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comparison libtomcrypt/src/encauth/gcm/gcm_add_iv.c @ 1471:6dba84798cd5

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Update to libtomcrypt 1.18.1, merged with Dropbear changes
author Matt Johnston <matt@ucc.asn.au>
date Fri, 09 Feb 2018 21:44:05 +0800
parents f849a5ca2efc
children
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1470:8bba51a55704 1471:6dba84798cd5
3 * LibTomCrypt is a library that provides various cryptographic 3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner. 4 * algorithms in a highly modular and flexible manner.
5 * 5 *
6 * The library is free for all purposes without any express 6 * The library is free for all purposes without any express
7 * guarantee it works. 7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtom.org
10 */ 8 */
11 9
12 /** 10 /**
13 @file gcm_add_iv.c 11 @file gcm_add_iv.c
14 GCM implementation, add IV data to the state, by Tom St Denis 12 GCM implementation, add IV data to the state, by Tom St Denis
22 @param gcm The GCM state 20 @param gcm The GCM state
23 @param IV The initial value data to add 21 @param IV The initial value data to add
24 @param IVlen The length of the IV 22 @param IVlen The length of the IV
25 @return CRYPT_OK on success 23 @return CRYPT_OK on success
26 */ 24 */
27 int gcm_add_iv(gcm_state *gcm, 25 int gcm_add_iv(gcm_state *gcm,
28 const unsigned char *IV, unsigned long IVlen) 26 const unsigned char *IV, unsigned long IVlen)
29 { 27 {
30 unsigned long x, y; 28 unsigned long x, y;
31 int err; 29 int err;
32 30
37 35
38 /* must be in IV mode */ 36 /* must be in IV mode */
39 if (gcm->mode != LTC_GCM_MODE_IV) { 37 if (gcm->mode != LTC_GCM_MODE_IV) {
40 return CRYPT_INVALID_ARG; 38 return CRYPT_INVALID_ARG;
41 } 39 }
42 40
43 if (gcm->buflen >= 16 || gcm->buflen < 0) { 41 if (gcm->buflen >= 16 || gcm->buflen < 0) {
44 return CRYPT_INVALID_ARG; 42 return CRYPT_INVALID_ARG;
45 } 43 }
46 44
47 if ((err = cipher_is_valid(gcm->cipher)) != CRYPT_OK) { 45 if ((err = cipher_is_valid(gcm->cipher)) != CRYPT_OK) {
57 x = 0; 55 x = 0;
58 #ifdef LTC_FAST 56 #ifdef LTC_FAST
59 if (gcm->buflen == 0) { 57 if (gcm->buflen == 0) {
60 for (x = 0; x < (IVlen & ~15); x += 16) { 58 for (x = 0; x < (IVlen & ~15); x += 16) {
61 for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) { 59 for (y = 0; y < 16; y += sizeof(LTC_FAST_TYPE)) {
62 *((LTC_FAST_TYPE*)(&gcm->X[y])) ^= *((LTC_FAST_TYPE*)(&IV[x + y])); 60 *(LTC_FAST_TYPE_PTR_CAST(&gcm->X[y])) ^= *(LTC_FAST_TYPE_PTR_CAST(&IV[x + y]));
63 } 61 }
64 gcm_mult_h(gcm, gcm->X); 62 gcm_mult_h(gcm, gcm->X);
65 gcm->totlen += 128; 63 gcm->totlen += 128;
66 } 64 }
67 IV += x; 65 IV += x;
70 68
71 /* start adding IV data to the state */ 69 /* start adding IV data to the state */
72 for (; x < IVlen; x++) { 70 for (; x < IVlen; x++) {
73 gcm->buf[gcm->buflen++] = *IV++; 71 gcm->buf[gcm->buflen++] = *IV++;
74 72
75 if (gcm->buflen == 16) { 73 if (gcm->buflen == 16) {
76 /* GF mult it */ 74 /* GF mult it */
77 for (y = 0; y < 16; y++) { 75 for (y = 0; y < 16; y++) {
78 gcm->X[y] ^= gcm->buf[y]; 76 gcm->X[y] ^= gcm->buf[y];
79 } 77 }
80 gcm_mult_h(gcm, gcm->X); 78 gcm_mult_h(gcm, gcm->X);
85 83
86 return CRYPT_OK; 84 return CRYPT_OK;
87 } 85 }
88 86
89 #endif 87 #endif
90
91 88
92 /* $Source$ */ 89
93 /* $Revision$ */ 90 /* ref: $Format:%D$ */
94 /* $Date$ */ 91 /* git commit: $Format:%H$ */
92 /* commit time: $Format:%ai$ */