1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3 *
4 * LibTomCrypt is a library that provides various cryptographic
5 * algorithms in a highly modular and flexible manner.
6 *
7 * The library is free for all purposes without any express
8 * guarantee it works.
9 */
10 #include "tomcrypt_private.h"
11
12 /**
13 @file f8_encrypt.c
14 F8 implementation, encrypt data, Tom St Denis
15 */
16
17 #ifdef LTC_F8_MODE
18
19 /**
20 F8 encrypt
21 @param pt Plaintext
22 @param ct [out] Ciphertext
23 @param len Length of plaintext (octets)
24 @param f8 F8 state
25 @return CRYPT_OK if successful
26 */
f8_encrypt(const unsigned char * pt,unsigned char * ct,unsigned long len,symmetric_F8 * f8)27 int f8_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_F8 *f8)
28 {
29 int err, x;
30 unsigned char buf[MAXBLOCKSIZE];
31 LTC_ARGCHK(pt != NULL);
32 LTC_ARGCHK(ct != NULL);
33 LTC_ARGCHK(f8 != NULL);
34 if ((err = cipher_is_valid(f8->cipher)) != CRYPT_OK) {
35 return err;
36 }
37
38 /* is blocklen/padlen valid? */
39 if (f8->blocklen < 0 || f8->blocklen > (int)sizeof(f8->IV) ||
40 f8->padlen < 0 || f8->padlen > (int)sizeof(f8->IV)) {
41 return CRYPT_INVALID_ARG;
42 }
43
44 zeromem(buf, sizeof(buf));
45
46 /* make sure the pad is empty */
47 if (f8->padlen == f8->blocklen) {
48 /* xor of IV, MIV and blockcnt == what goes into cipher */
49 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
50 ++(f8->blockcnt);
51 for (x = 0; x < f8->blocklen; x++) {
52 f8->IV[x] ^= f8->MIV[x] ^ buf[x];
53 }
54 if ((err = cipher_descriptor[f8->cipher]->ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
55 return err;
56 }
57 f8->padlen = 0;
58 }
59
60 #ifdef LTC_FAST
61 if (f8->padlen == 0) {
62 while (len >= (unsigned long)f8->blocklen) {
63 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
64 ++(f8->blockcnt);
65 for (x = 0; x < f8->blocklen; x += sizeof(LTC_FAST_TYPE)) {
66 *(LTC_FAST_TYPE_PTR_CAST(&ct[x])) = *(LTC_FAST_TYPE_PTR_CAST(&pt[x])) ^ *(LTC_FAST_TYPE_PTR_CAST(&f8->IV[x]));
67 *(LTC_FAST_TYPE_PTR_CAST(&f8->IV[x])) ^= *(LTC_FAST_TYPE_PTR_CAST(&f8->MIV[x])) ^ *(LTC_FAST_TYPE_PTR_CAST(&buf[x]));
68 }
69 if ((err = cipher_descriptor[f8->cipher]->ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
70 return err;
71 }
72 len -= x;
73 pt += x;
74 ct += x;
75 }
76 }
77 #endif
78
79 while (len > 0) {
80 if (f8->padlen == f8->blocklen) {
81 /* xor of IV, MIV and blockcnt == what goes into cipher */
82 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
83 ++(f8->blockcnt);
84 for (x = 0; x < f8->blocklen; x++) {
85 f8->IV[x] ^= f8->MIV[x] ^ buf[x];
86 }
87 if ((err = cipher_descriptor[f8->cipher]->ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
88 return err;
89 }
90 f8->padlen = 0;
91 }
92 *ct++ = *pt++ ^ f8->IV[f8->padlen++];
93 --len;
94 }
95 return CRYPT_OK;
96 }
97
98 #endif
99
100 /* ref: $Format:%D$ */
101 /* git commit: $Format:%H$ */
102 /* commit time: $Format:%ai$ */
103