binary()) -> binary().

sha(_Data) -> ?nif_stub.
sha_init() -> ?nif_stub.
sha_update(_Context, _Data) -> ?nif_stub.
sha_final(_Context) -> ?nif_stub.


%%
%%  MESSAGE AUTHENTICATION CODES
%%

%%
%%  HMAC (multiple hash options)
%%
-spec hmac_init(atom(), iodata()) -> binary().                             
-spec hmac_update(binary(), iodata()) -> binary().
-spec hmac_final(binary()) -> binary().                             
-spec hmac_final_n(binary(), integer()) -> binary().                             

hmac_init(_Type, _Key) -> ?nif_stub.
hmac_update(_Context, _Data) -> ? nif_stub.
hmac_final(_Context) -> ? nif_stub.
hmac_final_n(_Context, _HashLen) -> ? nif_stub.
     
%%
%%  MD5_MAC
%%
-spec md5_mac(iodata(), iodata()) -> binary().
-spec md5_mac_96(iodata(), iodata()) -> binary().

md5_mac(Key, Data) ->
    md5_mac_n(Key,Data,16).

md5_mac_96(Key, Data) ->
    md5_mac_n(Key,Data,12).

md5_mac_n(_Key,_Data,_MacSz) -> ?nif_stub.
    
%%
%%  SHA_MAC
%%
-spec sha_mac(iodata(), iodata()) -> binary().
-spec sha_mac_96(iodata(), iodata()) -> binary().

sha_mac(Key, Data) ->
    sha_mac_n(Key,Data,20).

sha_mac_96(Key, Data) ->
    sha_mac_n(Key,Data,12).

sha_mac_n(_Key,_Data,_MacSz) -> ?nif_stub.

%%
%% CRYPTO FUNCTIONS
%%

%%
%% DES - in cipher block chaining mode (CBC)
%%
-spec des_cbc_encrypt(iodata(), binary(), iodata()) -> binary().
-spec des_cbc_decrypt(iodata(), binary(), iodata()) -> binary().

des_cbc_encrypt(Key, IVec, Data) ->
    des_cbc_crypt(Key, IVec, Data, true).

des_cbc_decrypt(Key, IVec, Data) ->
    des_cbc_crypt(Key, IVec, Data, false).

des_cbc_crypt(_Key, _IVec, _Data, _IsEncrypt) -> ?nif_stub.

%%
%% dec_cbc_ivec(Data) -> binary()
%%
%% Returns the IVec to be used in the next iteration of 
%% des_cbc_[encrypt|decrypt].
%%
-spec des_cbc_ivec(iodata()) -> binary().

des_cbc_ivec(Data) when is_binary(Data) -> 
    {_, IVec} = split_binary(Data, size(Data) - 8),
    IVec;
des_cbc_ivec(Data) when is_list(Data) ->
    des_cbc_ivec(list_to_binary(Data)).

%%
%% DES - in 8-bits cipher feedback mode (CFB)
%%
-spec des_cfb_encrypt(iodata(), binary(), iodata()) -> binary().
-spec des_cfb_decrypt(iodata(), binary(), iodata()) -> binary().

des_cfb_encrypt(Key, IVec, Data) ->
    des_cfb_crypt(Key, IVec, Data, true).

des_cfb_decrypt(Key, IVec, Data) ->
    des_cfb_crypt(Key, IVec, Data, false).

des_cfb_crypt(_Key, _IVec, _Data, _IsEncrypt) -> ?nif_stub.

%%
%% dec_cfb_ivec(IVec, Data) -> binary()
%%
%% Returns the IVec to be used in the next iteration of
%% des_cfb_[encrypt|decrypt].
%%
-spec des_cfb_ivec(iodata(), iodata()) -> binary().

des_cfb_ivec(IVec, Data) ->
    IVecAndData = list_to_binary([IVec, Data]),
    {_, NewIVec} = split_binary(IVecAndData, byte_size(IVecAndData) - 8),
    NewIVec.

%%
%% DES - in electronic codebook mode (ECB)
%%
-spec des_ecb_encrypt(iodata(), iodata()) -> binary().
-spec des_ecb_decrypt(iodata(), iodata()) -> binary().

des_ecb_encrypt(Key, Data) ->
    des_ecb_crypt(Key, Data, true).
des_ecb_decrypt(Key, Data) ->
    des_ecb_crypt(Key, Data, false).
des_ecb_crypt(_Key, _Data, _IsEncrypt) -> ?nif_stub.

%%
%% DES3 - in cipher block chaining mode (CBC)
%%
-spec des3_cbc_encrypt(iodata(), iodata(), iodata(), binary(), iodata()) ->
			     binary().
-spec des3_cbc_decrypt(iodata(), iodata(), iodata(), binary(), iodata()) ->
			     binary().

des3_cbc_encrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cbc_encrypt(Key1, Key2, Key3, IVec, Data).
des_ede3_cbc_encrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cbc_crypt(Key1, Key2, Key3, IVec, Data, true).

des3_cbc_decrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cbc_decrypt(Key1, Key2, Key3, IVec, Data).
des_ede3_cbc_decrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cbc_crypt(Key1, Key2, Key3, IVec, Data, false).

des_ede3_cbc_crypt(_Key1, _Key2, _Key3, _IVec, _Data, _IsEncrypt) -> ?nif_stub.    

%%
%% DES3 - in 8-bits cipher feedback mode (CFB)
%%
-spec des3_cfb_encrypt(iodata(), iodata(), iodata(), binary(), iodata()) ->
			     binary().
-spec des3_cfb_decrypt(iodata(), iodata(), iodata(), binary(), iodata()) ->
			     binary().

des3_cfb_encrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cfb_encrypt(Key1, Key2, Key3, IVec, Data).
des_ede3_cfb_encrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cfb_crypt(Key1, Key2, Key3, IVec, Data, true).

des3_cfb_decrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cfb_decrypt(Key1, Key2, Key3, IVec, Data).
des_ede3_cfb_decrypt(Key1, Key2, Key3, IVec, Data) ->
    des_ede3_cfb_crypt(Key1, Key2, Key3, IVec, Data, false).

des_ede3_cfb_crypt(_Key1, _Key2, _Key3, _IVec, _Data, _IsEncrypt) -> ?nif_stub.

%%
%% Blowfish
%%
-spec blowfish_ecb_encrypt(iodata(), iodata()) -> binary().
-spec blowfish_ecb_decrypt(iodata(), iodata()) -> binary().
-spec blowfish_cbc_encrypt(iodata(), binary(), iodata()) -> binary().
-spec blowfish_cbc_decrypt(iodata(), binary(), iodata()) -> binary().
-spec blowfish_cfb64_encrypt(iodata(), binary(), iodata()) -> binary().
-spec blowfish_cfb64_decrypt(iodata(), binary(), iodata()) -> binary().
-spec blowfish_ofb64_encrypt(iodata(), binary(), iodata()) -> binary().

blowfish_ecb_encrypt(Key, Data) ->
    bf_ecb_crypt(Key,Data, true).

blowfish_ecb_decrypt(Key, Data) ->
    bf_ecb_crypt(Key,Data, false).

bf_ecb_crypt(_Key,_Data,_IsEncrypt) -> ?nif_stub.

blowfish_cbc_encrypt(Key, IVec, Data) ->
    bf_cbc_crypt(Key,IVec,Data,true).

blowfish_cbc_decrypt(Key, IVec, Data) ->
    bf_cbc_crypt(Key,IVec,Data,false).

bf_cbc_crypt(_Key,_IVec,_Data,_IsEncrypt) -> ?nif_stub.    

blowfish_cfb64_encrypt(Key, IVec, Data) ->
    bf_cfb64_crypt(Key, IVec, Data, true).

blowfish_cfb64_decrypt(Key, IVec, Data) ->
    bf_cfb64_crypt(Key, IVec, Data, false).

bf_cfb64_crypt(_Key, _IVec, _Data, _IsEncrypt) -> ?nif_stub.

blowfish_ofb64_encrypt(_Key, _IVec, _Data) -> ?nif_stub.

%%
%% AES in cipher feedback mode (CFB)
%%
-spec aes_cfb_128_encrypt(iodata(), binary(), iodata()) -> binary().
-spec aes_cfb_128_decrypt(iodata(), binary(), iodata()) -> binary().

aes_cfb_128_encrypt(Key, IVec, Data) ->
    aes_cfb_128_crypt(Key, IVec, Data, true).

aes_cfb_128_decrypt(Key, IVec, Data) ->
    aes_cfb_128_crypt(Key, IVec, Data, false).

aes_cfb_128_crypt(_Key, _IVec, _Data, _IsEncrypt) -> ?nif_stub.     


%% 
%% RAND - pseudo random numbers using RN_ functions in crypto lib
%%
-spec rand_bytes(non_neg_integer()) -> binary().
-spec strong_rand_bytes(non_neg_integer()) -> binary().
-spec rand_uniform(crypto_integer(), crypto_integer()) ->
			  crypto_integer().
-spec strong_rand_mpint(Bits::non_neg_integer(),
			Top::-1..1,
			Bottom::0..1) -> binary().

rand_bytes(_Bytes) -> ?nif_stub.

strong_rand_bytes(Bytes) ->
    case strong_rand_bytes_nif(Bytes) of
        false -> erlang:error(low_entropy);
        Bin -> Bin
    end.
strong_rand_bytes_nif(_Bytes) -> ?nif_stub.

rand_bytes(_Bytes, _Topmask, _Bottommask) -> ?nif_stub.

strong_rand_mpint(Bits, Top, Bottom) -> 
    case strong_rand_mpint_nif(Bits,Top,Bottom) of
        false -> erlang:error(low_entropy);
        Bin -> Bin
    end.
strong_rand_mpint_nif(_Bits, _Top, _Bottom) -> ?nif_stub.


rand_uniform(From,To) when is_binary(From), is_binary(To) ->
    case rand_uniform_nif(From,To) of
	<<Len:32/integer, MSB, Rest/binary>> when MSB > 127 ->
	    <<(Len + 1):32/integer, 0, MSB, Rest/binary>>;
	Whatever ->
	    Whatever
    end;
rand_uniform(From,To) when is_integer(From),is_integer(To) ->
    if From < 0 -> 
	    rand_uniform_pos(0, To - From) + From;
       true ->
	    rand_uniform_pos(From, To)
    end.

rand_uniform_pos(From,To) when From < To ->
    BinFrom = mpint(From),
    BinTo = mpint(To),
    case rand_uniform(BinFrom, BinTo) of
        Result when is_binary(Result) ->
            erlint(Result);
        Other ->
            Other
    end;
rand_uniform_pos(_,_) ->
    error(badarg).

rand_uniform_nif(_From,_To) -> ?nif_stub.     

%%
%% mod_exp - utility for rsa generation
%%
mod_exp(Base, Exponent, Modulo)
  when is_integer(Base), is_integer(Exponent), is_integer(Modulo) ->
    erlint(mod_exp(mpint(Base), mpint(Exponent), mpint(Modulo)));

mod_exp(Base, Exponent, Modulo) ->
    case mod_exp_nif(Base,Exponent,Modulo) of
	<<Len:32/integer, MSB, Rest/binary>> when MSB > 127 ->
	    <<(Len + 1):32/integer, 0, MSB, Rest/binary>>;
	Whatever ->
	    Whatever
    end.

mod_exp_nif(_Base,_Exp,_Mod) -> ?nif_stub.    

%%
%% DSS, RSA - verify
%%
-spec dss_verify(binary(), binary(), [binary()]) -> boolean().
-spec dss_verify(dss_digest_type(), binary(), binary(), [binary()]) -> boolean().
-spec rsa_verify(binary(), binary(), [binary()]) -> boolean().
-spec rsa_verify(rsa_digest_type(), binary(), binary(), [binary()]) ->
			boolean().

%% Key = [P,Q,G,Y]   P,Q,G=DSSParams  Y=PublicKey
dss_verify(Data,Signature,Key) ->
    dss_verify(sha, Data, Signature, Key).    
dss_verify(_Type,_Data,_Signature,_Key) -> ?nif_stub.    

% Key = [E,N]  E=PublicExponent N=PublicModulus
rsa_verify(Data,Signature,Key) ->
    rsa_verify(sha, Data,Signature,Key).
rsa_verify(_Type,_Data,_Signature,_Key) -> ?nif_stub.


%%
%% DSS, RSA - sign
%%
%% Key = [P,Q,G,X]   P,Q,G=DSSParams  X=PrivateKey
-spec dss_sign(binary(), [binary()]) -> binary().
-spec dss_sign(dss_digest_type(), binary(), [binary()]) -> binary().
-spec rsa_sign(binary(), [binary()]) -> binary().
-spec rsa_sign(rsa_digest_type(), binary(), [binary()]) -> binary().

dss_sign(Data,Key) ->
    dss_sign(sha,Data,Key).
dss_sign(Type, Data, Key) ->
    case dss_sign_nif(Type,Data,Key) of
	error -> erlang:error(badkey, [Data, Key]);
	Sign -> Sign
    end.

dss_sign_nif(_Type,_Data,_Key) -> ?nif_stub.

%% Key = [E,N,D]  E=PublicExponent N=PublicModulus  D=PrivateExponent
rsa_sign(Data,Key) ->
    rsa_sign(sha, Data, Key).
rsa_sign(Type, Data, Key) ->
    case rsa_sign_nif(Type,Data,Key) of
	error -> erlang:error(badkey, [Type,Data,Key]);
	Sign -> Sign
    end.

rsa_sign_nif(_Type,_Data,_Key) -> ?nif_stub.


%%
%%  rsa_public_encrypt
%%  rsa_private_decrypt
-type rsa_padding() :: 'rsa_pkcs1_padding' | 'rsa_pkcs1_oaep_padding' | 'rsa_no_padding'.

-spec rsa_public_encrypt(binary(), [binary()], rsa_padding()) ->
				binary().
-spec rsa_public_decrypt(binary(), [binary()], rsa_padding()) ->
				binary().
-spec rsa_private_encrypt(binary(), [binary()], rsa_padding()) ->
				binary().
-spec rsa_private_decrypt(binary(), [binary()], rsa_padding()) ->
				binary().

%% Binary, Key = [E,N]
rsa_public_encrypt(BinMesg, Key, Padding) ->
    case rsa_public_crypt(BinMesg, Key, Padding, true) of
	error ->
	    erlang:error(encrypt_failed, [BinMesg,Key, Padding]);
	Sign -> Sign
    end.

rsa_public_crypt(_BinMsg, _Key, _Padding, _IsEncrypt) -> ?nif_stub.    

%% Binary, Key = [E,N,D]
rsa_private_decrypt(BinMesg, Key, Padding) ->
    case rsa_private_crypt(BinMesg, Key, Padding, false) of
	error ->
	    erlang:error(decrypt_failed, [BinMesg,Key, Padding]);
	Sign -> Sign
    end.

rsa_private_crypt(_BinMsg, _Key, _Padding, _IsEncrypt) -> ?nif_stub.    

    
%% Binary, Key = [E,N,D]
rsa_private_encrypt(BinMesg, Key, Padding) ->
    case rsa_private_crypt(BinMesg, Key, Padding, true) of
	error ->
	    erlang:error(encrypt_failed, [BinMesg,Key, Padding]);
	Sign -> Sign
    end.

%% Binary, Key = [E,N]
rsa_public_decrypt(BinMesg, Key, Padding) ->
    case rsa_public_crypt(BinMesg, Key, Padding, false) of
	error ->
	    erlang:error(decrypt_failed, [BinMesg,Key, Padding]);
	Sign -> Sign
    end.
    
%%
%% AES - with 128 or 256 bit key in cipher block chaining mode (CBC)
%%
-spec aes_cbc_128_encrypt(iodata(), binary(), iodata()) ->
				 binary().
-spec aes_cbc_128_decrypt(iodata(), binary(), iodata()) ->
				 binary().
-spec aes_cbc_256_encrypt(iodata(), binary(), iodata()) ->
				 binary().
-spec aes_cbc_256_decrypt(iodata(), binary(), iodata()) ->
				 binary().

aes_cbc_128_encrypt(Key, IVec, Data) ->
    aes_cbc_crypt(Key, IVec, Data, true).

aes_cbc_128_decrypt(Key, IVec, Data) ->
    aes_cbc_crypt(Key, IVec, Data, false).

aes_cbc_256_encrypt(Key, IVec, Data) ->
    aes_cbc_crypt(Key, IVec, Data, true).

aes_cbc_256_decrypt(Key, IVec, Data) ->
    aes_cbc_crypt(Key, IVec, Data, false).

aes_cbc_crypt(_Key, _IVec, _Data, _IsEncrypt) -> ?nif_stub.

%%
%% aes_cbc_ivec(Data) -> binary()
%%
%% Returns the IVec to be used in the next iteration of
%% aes_cbc_*_[encrypt|decrypt].
%% IVec size: 16 bytes
%%
aes_cbc_ivec(Data) when is_binary(Data) ->
    {_, IVec} = split_binary(Data, size(Data) - 16),
    IVec;
aes_cbc_ivec(Data) when is_list(Data) ->
    aes_cbc_ivec(list_to_binary(Data)).

%%
%% AES - in counter mode (CTR)
%%
-spec aes_ctr_encrypt(iodata(), binary(), iodata()) ->
				 binary().
-spec aes_ctr_decrypt(iodata(), binary(), iodata()) ->
				 binary().
 
aes_ctr_encrypt(_Key, _IVec, _Data) -> ?nif_stub.
aes_ctr_decrypt(_Key, _IVec, _Cipher) -> ?nif_stub.

%%
%% AES - in counter mode (CTR) with state maintained for multi-call streaming 
%%
-type ctr_state() :: { iodata(), binary(), binary(), integer() }.

-spec aes_ctr_stream_init(iodata(), binary()) -> ctr_state().
-spec aes_ctr_stream_encrypt(ctr_state(), binary()) ->
				 { ctr_state(), binary() }.
-spec aes_ctr_stream_decrypt(ctr_state(), binary()) ->
				 { ctr_state(), binary() }.
 
aes_ctr_stream_init(Key, IVec) -> 
    {Key, IVec, << 0:128 >>, 0}.
aes_ctr_stream_encrypt({_Key, _IVec, _ECount, _Num}=_State, _Data) -> ?nif_stub.
aes_ctr_stream_decrypt({_Key, _IVec, _ECount, _Num}=_State, _Cipher) -> ?nif_stub.
     
%%
%% XOR - xor to iolists and return a binary
%% NB doesn't check that they are the same size, just concatenates
%% them and sends them to the driver
%%
-spec exor(iodata(), iodata()) -> binary().

exor(_A, _B) -> ?nif_stub.

%%
%% RC4 - symmetric stream cipher
%%
-spec rc4_encrypt(iodata(), iodata()) -> binary().

rc4_encrypt(_Key, _Data) -> ?nif_stub.
rc4_set_key(_Key) -> ?nif_stub.
rc4_encrypt_with_state(_State, _Data) -> ?nif_stub.

%%
%% RC2 - 40 bits block cipher
%%
rc2_40_cbc_encrypt(Key, IVec, Data) ->
    rc2_40_cbc_crypt(Key,IVec,Data,true).

rc2_40_cbc_decrypt(Key, IVec, Data) ->
    rc2_40_cbc_crypt(Key,IVec,Data,false).

rc2_40_cbc_crypt(_Key, _IVec, _Data, _IsEncrypt) -> ?nif_stub.    

%%
%% DH Diffie-Hellman functions
%% 

%% Generate (and check) Parameters is not documented because they are implemented
%% for testing (and offline parameter generation) only.
%% From the openssl doc: 
%%  DH_generate_parameters() may run for several hours before finding a suitable prime.
%% Thus dh_generate_parameters may in this implementation block 
%% the emulator for several hours.
%%
%% usage: dh_generate_parameters(1024, 2 or 5) -> 
%%    [Prime=mpint(), SharedGenerator=mpint()]
dh_generate_parameters(PrimeLen, Generator) ->
    case dh_generate_parameters_nif(PrimeLen, Generator) of
	error -> erlang:error(generation_failed, [PrimeLen,Generator]);
	Ret -> Ret
    end.  

dh_generate_parameters_nif(_PrimeLen, _Generator) -> ?nif_stub.

%% Checks that the DHParameters are ok.
%% DHParameters = [P (Prime)= mpint(), G(Generator) = mpint()]
dh_check([_Prime,_Gen]) -> ?nif_stub.

%% DHParameters = [P (Prime)= mpint(), G(Generator) = mpint()]
%% PrivKey = mpint()
-spec dh_generate_key([binary()]) -> {binary(),binary()}.
-spec dh_generate_key(binary()|undefined, [binary()]) ->
			     {binary(),binary()}.

dh_generate_key(DHParameters) ->
    dh_generate_key(undefined, DHParameters).
dh_generate_key(PrivateKey, DHParameters) ->
    case dh_generate_key_nif(PrivateKey, DHParameters) of
	error -> erlang:error(generation_failed, [PrivateKey,DHParameters]);
	Res -> Res
    end.

dh_generate_key_nif(_PrivateKey, _DHParameters) -> ?nif_stub.

%% DHParameters = [P (Prime)= mpint(), G(Generator) = mpint()]
%% MyPrivKey, OthersPublicKey = mpint() 
-spec dh_compute_key(binary(), binary(), [binary()]) -> binary().

dh_compute_key(OthersPublicKey, MyPrivateKey, DHParameters) ->
    case dh_compute_key_nif(OthersPublicKey,MyPrivateKey,DHParameters) of
	error -> erlang:error(computation_failed, [OthersPublicKey,MyPrivateKey,DHParameters]);
	Ret -> Ret
    end.

dh_compute_key_nif(_OthersPublicKey, _MyPrivateKey, _DHParameters) -> ?nif_stub.

%%
%%  LOCAL FUNCTIONS
%%


%% large integer in a binary with 32bit length
%% MP representaion  (SSH2)
mpint(X) when X < 0 ->
    case X of
	-1 ->
	    <<0,0,0,1,16#ff>>;	    
       _ ->
	    mpint_neg(X,0,[])
    end;
mpint(X) ->
    case X of 
	0 ->
	    <<0,0,0,0>>;
	_ ->
	    mpint_pos(X,0,[])
    end.

-define(UINT32(X),   X:32/unsigned-big-integer).

mpint_neg(-1,I,Ds=[MSB|_]) ->
    if MSB band 16#80 =/= 16#80 ->
	    <<?UINT32((I+1)), (list_to_binary([255|Ds]))/binary>>;
       true ->
	    (<<?UINT32(I), (list_to_binary(Ds))/binary>>)
    end;
mpint_neg(X,I,Ds)  ->
    mpint_neg(X bsr 8,I+1,[(X band 255)|Ds]).
    
mpint_pos(0,I,Ds=[MSB|_]) ->
    if MSB band 16#80 == 16#80 ->
	    <<?UINT32((I+1)), (list_to_binary([0|Ds]))/binary>>;
       true ->
	    (<<?UINT32(I), (list_to_binary(Ds))/binary>>)
    end;
mpint_pos(X,I,Ds) ->
    mpint_pos(X bsr 8,I+1,[(X band 255)|Ds]).

%% int from integer in a binary with 32bit length
erlint(<<MPIntSize:32/integer,MPIntValue/binary>>) ->
    Bits= MPIntSize * 8,
    <<Integer:Bits/integer>> = MPIntValue,
    Integer.