mvsas: increase port type detection delay to suit Seagate's 10k6 drive ST3450856SS...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / crypto / salsa20_generic.c
blobb07d55981741578b951b8accbe6cf2b47c771f95
1 /*
2 * Salsa20: Salsa20 stream cipher algorithm
4 * Copyright (c) 2007 Tan Swee Heng <thesweeheng@gmail.com>
6 * Derived from:
7 * - salsa20.c: Public domain C code by Daniel J. Bernstein <djb@cr.yp.to>
9 * Salsa20 is a stream cipher candidate in eSTREAM, the ECRYPT Stream
10 * Cipher Project. It is designed by Daniel J. Bernstein <djb@cr.yp.to>.
11 * More information about eSTREAM and Salsa20 can be found here:
12 * http://www.ecrypt.eu.org/stream/
13 * http://cr.yp.to/snuffle.html
15 * This program is free software; you can redistribute it and/or modify it
16 * under the terms of the GNU General Public License as published by the Free
17 * Software Foundation; either version 2 of the License, or (at your option)
18 * any later version.
22 #include <linux/init.h>
23 #include <linux/module.h>
24 #include <linux/errno.h>
25 #include <linux/crypto.h>
26 #include <linux/types.h>
27 #include <crypto/algapi.h>
28 #include <asm/byteorder.h>
30 #define SALSA20_IV_SIZE 8U
31 #define SALSA20_MIN_KEY_SIZE 16U
32 #define SALSA20_MAX_KEY_SIZE 32U
35 * Start of code taken from D. J. Bernstein's reference implementation.
36 * With some modifications and optimizations made to suit our needs.
40 salsa20-ref.c version 20051118
41 D. J. Bernstein
42 Public domain.
45 #define ROTATE(v,n) (((v) << (n)) | ((v) >> (32 - (n))))
46 #define XOR(v,w) ((v) ^ (w))
47 #define PLUS(v,w) (((v) + (w)))
48 #define PLUSONE(v) (PLUS((v),1))
49 #define U32TO8_LITTLE(p, v) \
50 { (p)[0] = (v >> 0) & 0xff; (p)[1] = (v >> 8) & 0xff; \
51 (p)[2] = (v >> 16) & 0xff; (p)[3] = (v >> 24) & 0xff; }
52 #define U8TO32_LITTLE(p) \
53 (((u32)((p)[0]) ) | ((u32)((p)[1]) << 8) | \
54 ((u32)((p)[2]) << 16) | ((u32)((p)[3]) << 24) )
56 struct salsa20_ctx
58 u32 input[16];
61 static void salsa20_wordtobyte(u8 output[64], const u32 input[16])
63 u32 x[16];
64 int i;
66 memcpy(x, input, sizeof(x));
67 for (i = 20; i > 0; i -= 2) {
68 x[ 4] = XOR(x[ 4],ROTATE(PLUS(x[ 0],x[12]), 7));
69 x[ 8] = XOR(x[ 8],ROTATE(PLUS(x[ 4],x[ 0]), 9));
70 x[12] = XOR(x[12],ROTATE(PLUS(x[ 8],x[ 4]),13));
71 x[ 0] = XOR(x[ 0],ROTATE(PLUS(x[12],x[ 8]),18));
72 x[ 9] = XOR(x[ 9],ROTATE(PLUS(x[ 5],x[ 1]), 7));
73 x[13] = XOR(x[13],ROTATE(PLUS(x[ 9],x[ 5]), 9));
74 x[ 1] = XOR(x[ 1],ROTATE(PLUS(x[13],x[ 9]),13));
75 x[ 5] = XOR(x[ 5],ROTATE(PLUS(x[ 1],x[13]),18));
76 x[14] = XOR(x[14],ROTATE(PLUS(x[10],x[ 6]), 7));
77 x[ 2] = XOR(x[ 2],ROTATE(PLUS(x[14],x[10]), 9));
78 x[ 6] = XOR(x[ 6],ROTATE(PLUS(x[ 2],x[14]),13));
79 x[10] = XOR(x[10],ROTATE(PLUS(x[ 6],x[ 2]),18));
80 x[ 3] = XOR(x[ 3],ROTATE(PLUS(x[15],x[11]), 7));
81 x[ 7] = XOR(x[ 7],ROTATE(PLUS(x[ 3],x[15]), 9));
82 x[11] = XOR(x[11],ROTATE(PLUS(x[ 7],x[ 3]),13));
83 x[15] = XOR(x[15],ROTATE(PLUS(x[11],x[ 7]),18));
84 x[ 1] = XOR(x[ 1],ROTATE(PLUS(x[ 0],x[ 3]), 7));
85 x[ 2] = XOR(x[ 2],ROTATE(PLUS(x[ 1],x[ 0]), 9));
86 x[ 3] = XOR(x[ 3],ROTATE(PLUS(x[ 2],x[ 1]),13));
87 x[ 0] = XOR(x[ 0],ROTATE(PLUS(x[ 3],x[ 2]),18));
88 x[ 6] = XOR(x[ 6],ROTATE(PLUS(x[ 5],x[ 4]), 7));
89 x[ 7] = XOR(x[ 7],ROTATE(PLUS(x[ 6],x[ 5]), 9));
90 x[ 4] = XOR(x[ 4],ROTATE(PLUS(x[ 7],x[ 6]),13));
91 x[ 5] = XOR(x[ 5],ROTATE(PLUS(x[ 4],x[ 7]),18));
92 x[11] = XOR(x[11],ROTATE(PLUS(x[10],x[ 9]), 7));
93 x[ 8] = XOR(x[ 8],ROTATE(PLUS(x[11],x[10]), 9));
94 x[ 9] = XOR(x[ 9],ROTATE(PLUS(x[ 8],x[11]),13));
95 x[10] = XOR(x[10],ROTATE(PLUS(x[ 9],x[ 8]),18));
96 x[12] = XOR(x[12],ROTATE(PLUS(x[15],x[14]), 7));
97 x[13] = XOR(x[13],ROTATE(PLUS(x[12],x[15]), 9));
98 x[14] = XOR(x[14],ROTATE(PLUS(x[13],x[12]),13));
99 x[15] = XOR(x[15],ROTATE(PLUS(x[14],x[13]),18));
101 for (i = 0; i < 16; ++i)
102 x[i] = PLUS(x[i],input[i]);
103 for (i = 0; i < 16; ++i)
104 U32TO8_LITTLE(output + 4 * i,x[i]);
107 static const char sigma[16] = "expand 32-byte k";
108 static const char tau[16] = "expand 16-byte k";
110 static void salsa20_keysetup(struct salsa20_ctx *ctx, const u8 *k, u32 kbytes)
112 const char *constants;
114 ctx->input[1] = U8TO32_LITTLE(k + 0);
115 ctx->input[2] = U8TO32_LITTLE(k + 4);
116 ctx->input[3] = U8TO32_LITTLE(k + 8);
117 ctx->input[4] = U8TO32_LITTLE(k + 12);
118 if (kbytes == 32) { /* recommended */
119 k += 16;
120 constants = sigma;
121 } else { /* kbytes == 16 */
122 constants = tau;
124 ctx->input[11] = U8TO32_LITTLE(k + 0);
125 ctx->input[12] = U8TO32_LITTLE(k + 4);
126 ctx->input[13] = U8TO32_LITTLE(k + 8);
127 ctx->input[14] = U8TO32_LITTLE(k + 12);
128 ctx->input[0] = U8TO32_LITTLE(constants + 0);
129 ctx->input[5] = U8TO32_LITTLE(constants + 4);
130 ctx->input[10] = U8TO32_LITTLE(constants + 8);
131 ctx->input[15] = U8TO32_LITTLE(constants + 12);
134 static void salsa20_ivsetup(struct salsa20_ctx *ctx, const u8 *iv)
136 ctx->input[6] = U8TO32_LITTLE(iv + 0);
137 ctx->input[7] = U8TO32_LITTLE(iv + 4);
138 ctx->input[8] = 0;
139 ctx->input[9] = 0;
142 static void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, u8 *dst,
143 const u8 *src, unsigned int bytes)
145 u8 buf[64];
147 if (dst != src)
148 memcpy(dst, src, bytes);
150 while (bytes) {
151 salsa20_wordtobyte(buf, ctx->input);
153 ctx->input[8] = PLUSONE(ctx->input[8]);
154 if (!ctx->input[8])
155 ctx->input[9] = PLUSONE(ctx->input[9]);
157 if (bytes <= 64) {
158 crypto_xor(dst, buf, bytes);
159 return;
162 crypto_xor(dst, buf, 64);
163 bytes -= 64;
164 dst += 64;
169 * End of code taken from D. J. Bernstein's reference implementation.
172 static int setkey(struct crypto_tfm *tfm, const u8 *key,
173 unsigned int keysize)
175 struct salsa20_ctx *ctx = crypto_tfm_ctx(tfm);
176 salsa20_keysetup(ctx, key, keysize);
177 return 0;
180 static int encrypt(struct blkcipher_desc *desc,
181 struct scatterlist *dst, struct scatterlist *src,
182 unsigned int nbytes)
184 struct blkcipher_walk walk;
185 struct crypto_blkcipher *tfm = desc->tfm;
186 struct salsa20_ctx *ctx = crypto_blkcipher_ctx(tfm);
187 int err;
189 blkcipher_walk_init(&walk, dst, src, nbytes);
190 err = blkcipher_walk_virt_block(desc, &walk, 64);
192 salsa20_ivsetup(ctx, walk.iv);
194 if (likely(walk.nbytes == nbytes))
196 salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
197 walk.src.virt.addr, nbytes);
198 return blkcipher_walk_done(desc, &walk, 0);
201 while (walk.nbytes >= 64) {
202 salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
203 walk.src.virt.addr,
204 walk.nbytes - (walk.nbytes % 64));
205 err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64);
208 if (walk.nbytes) {
209 salsa20_encrypt_bytes(ctx, walk.dst.virt.addr,
210 walk.src.virt.addr, walk.nbytes);
211 err = blkcipher_walk_done(desc, &walk, 0);
214 return err;
217 static struct crypto_alg alg = {
218 .cra_name = "salsa20",
219 .cra_driver_name = "salsa20-generic",
220 .cra_priority = 100,
221 .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER,
222 .cra_type = &crypto_blkcipher_type,
223 .cra_blocksize = 1,
224 .cra_ctxsize = sizeof(struct salsa20_ctx),
225 .cra_alignmask = 3,
226 .cra_module = THIS_MODULE,
227 .cra_list = LIST_HEAD_INIT(alg.cra_list),
228 .cra_u = {
229 .blkcipher = {
230 .setkey = setkey,
231 .encrypt = encrypt,
232 .decrypt = encrypt,
233 .min_keysize = SALSA20_MIN_KEY_SIZE,
234 .max_keysize = SALSA20_MAX_KEY_SIZE,
235 .ivsize = SALSA20_IV_SIZE,
240 static int __init salsa20_generic_mod_init(void)
242 return crypto_register_alg(&alg);
245 static void __exit salsa20_generic_mod_fini(void)
247 crypto_unregister_alg(&alg);
250 module_init(salsa20_generic_mod_init);
251 module_exit(salsa20_generic_mod_fini);
253 MODULE_LICENSE("GPL");
254 MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm");
255 MODULE_ALIAS("salsa20");