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1 | /* | |
2 | * Cryptographic API. | |
3 | * | |
4 | * TEA, XTEA, and XETA crypto alogrithms | |
5 | * | |
6 | * The TEA and Xtended TEA algorithms were developed by David Wheeler | |
7 | * and Roger Needham at the Computer Laboratory of Cambridge University. | |
8 | * | |
9 | * Due to the order of evaluation in XTEA many people have incorrectly | |
10 | * implemented it. XETA (XTEA in the wrong order), exists for | |
11 | * compatibility with these implementations. | |
12 | * | |
13 | * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com | |
14 | * | |
15 | * This program is free software; you can redistribute it and/or modify | |
16 | * it under the terms of the GNU General Public License as published by | |
17 | * the Free Software Foundation; either version 2 of the License, or | |
18 | * (at your option) any later version. | |
19 | * | |
20 | */ | |
21 | ||
22 | #include <linux/init.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/mm.h> | |
25 | #include <asm/byteorder.h> | |
26 | #include <linux/crypto.h> | |
27 | #include <linux/types.h> | |
28 | ||
29 | #define TEA_KEY_SIZE 16 | |
30 | #define TEA_BLOCK_SIZE 8 | |
31 | #define TEA_ROUNDS 32 | |
32 | #define TEA_DELTA 0x9e3779b9 | |
33 | ||
34 | #define XTEA_KEY_SIZE 16 | |
35 | #define XTEA_BLOCK_SIZE 8 | |
36 | #define XTEA_ROUNDS 32 | |
37 | #define XTEA_DELTA 0x9e3779b9 | |
38 | ||
39 | struct tea_ctx { | |
40 | u32 KEY[4]; | |
41 | }; | |
42 | ||
43 | struct xtea_ctx { | |
44 | u32 KEY[4]; | |
45 | }; | |
46 | ||
47 | static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key, | |
48 | unsigned int key_len) | |
49 | { | |
50 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); | |
51 | const __le32 *key = (const __le32 *)in_key; | |
52 | ||
53 | ctx->KEY[0] = le32_to_cpu(key[0]); | |
54 | ctx->KEY[1] = le32_to_cpu(key[1]); | |
55 | ctx->KEY[2] = le32_to_cpu(key[2]); | |
56 | ctx->KEY[3] = le32_to_cpu(key[3]); | |
57 | ||
58 | return 0; | |
59 | ||
60 | } | |
61 | ||
62 | static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) | |
63 | { | |
64 | u32 y, z, n, sum = 0; | |
65 | u32 k0, k1, k2, k3; | |
66 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); | |
67 | const __le32 *in = (const __le32 *)src; | |
68 | __le32 *out = (__le32 *)dst; | |
69 | ||
70 | y = le32_to_cpu(in[0]); | |
71 | z = le32_to_cpu(in[1]); | |
72 | ||
73 | k0 = ctx->KEY[0]; | |
74 | k1 = ctx->KEY[1]; | |
75 | k2 = ctx->KEY[2]; | |
76 | k3 = ctx->KEY[3]; | |
77 | ||
78 | n = TEA_ROUNDS; | |
79 | ||
80 | while (n-- > 0) { | |
81 | sum += TEA_DELTA; | |
82 | y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); | |
83 | z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); | |
84 | } | |
85 | ||
86 | out[0] = cpu_to_le32(y); | |
87 | out[1] = cpu_to_le32(z); | |
88 | } | |
89 | ||
90 | static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) | |
91 | { | |
92 | u32 y, z, n, sum; | |
93 | u32 k0, k1, k2, k3; | |
94 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); | |
95 | const __le32 *in = (const __le32 *)src; | |
96 | __le32 *out = (__le32 *)dst; | |
97 | ||
98 | y = le32_to_cpu(in[0]); | |
99 | z = le32_to_cpu(in[1]); | |
100 | ||
101 | k0 = ctx->KEY[0]; | |
102 | k1 = ctx->KEY[1]; | |
103 | k2 = ctx->KEY[2]; | |
104 | k3 = ctx->KEY[3]; | |
105 | ||
106 | sum = TEA_DELTA << 5; | |
107 | ||
108 | n = TEA_ROUNDS; | |
109 | ||
110 | while (n-- > 0) { | |
111 | z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); | |
112 | y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); | |
113 | sum -= TEA_DELTA; | |
114 | } | |
115 | ||
116 | out[0] = cpu_to_le32(y); | |
117 | out[1] = cpu_to_le32(z); | |
118 | } | |
119 | ||
120 | static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key, | |
121 | unsigned int key_len) | |
122 | { | |
123 | struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); | |
124 | const __le32 *key = (const __le32 *)in_key; | |
125 | ||
126 | ctx->KEY[0] = le32_to_cpu(key[0]); | |
127 | ctx->KEY[1] = le32_to_cpu(key[1]); | |
128 | ctx->KEY[2] = le32_to_cpu(key[2]); | |
129 | ctx->KEY[3] = le32_to_cpu(key[3]); | |
130 | ||
131 | return 0; | |
132 | ||
133 | } | |
134 | ||
135 | static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) | |
136 | { | |
137 | u32 y, z, sum = 0; | |
138 | u32 limit = XTEA_DELTA * XTEA_ROUNDS; | |
139 | struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); | |
140 | const __le32 *in = (const __le32 *)src; | |
141 | __le32 *out = (__le32 *)dst; | |
142 | ||
143 | y = le32_to_cpu(in[0]); | |
144 | z = le32_to_cpu(in[1]); | |
145 | ||
146 | while (sum != limit) { | |
147 | y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]); | |
148 | sum += XTEA_DELTA; | |
149 | z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]); | |
150 | } | |
151 | ||
152 | out[0] = cpu_to_le32(y); | |
153 | out[1] = cpu_to_le32(z); | |
154 | } | |
155 | ||
156 | static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) | |
157 | { | |
158 | u32 y, z, sum; | |
159 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); | |
160 | const __le32 *in = (const __le32 *)src; | |
161 | __le32 *out = (__le32 *)dst; | |
162 | ||
163 | y = le32_to_cpu(in[0]); | |
164 | z = le32_to_cpu(in[1]); | |
165 | ||
166 | sum = XTEA_DELTA * XTEA_ROUNDS; | |
167 | ||
168 | while (sum) { | |
169 | z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]); | |
170 | sum -= XTEA_DELTA; | |
171 | y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]); | |
172 | } | |
173 | ||
174 | out[0] = cpu_to_le32(y); | |
175 | out[1] = cpu_to_le32(z); | |
176 | } | |
177 | ||
178 | ||
179 | static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) | |
180 | { | |
181 | u32 y, z, sum = 0; | |
182 | u32 limit = XTEA_DELTA * XTEA_ROUNDS; | |
183 | struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); | |
184 | const __le32 *in = (const __le32 *)src; | |
185 | __le32 *out = (__le32 *)dst; | |
186 | ||
187 | y = le32_to_cpu(in[0]); | |
188 | z = le32_to_cpu(in[1]); | |
189 | ||
190 | while (sum != limit) { | |
191 | y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3]; | |
192 | sum += XTEA_DELTA; | |
193 | z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3]; | |
194 | } | |
195 | ||
196 | out[0] = cpu_to_le32(y); | |
197 | out[1] = cpu_to_le32(z); | |
198 | } | |
199 | ||
200 | static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) | |
201 | { | |
202 | u32 y, z, sum; | |
203 | struct tea_ctx *ctx = crypto_tfm_ctx(tfm); | |
204 | const __le32 *in = (const __le32 *)src; | |
205 | __le32 *out = (__le32 *)dst; | |
206 | ||
207 | y = le32_to_cpu(in[0]); | |
208 | z = le32_to_cpu(in[1]); | |
209 | ||
210 | sum = XTEA_DELTA * XTEA_ROUNDS; | |
211 | ||
212 | while (sum) { | |
213 | z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3]; | |
214 | sum -= XTEA_DELTA; | |
215 | y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3]; | |
216 | } | |
217 | ||
218 | out[0] = cpu_to_le32(y); | |
219 | out[1] = cpu_to_le32(z); | |
220 | } | |
221 | ||
222 | static struct crypto_alg tea_algs[3] = { { | |
223 | .cra_name = "tea", | |
224 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, | |
225 | .cra_blocksize = TEA_BLOCK_SIZE, | |
226 | .cra_ctxsize = sizeof (struct tea_ctx), | |
227 | .cra_alignmask = 3, | |
228 | .cra_module = THIS_MODULE, | |
229 | .cra_u = { .cipher = { | |
230 | .cia_min_keysize = TEA_KEY_SIZE, | |
231 | .cia_max_keysize = TEA_KEY_SIZE, | |
232 | .cia_setkey = tea_setkey, | |
233 | .cia_encrypt = tea_encrypt, | |
234 | .cia_decrypt = tea_decrypt } } | |
235 | }, { | |
236 | .cra_name = "xtea", | |
237 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, | |
238 | .cra_blocksize = XTEA_BLOCK_SIZE, | |
239 | .cra_ctxsize = sizeof (struct xtea_ctx), | |
240 | .cra_alignmask = 3, | |
241 | .cra_module = THIS_MODULE, | |
242 | .cra_u = { .cipher = { | |
243 | .cia_min_keysize = XTEA_KEY_SIZE, | |
244 | .cia_max_keysize = XTEA_KEY_SIZE, | |
245 | .cia_setkey = xtea_setkey, | |
246 | .cia_encrypt = xtea_encrypt, | |
247 | .cia_decrypt = xtea_decrypt } } | |
248 | }, { | |
249 | .cra_name = "xeta", | |
250 | .cra_flags = CRYPTO_ALG_TYPE_CIPHER, | |
251 | .cra_blocksize = XTEA_BLOCK_SIZE, | |
252 | .cra_ctxsize = sizeof (struct xtea_ctx), | |
253 | .cra_alignmask = 3, | |
254 | .cra_module = THIS_MODULE, | |
255 | .cra_u = { .cipher = { | |
256 | .cia_min_keysize = XTEA_KEY_SIZE, | |
257 | .cia_max_keysize = XTEA_KEY_SIZE, | |
258 | .cia_setkey = xtea_setkey, | |
259 | .cia_encrypt = xeta_encrypt, | |
260 | .cia_decrypt = xeta_decrypt } } | |
261 | } }; | |
262 | ||
263 | static int __init tea_mod_init(void) | |
264 | { | |
265 | return crypto_register_algs(tea_algs, ARRAY_SIZE(tea_algs)); | |
266 | } | |
267 | ||
268 | static void __exit tea_mod_fini(void) | |
269 | { | |
270 | crypto_unregister_algs(tea_algs, ARRAY_SIZE(tea_algs)); | |
271 | } | |
272 | ||
273 | MODULE_ALIAS_CRYPTO("tea"); | |
274 | MODULE_ALIAS_CRYPTO("xtea"); | |
275 | MODULE_ALIAS_CRYPTO("xeta"); | |
276 | ||
277 | module_init(tea_mod_init); | |
278 | module_exit(tea_mod_fini); | |
279 | ||
280 | MODULE_LICENSE("GPL"); | |
281 | MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms"); |