1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis */
2 /* SPDX-License-Identifier: Unlicense */
3 #include "tomcrypt_private.h"
4
5 /**
6 @file f8_encrypt.c
7 F8 implementation, encrypt data, Tom St Denis
8 */
9
10 #ifdef LTC_F8_MODE
11
12 /**
13 F8 encrypt
14 @param pt Plaintext
15 @param ct [out] Ciphertext
16 @param len Length of plaintext (octets)
17 @param f8 F8 state
18 @return CRYPT_OK if successful
19 */
f8_encrypt(const unsigned char * pt,unsigned char * ct,unsigned long len,symmetric_F8 * f8)20 int f8_encrypt(const unsigned char *pt, unsigned char *ct, unsigned long len, symmetric_F8 *f8)
21 {
22 int err, x;
23 unsigned char buf[MAXBLOCKSIZE];
24 LTC_ARGCHK(pt != NULL);
25 LTC_ARGCHK(ct != NULL);
26 LTC_ARGCHK(f8 != NULL);
27 if ((err = cipher_is_valid(f8->cipher)) != CRYPT_OK) {
28 return err;
29 }
30
31 /* is blocklen/padlen valid? */
32 if (f8->blocklen < 0 || f8->blocklen > (int)sizeof(f8->IV) ||
33 f8->padlen < 0 || f8->padlen > (int)sizeof(f8->IV)) {
34 return CRYPT_INVALID_ARG;
35 }
36
37 zeromem(buf, sizeof(buf));
38
39 /* make sure the pad is empty */
40 if (f8->padlen == f8->blocklen) {
41 /* xor of IV, MIV and blockcnt == what goes into cipher */
42 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
43 ++(f8->blockcnt);
44 for (x = 0; x < f8->blocklen; x++) {
45 f8->IV[x] ^= f8->MIV[x] ^ buf[x];
46 }
47 if ((err = cipher_descriptor[f8->cipher]->ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
48 return err;
49 }
50 f8->padlen = 0;
51 }
52
53 #ifdef LTC_FAST
54 if (f8->padlen == 0) {
55 while (len >= (unsigned long)f8->blocklen) {
56 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
57 ++(f8->blockcnt);
58 for (x = 0; x < f8->blocklen; x += sizeof(LTC_FAST_TYPE)) {
59 *(LTC_FAST_TYPE_PTR_CAST(&ct[x])) = *(LTC_FAST_TYPE_PTR_CAST(&pt[x])) ^ *(LTC_FAST_TYPE_PTR_CAST(&f8->IV[x]));
60 *(LTC_FAST_TYPE_PTR_CAST(&f8->IV[x])) ^= *(LTC_FAST_TYPE_PTR_CAST(&f8->MIV[x])) ^ *(LTC_FAST_TYPE_PTR_CAST(&buf[x]));
61 }
62 if ((err = cipher_descriptor[f8->cipher]->ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
63 return err;
64 }
65 len -= x;
66 pt += x;
67 ct += x;
68 }
69 }
70 #endif
71
72 while (len > 0) {
73 if (f8->padlen == f8->blocklen) {
74 /* xor of IV, MIV and blockcnt == what goes into cipher */
75 STORE32H(f8->blockcnt, (buf+(f8->blocklen-4)));
76 ++(f8->blockcnt);
77 for (x = 0; x < f8->blocklen; x++) {
78 f8->IV[x] ^= f8->MIV[x] ^ buf[x];
79 }
80 if ((err = cipher_descriptor[f8->cipher]->ecb_encrypt(f8->IV, f8->IV, &f8->key)) != CRYPT_OK) {
81 return err;
82 }
83 f8->padlen = 0;
84 }
85 *ct++ = *pt++ ^ f8->IV[f8->padlen++];
86 --len;
87 }
88 return CRYPT_OK;
89 }
90
91 #endif
92