4 * TEA, XTEA, and XETA crypto alogrithms
6 * The TEA and Xtended TEA algorithms were developed by David Wheeler
7 * and Roger Needham at the Computer Laboratory of Cambridge University.
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.
13 * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com
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.
22 #include <linux/init.h>
23 #include <linux/module.h>
25 #include <asm/byteorder.h>
26 #include <linux/crypto.h>
27 #include <linux/types.h>
29 #define TEA_KEY_SIZE 16
30 #define TEA_BLOCK_SIZE 8
32 #define TEA_DELTA 0x9e3779b9
34 #define XTEA_KEY_SIZE 16
35 #define XTEA_BLOCK_SIZE 8
36 #define XTEA_ROUNDS 32
37 #define XTEA_DELTA 0x9e3779b9
47 static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
50 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
51 const __le32 *key = (const __le32 *)in_key;
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]);
62 static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
66 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
67 const __le32 *in = (const __le32 *)src;
68 __le32 *out = (__le32 *)dst;
70 y = le32_to_cpu(in[0]);
71 z = le32_to_cpu(in[1]);
82 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
83 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
86 out[0] = cpu_to_le32(y);
87 out[1] = cpu_to_le32(z);
90 static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
94 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
95 const __le32 *in = (const __le32 *)src;
96 __le32 *out = (__le32 *)dst;
98 y = le32_to_cpu(in[0]);
99 z = le32_to_cpu(in[1]);
106 sum = TEA_DELTA << 5;
111 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
112 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
116 out[0] = cpu_to_le32(y);
117 out[1] = cpu_to_le32(z);
120 static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
121 unsigned int key_len)
123 struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
124 const __le32 *key = (const __le32 *)in_key;
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]);
135 static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
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;
143 y = le32_to_cpu(in[0]);
144 z = le32_to_cpu(in[1]);
146 while (sum != limit) {
147 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
149 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
152 out[0] = cpu_to_le32(y);
153 out[1] = cpu_to_le32(z);
156 static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
159 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
160 const __le32 *in = (const __le32 *)src;
161 __le32 *out = (__le32 *)dst;
163 y = le32_to_cpu(in[0]);
164 z = le32_to_cpu(in[1]);
166 sum = XTEA_DELTA * XTEA_ROUNDS;
169 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
171 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
174 out[0] = cpu_to_le32(y);
175 out[1] = cpu_to_le32(z);
179 static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
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;
187 y = le32_to_cpu(in[0]);
188 z = le32_to_cpu(in[1]);
190 while (sum != limit) {
191 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
193 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
196 out[0] = cpu_to_le32(y);
197 out[1] = cpu_to_le32(z);
200 static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
203 struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
204 const __le32 *in = (const __le32 *)src;
205 __le32 *out = (__le32 *)dst;
207 y = le32_to_cpu(in[0]);
208 z = le32_to_cpu(in[1]);
210 sum = XTEA_DELTA * XTEA_ROUNDS;
213 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
215 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
218 out[0] = cpu_to_le32(y);
219 out[1] = cpu_to_le32(z);
222 static struct crypto_alg tea_alg = {
224 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
225 .cra_blocksize = TEA_BLOCK_SIZE,
226 .cra_ctxsize = sizeof (struct tea_ctx),
228 .cra_module = THIS_MODULE,
229 .cra_list = LIST_HEAD_INIT(tea_alg.cra_list),
230 .cra_u = { .cipher = {
231 .cia_min_keysize = TEA_KEY_SIZE,
232 .cia_max_keysize = TEA_KEY_SIZE,
233 .cia_setkey = tea_setkey,
234 .cia_encrypt = tea_encrypt,
235 .cia_decrypt = tea_decrypt } }
238 static struct crypto_alg xtea_alg = {
240 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
241 .cra_blocksize = XTEA_BLOCK_SIZE,
242 .cra_ctxsize = sizeof (struct xtea_ctx),
244 .cra_module = THIS_MODULE,
245 .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list),
246 .cra_u = { .cipher = {
247 .cia_min_keysize = XTEA_KEY_SIZE,
248 .cia_max_keysize = XTEA_KEY_SIZE,
249 .cia_setkey = xtea_setkey,
250 .cia_encrypt = xtea_encrypt,
251 .cia_decrypt = xtea_decrypt } }
254 static struct crypto_alg xeta_alg = {
256 .cra_flags = CRYPTO_ALG_TYPE_CIPHER,
257 .cra_blocksize = XTEA_BLOCK_SIZE,
258 .cra_ctxsize = sizeof (struct xtea_ctx),
260 .cra_module = THIS_MODULE,
261 .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list),
262 .cra_u = { .cipher = {
263 .cia_min_keysize = XTEA_KEY_SIZE,
264 .cia_max_keysize = XTEA_KEY_SIZE,
265 .cia_setkey = xtea_setkey,
266 .cia_encrypt = xeta_encrypt,
267 .cia_decrypt = xeta_decrypt } }
270 static int __init tea_mod_init(void)
274 ret = crypto_register_alg(&tea_alg);
278 ret = crypto_register_alg(&xtea_alg);
280 crypto_unregister_alg(&tea_alg);
284 ret = crypto_register_alg(&xeta_alg);
286 crypto_unregister_alg(&tea_alg);
287 crypto_unregister_alg(&xtea_alg);
295 static void __exit tea_mod_fini(void)
297 crypto_unregister_alg(&tea_alg);
298 crypto_unregister_alg(&xtea_alg);
299 crypto_unregister_alg(&xeta_alg);
302 MODULE_ALIAS("xtea");
303 MODULE_ALIAS("xeta");
305 module_init(tea_mod_init);
306 module_exit(tea_mod_fini);
308 MODULE_LICENSE("GPL");
309 MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");