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
39struct tea_ctx {
40 u32 KEY[4];
41};
42
43struct xtea_ctx {
44 u32 KEY[4];
45};
46
47static 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
62static 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
90static 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
120static 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
135static 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
156static 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
179static 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
200static 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
222static 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
263static int __init tea_mod_init(void)
264{
265 return crypto_register_algs(tea_algs, ARRAY_SIZE(tea_algs));
266}
267
268static void __exit tea_mod_fini(void)
269{
270 crypto_unregister_algs(tea_algs, ARRAY_SIZE(tea_algs));
271}
272
273MODULE_ALIAS_CRYPTO("tea");
274MODULE_ALIAS_CRYPTO("xtea");
275MODULE_ALIAS_CRYPTO("xeta");
276
277module_init(tea_mod_init);
278module_exit(tea_mod_fini);
279
280MODULE_LICENSE("GPL");
281MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");
282