2 * Copyright (c) 2010 Werner Dittmann
4 * Permission is hereby granted, free of charge, to any person
5 * obtaining a copy of this software and associated documentation
6 * files (the "Software"), to deal in the Software without
7 * restriction, including without limitation the rights to use,
8 * copy, modify, merge, publish, distribute, sublicense, and/or sell
9 * copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following
13 * The above copyright notice and this permission notice shall be
14 * included in all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
18 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
20 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
21 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
22 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
23 * OTHER DEALINGS IN THE SOFTWARE.
26 #include <linux/string.h>
27 #include "skein_api.h"
29 int skein_ctx_prepare(struct skein_ctx *ctx, enum skein_size size)
31 skein_assert_ret(ctx && size, SKEIN_FAIL);
33 memset(ctx, 0, sizeof(struct skein_ctx));
34 ctx->skein_size = size;
39 int skein_init(struct skein_ctx *ctx, size_t hash_bit_len)
44 u64 tree_info = SKEIN_CFG_TREE_INFO_SEQUENTIAL;
46 skein_assert_ret(ctx, SKEIN_FAIL);
48 * The following two lines rely of the fact that the real Skein
49 * contexts are a union in out context and thus have tha maximum
50 * memory available. The beauty of C :-) .
53 x_len = ctx->skein_size / 8;
55 * If size is the same and hash bit length is zero then reuse
56 * the save chaining variables.
58 switch (ctx->skein_size) {
60 ret = skein_256_init_ext(&ctx->m.s256, hash_bit_len,
64 ret = skein_512_init_ext(&ctx->m.s512, hash_bit_len,
68 ret = skein_1024_init_ext(&ctx->m.s1024, hash_bit_len,
73 if (ret == SKEIN_SUCCESS) {
75 * Save chaining variables for this combination of size and
78 memcpy(ctx->x_save, x, x_len);
83 int skein_mac_init(struct skein_ctx *ctx, const u8 *key, size_t key_len,
89 u64 tree_info = SKEIN_CFG_TREE_INFO_SEQUENTIAL;
91 skein_assert_ret(ctx, SKEIN_FAIL);
94 x_len = ctx->skein_size / 8;
96 skein_assert_ret(hash_bit_len, SKEIN_BAD_HASHLEN);
98 switch (ctx->skein_size) {
100 ret = skein_256_init_ext(&ctx->m.s256, hash_bit_len,
101 tree_info, key, key_len);
105 ret = skein_512_init_ext(&ctx->m.s512, hash_bit_len,
106 tree_info, key, key_len);
109 ret = skein_1024_init_ext(&ctx->m.s1024, hash_bit_len,
110 tree_info, key, key_len);
114 if (ret == SKEIN_SUCCESS) {
116 * Save chaining variables for this combination of key,
117 * key_len, hash_bit_len
119 memcpy(ctx->x_save, x, x_len);
124 void skein_reset(struct skein_ctx *ctx)
130 * The following two lines rely of the fact that the real Skein
131 * contexts are a union in out context and thus have tha maximum
132 * memory available. The beautiy of C :-) .
135 x_len = ctx->skein_size / 8;
136 /* Restore the chaing variable, reset byte counter */
137 memcpy(x, ctx->x_save, x_len);
139 /* Setup context to process the message */
140 skein_start_new_type(&ctx->m, MSG);
143 int skein_update(struct skein_ctx *ctx, const u8 *msg,
146 int ret = SKEIN_FAIL;
148 skein_assert_ret(ctx, SKEIN_FAIL);
150 switch (ctx->skein_size) {
152 ret = skein_256_update(&ctx->m.s256, msg, msg_byte_cnt);
155 ret = skein_512_update(&ctx->m.s512, msg, msg_byte_cnt);
158 ret = skein_1024_update(&ctx->m.s1024, msg, msg_byte_cnt);
164 int skein_update_bits(struct skein_ctx *ctx, const u8 *msg,
168 * I've used the bit pad implementation from skein_test.c (see NIST CD)
169 * and modified it to use the convenience functions and added some
170 * pointer arithmetic.
177 * only the final Update() call is allowed do partial bytes, else
180 skein_assert_ret((ctx->m.h.T[1] & SKEIN_T1_FLAG_BIT_PAD) == 0 ||
181 msg_bit_cnt == 0, SKEIN_FAIL);
183 /* if number of bits is a multiple of bytes - that's easy */
184 if ((msg_bit_cnt & 0x7) == 0)
185 return skein_update(ctx, msg, msg_bit_cnt >> 3);
187 skein_update(ctx, msg, (msg_bit_cnt >> 3) + 1);
190 * The next line rely on the fact that the real Skein contexts
191 * are a union in our context. After the addition the pointer points to
192 * Skein's real partial block buffer.
193 * If this layout ever changes we have to adapt this as well.
195 up = (u8 *)ctx->m.s256.x + ctx->skein_size / 8;
197 /* set tweak flag for the skein_final call */
198 skein_set_bit_pad_flag(ctx->m.h);
200 /* now "pad" the final partial byte the way NIST likes */
201 /* get the b_cnt value (same location for all block sizes) */
202 length = ctx->m.h.b_cnt;
203 /* internal sanity check: there IS a partial byte in the buffer! */
204 skein_assert(length != 0);
205 /* partial byte bit mask */
206 mask = (u8)(1u << (7 - (msg_bit_cnt & 7)));
207 /* apply bit padding on final byte (in the buffer) */
208 up[length - 1] = (up[length - 1] & (0 - mask)) | mask;
210 return SKEIN_SUCCESS;
213 int skein_final(struct skein_ctx *ctx, u8 *hash)
215 int ret = SKEIN_FAIL;
217 skein_assert_ret(ctx, SKEIN_FAIL);
219 switch (ctx->skein_size) {
221 ret = skein_256_final(&ctx->m.s256, hash);
224 ret = skein_512_final(&ctx->m.s512, hash);
227 ret = skein_1024_final(&ctx->m.s1024, hash);