1/*
2 * ccpad.h
3 * corecrypto
4 *
5 * Created on 12/07/2010
6 *
7 * Copyright (c) 2010,2011,2012,2014,2015 Apple Inc. All rights reserved.
8 *
9 */
10
11#ifndef _CORECRYPTO_CCPAD_H_
12#define _CORECRYPTO_CCPAD_H_
13
14#include <corecrypto/ccmode.h>
15
16// CTS1,2,3 are defined in Addendum to 800-38A,
17// "Cipher Modes of Operation: Three Variants of Ciphertext Stealing for CBC Mode"
18// CTS3 is also known as "CTS" in RFC3962
19
20/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
21size_t ccpad_cts1_decrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
22 size_t nbytes, const void *in, void *out);
23
24/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
25size_t ccpad_cts1_encrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
26 size_t nbytes, const void *in, void *out);
27/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
28size_t ccpad_cts2_decrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
29 size_t nbytes, const void *in, void *out);
30
31/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
32size_t ccpad_cts2_encrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
33 size_t nbytes, const void *in, void *out);
34/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
35size_t ccpad_cts3_decrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
36 size_t nbytes, const void *in, void *out);
37
38/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
39size_t ccpad_cts3_encrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
40 size_t nbytes, const void *in, void *out);
41
42/* Contract is nbytes is non zero and a multiple of block_size. Furthermore in is nbytes long and out is nbytes long. Returns number of bytes written to out (technically we always write nbytes to out but the returned value is the number of bytes decrypted after removal of padding.
43
44 To be safe we remove the entire offending block if the pkcs7 padding checks failed. However we purposely don't report the failure to decode the padding since any use of this error leads to potential security exploits. So currently there is no way to distinguish between a full block of padding and bad padding.
45 */
46size_t ccpad_pkcs7_decrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
47 size_t nbytes, const void *in, void *out);
48
49/* Contract is in is nbytes long. Writes (nbytes / block_size) + 1 times block_size to out. In other words, out must be nbytes rounded down to the closest multiple of block_size plus block_size bytes. */
50size_t ccpad_pkcs7_encrypt(const struct ccmode_cbc *cbc, cccbc_ctx *ctx, cccbc_iv *iv,
51 size_t nbytes, const void *in, void *out);
52
53/* Contract is 'don't break CommonCrypto functionality that allows PKCS7 padding with ECB mode'. This is basically the same routines above, without an IV, because calling
54 crypt with an IV makes ecb cry (and crash) */
55
56size_t ccpad_pkcs7_ecb_decrypt(const struct ccmode_ecb *ecb, ccecb_ctx *ecb_key,
57 size_t nbytes, const void *in, void *out);
58
59size_t ccpad_pkcs7_ecb_encrypt(const struct ccmode_ecb *ecb, ccecb_ctx *ctx,
60 size_t nbytes, const void *in, void *out);
61
62/* Function common to ccpad_pkcs7_ecb_decrypt and ccpad_pkcs7_decrypt */
63size_t ccpad_pkcs7_decode(const size_t block_size, const uint8_t* last_block);
64
65/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
66size_t ccpad_xts_decrypt(const struct ccmode_xts *xts, ccxts_ctx *ctx, ccxts_tweak *tweak,
67 size_t nbytes, const void *in, void *out);
68
69/* Contract is nbytes is at least 1 block + 1 byte. Also in is nbytes long out is nbytes long. */
70void ccpad_xts_encrypt(const struct ccmode_xts *xts, ccxts_ctx *ctx, ccxts_tweak *tweak,
71 size_t nbytes, const void *in, void *out);
72
73#endif /* _CORECRYPTO_CCPAD_H_ */
74