1 /**********************************************************************
2 * gosthash.c *
3 * Copyright (c) 2005-2006 Cryptocom LTD *
4 * This file is distributed under the same license as OpenSSL *
5 * *
6 * Implementation of GOST R 34.11-94 hash function *
7 * uses on gost89.c and gost89.h Doesn't need OpenSSL *
8 **********************************************************************/
9 #include <string.h>
10
11 #include "gost89.h"
12 #include "gosthash.h"
13
14 /*
15 * Use OPENSSL_malloc for memory allocation if compiled with
16 * -DOPENSSL_BUILD, and libc malloc otherwise
17 */
18 #ifndef MYALLOC
19 # ifdef OPENSSL_BUILD
20 # include <openssl/crypto.h>
21 # define MYALLOC(size) OPENSSL_malloc(size)
22 # define MYFREE(ptr) OPENSSL_free(ptr)
23 # else
24 # define MYALLOC(size) malloc(size)
25 # define MYFREE(ptr) free(ptr)
26 # endif
27 #endif
28 /*
29 * Following functions are various bit meshing routines used in GOST R
30 * 34.11-94 algorithms
31 */
swap_bytes(byte * w,byte * k)32 static void swap_bytes(byte * w, byte * k)
33 {
34 int i, j;
35 for (i = 0; i < 4; i++)
36 for (j = 0; j < 8; j++)
37 k[i + 4 * j] = w[8 * i + j];
38
39 }
40
41 /* was A_A */
circle_xor8(const byte * w,byte * k)42 static void circle_xor8(const byte * w, byte * k)
43 {
44 byte buf[8];
45 int i;
46 memcpy(buf, w, 8);
47 memmove(k, w + 8, 24);
48 for (i = 0; i < 8; i++)
49 k[i + 24] = buf[i] ^ k[i];
50 }
51
52 /* was R_R */
transform_3(byte * data)53 static void transform_3(byte * data)
54 {
55 unsigned short int acc;
56 acc = (data[0] ^ data[2] ^ data[4] ^ data[6] ^ data[24] ^ data[30]) |
57 ((data[1] ^ data[3] ^ data[5] ^ data[7] ^ data[25] ^ data[31]) << 8);
58 memmove(data, data + 2, 30);
59 data[30] = acc & 0xff;
60 data[31] = acc >> 8;
61 }
62
63 /* Adds blocks of N bytes modulo 2**(8*n). Returns carry*/
add_blocks(int n,byte * left,const byte * right)64 static int add_blocks(int n, byte * left, const byte * right)
65 {
66 int i;
67 int carry = 0;
68 int sum;
69 for (i = 0; i < n; i++) {
70 sum = (int)left[i] + (int)right[i] + carry;
71 left[i] = sum & 0xff;
72 carry = sum >> 8;
73 }
74 return carry;
75 }
76
77 /* Xor two sequences of bytes */
xor_blocks(byte * result,const byte * a,const byte * b,size_t len)78 static void xor_blocks(byte * result, const byte * a, const byte * b,
79 size_t len)
80 {
81 size_t i;
82 for (i = 0; i < len; i++)
83 result[i] = a[i] ^ b[i];
84 }
85
86 /*
87 * Calculate H(i+1) = Hash(Hi,Mi)
88 * Where H and M are 32 bytes long
89 */
hash_step(gost_ctx * c,byte * H,const byte * M)90 static int hash_step(gost_ctx * c, byte * H, const byte * M)
91 {
92 byte U[32], W[32], V[32], S[32], Key[32];
93 int i;
94 /* Compute first key */
95 xor_blocks(W, H, M, 32);
96 swap_bytes(W, Key);
97 /* Encrypt first 8 bytes of H with first key */
98 gost_enc_with_key(c, Key, H, S);
99 /* Compute second key */
100 circle_xor8(H, U);
101 circle_xor8(M, V);
102 circle_xor8(V, V);
103 xor_blocks(W, U, V, 32);
104 swap_bytes(W, Key);
105 /* encrypt second 8 bytes of H with second key */
106 gost_enc_with_key(c, Key, H + 8, S + 8);
107 /* compute third key */
108 circle_xor8(U, U);
109 U[31] = ~U[31];
110 U[29] = ~U[29];
111 U[28] = ~U[28];
112 U[24] = ~U[24];
113 U[23] = ~U[23];
114 U[20] = ~U[20];
115 U[18] = ~U[18];
116 U[17] = ~U[17];
117 U[14] = ~U[14];
118 U[12] = ~U[12];
119 U[10] = ~U[10];
120 U[8] = ~U[8];
121 U[7] = ~U[7];
122 U[5] = ~U[5];
123 U[3] = ~U[3];
124 U[1] = ~U[1];
125 circle_xor8(V, V);
126 circle_xor8(V, V);
127 xor_blocks(W, U, V, 32);
128 swap_bytes(W, Key);
129 /* encrypt third 8 bytes of H with third key */
130 gost_enc_with_key(c, Key, H + 16, S + 16);
131 /* Compute fourth key */
132 circle_xor8(U, U);
133 circle_xor8(V, V);
134 circle_xor8(V, V);
135 xor_blocks(W, U, V, 32);
136 swap_bytes(W, Key);
137 /* Encrypt last 8 bytes with fourth key */
138 gost_enc_with_key(c, Key, H + 24, S + 24);
139 for (i = 0; i < 12; i++)
140 transform_3(S);
141 xor_blocks(S, S, M, 32);
142 transform_3(S);
143 xor_blocks(S, S, H, 32);
144 for (i = 0; i < 61; i++)
145 transform_3(S);
146 memcpy(H, S, 32);
147 return 1;
148 }
149
150 /*
151 * Initialize gost_hash ctx - cleans up temporary structures and set up
152 * substitution blocks
153 */
init_gost_hash_ctx(gost_hash_ctx * ctx,const gost_subst_block * subst_block)154 int init_gost_hash_ctx(gost_hash_ctx * ctx,
155 const gost_subst_block * subst_block)
156 {
157 memset(ctx, 0, sizeof(gost_hash_ctx));
158 ctx->cipher_ctx = (gost_ctx *) MYALLOC(sizeof(gost_ctx));
159 if (!ctx->cipher_ctx) {
160 return 0;
161 }
162 gost_init(ctx->cipher_ctx, subst_block);
163 return 1;
164 }
165
166 /*
167 * Free cipher CTX if it is dynamically allocated. Do not use
168 * if cipher ctx is statically allocated as in OpenSSL implementation of
169 * GOST hash algroritm
170 *
171 */
done_gost_hash_ctx(gost_hash_ctx * ctx)172 void done_gost_hash_ctx(gost_hash_ctx * ctx)
173 {
174 /*
175 * No need to use gost_destroy, because cipher keys are not really secret
176 * when hashing
177 */
178 MYFREE(ctx->cipher_ctx);
179 }
180
181 /*
182 * reset state of hash context to begin hashing new message
183 */
start_hash(gost_hash_ctx * ctx)184 int start_hash(gost_hash_ctx * ctx)
185 {
186 if (!ctx->cipher_ctx)
187 return 0;
188 memset(&(ctx->H), 0, 32);
189 memset(&(ctx->S), 0, 32);
190 ctx->len = 0L;
191 ctx->left = 0;
192 return 1;
193 }
194
195 /*
196 * Hash block of arbitrary length
197 *
198 *
199 */
hash_block(gost_hash_ctx * ctx,const byte * block,size_t length)200 int hash_block(gost_hash_ctx * ctx, const byte * block, size_t length)
201 {
202 if (ctx->left) {
203 /*
204 * There are some bytes from previous step
205 */
206 unsigned int add_bytes = 32 - ctx->left;
207 if (add_bytes > length) {
208 add_bytes = length;
209 }
210 memcpy(&(ctx->remainder[ctx->left]), block, add_bytes);
211 ctx->left += add_bytes;
212 if (ctx->left < 32) {
213 return 1;
214 }
215 block += add_bytes;
216 length -= add_bytes;
217 hash_step(ctx->cipher_ctx, ctx->H, ctx->remainder);
218 add_blocks(32, ctx->S, ctx->remainder);
219 ctx->len += 32;
220 ctx->left = 0;
221 }
222 while (length >= 32) {
223 hash_step(ctx->cipher_ctx, ctx->H, block);
224
225 add_blocks(32, ctx->S, block);
226 ctx->len += 32;
227 block += 32;
228 length -= 32;
229 }
230 if (length) {
231 memcpy(ctx->remainder, block, ctx->left = length);
232 }
233 return 1;
234 }
235
236 /*
237 * Compute hash value from current state of ctx
238 * state of hash ctx becomes invalid and cannot be used for further
239 * hashing.
240 */
finish_hash(gost_hash_ctx * ctx,byte * hashval)241 int finish_hash(gost_hash_ctx * ctx, byte * hashval)
242 {
243 byte buf[32];
244 byte H[32];
245 byte S[32];
246 ghosthash_len fin_len = ctx->len;
247 byte *bptr;
248 memcpy(H, ctx->H, 32);
249 memcpy(S, ctx->S, 32);
250 if (ctx->left) {
251 memset(buf, 0, 32);
252 memcpy(buf, ctx->remainder, ctx->left);
253 hash_step(ctx->cipher_ctx, H, buf);
254 add_blocks(32, S, buf);
255 fin_len += ctx->left;
256 }
257 memset(buf, 0, 32);
258 bptr = buf;
259 fin_len <<= 3; /* Hash length in BITS!! */
260 while (fin_len > 0) {
261 *(bptr++) = (byte) (fin_len & 0xFF);
262 fin_len >>= 8;
263 };
264 hash_step(ctx->cipher_ctx, H, buf);
265 hash_step(ctx->cipher_ctx, H, S);
266 memcpy(hashval, H, 32);
267 return 1;
268 }
269