]> git.cryptolib.org Git - arm-crypto-lib.git/blob - present/present128.c
fixing bugs reported by Christian Dernehl
[arm-crypto-lib.git] / present / present128.c
1 /* present128.c */
2 /*
3     This file is part of the AVR-Crypto-Lib.
4     Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
5
6     This program is free software: you can redistribute it and/or modify
7     it under the terms of the GNU General Public License as published by
8     the Free Software Foundation, either version 3 of the License, or
9     (at your option) any later version.
10
11     This program is distributed in the hope that it will be useful,
12     but WITHOUT ANY WARRANTY; without even the implied warranty of
13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14     GNU General Public License for more details.
15
16     You should have received a copy of the GNU General Public License
17     along with this program.  If not, see <http://www.gnu.org/licenses/>.
18 */
19 /**
20  * present128.c
21  * a implementation of the PRESENT block-cipher
22  * author: Daniel Otte
23  * email:  daniel.otte@rub.de
24  * license: GPLv3
25  * 
26  * */
27  
28 #include <string.h>
29 #include <stdint.h> 
30 #include "memxor.h"
31 #include "present_common.h"
32 #include "present128.h"
33
34 static
35 void key_update_128(uint8_t* buffer, uint8_t round){
36         uint8_t j;
37         uint8_t t8;
38         union __attribute__((packed)){
39                 uint8_t   v8[2];
40                 uint16_t v16;
41         } tmp;
42         /* rotate buffer 67 right */
43         for(j=0; j<8; ++j){
44                 tmp.v8[0] = buffer[j];
45                 buffer[j] = buffer[j + 8];
46                 buffer[j + 8] = tmp.v8[0];
47         }
48         j=0;
49         t8 = (uint16_t)buffer[15] << (5);
50         do{
51                 tmp.v8[1] = buffer[j];
52                 tmp.v16 >>= 3;
53                 buffer[j] = tmp.v8[1] | t8;
54                 t8 = tmp.v8[0] & 0xe0;
55         }while(++j<16);
56         /* rotating done now substitution */
57         buffer[0] = present_sbox(buffer[0]);
58         /* xor with round counter */
59         buffer[8] ^= round << 6;
60         buffer[7] ^= round >> 2;
61 }
62
63
64 static
65 void key_update_128_inv(uint8_t* buffer, uint8_t round){
66         uint8_t j;
67         uint8_t t8;
68         union __attribute__((packed)){
69                 uint8_t   v8[2];
70                 uint16_t v16;
71         } tmp;
72         /* xor with round counter */
73         buffer[8] ^= round << 6;
74         buffer[7] ^= round >> 2;
75
76         /* rotating done now substitution */
77         buffer[0] = present_sbox_inv(buffer[0]);
78
79         /* rotate buffer 67 left */
80         for(j=0; j<8; ++j){
81                 tmp.v8[0] = buffer[j];
82                 buffer[j] = buffer[j + 8];
83                 buffer[j + 8] = tmp.v8[0];
84         }
85         j=15;
86         t8 = (uint16_t)buffer[0] >> (5);
87         do{
88                 tmp.v8[0] = buffer[j];
89                 tmp.v16 <<= 3;
90                 buffer[j] = tmp.v8[0] | t8;
91                 t8 = tmp.v8[1] & 0x07;
92         }while(j--);
93 }
94
95 void present128_init(const uint8_t* key, uint8_t keysize_b, present128_ctx_t* ctx){
96         uint8_t i;
97         memcpy(ctx->fwd_key, key, 16);
98         memcpy(ctx->rev_key, key, 16);
99         for(i=1; i<32; ++i){
100                 key_update_128(ctx->rev_key, i);
101         }
102 }
103
104 void present128_enc(void* buffer, present128_ctx_t* ctx){
105         present_generic_enc(buffer, (uint8_t*)ctx, 16, key_update_128);
106 }
107
108 void present128_dec(void* buffer, present128_ctx_t* ctx){
109         present_generic_dec(buffer, (uint8_t*)ctx, 16, key_update_128_inv);
110 }
111
112 /*
113 void present128_enc(void* buffer, present128_ctx_t* ctx){
114         uint8_t i,j,tmp[8], k[16];
115         memcpy(k, ctx->fwd_key, 16);
116         memxor(buffer, k, 8);
117         for(i=1; i<32; ++i){
118                 j = 7;
119                 do{
120                         tmp[j] = present_sbox(((uint8_t*)buffer)[j]);
121                 }while(j--);
122                 present_p(buffer, tmp);
123                 key_update_128(k, i);
124                 memxor(buffer, k, 8);
125         }
126 }
127
128 void present128_dec(void* buffer, present128_ctx_t* ctx){
129         uint8_t j,tmp[8], k[16];
130         uint8_t i;
131         memcpy(k, ctx->rev_key, 16);
132         memxor(buffer, k, 8);
133         i = 31;
134         do{
135                 present_p(tmp, buffer);
136                 present_p(buffer, tmp);
137                 j = 7;
138                 do{
139                         ((uint8_t*)buffer)[j] = present_sbox_inv(((uint8_t*)buffer)[j]);
140                 }while(j--);
141                 key_update_128_inv(k, i);
142                 memxor(buffer, k, 8);
143         }while(--i);
144 }
145 */