crypto/tea.c

   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 <asm/scatterlist.h>
  27 #include <linux/crypto.h>
  28 #include <linux/types.h>
  29
  30 #define TEA_KEY_SIZE            16
  31 #define TEA_BLOCK_SIZE          8
  32 #define TEA_ROUNDS              32
  33 #define TEA_DELTA               0x9e3779b9
  34
  35 #define XTEA_KEY_SIZE           16
  36 #define XTEA_BLOCK_SIZE         8
  37 #define XTEA_ROUNDS             32
  38 #define XTEA_DELTA              0x9e3779b9
  39
  40 struct tea_ctx {
  41         u32 KEY[4];
  42 };
  43
  44 struct xtea_ctx {
  45         u32 KEY[4];
  46 };
  47
  48 static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
  49                       unsigned int key_len)
  50 {
  51         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
  52         const __le32 *key = (const __le32 *)in_key;
  53
  54         ctx->KEY[0] = le32_to_cpu(key[0]);
  55         ctx->KEY[1] = le32_to_cpu(key[1]);
  56         ctx->KEY[2] = le32_to_cpu(key[2]);
  57         ctx->KEY[3] = le32_to_cpu(key[3]);
  58
  59         return 0;
  60
  61 }
  62
  63 static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  64 {
  65         u32 y, z, n, sum = 0;
  66         u32 k0, k1, k2, k3;
  67         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
  68         const __le32 *in = (const __le32 *)src;
  69         __le32 *out = (__le32 *)dst;
  70
  71         y = le32_to_cpu(in[0]);
  72         z = le32_to_cpu(in[1]);
  73
  74         k0 = ctx->KEY[0];
  75         k1 = ctx->KEY[1];
  76         k2 = ctx->KEY[2];
  77         k3 = ctx->KEY[3];
  78
  79         n = TEA_ROUNDS;
  80
  81         while (n-- > 0) {
  82                 sum += TEA_DELTA;
  83                 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
  84                 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
  85         }
  86
  87         out[0] = cpu_to_le32(y);
  88         out[1] = cpu_to_le32(z);
  89 }
  90
  91 static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  92 {
  93         u32 y, z, n, sum;
  94         u32 k0, k1, k2, k3;
  95         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
  96         const __le32 *in = (const __le32 *)src;
  97         __le32 *out = (__le32 *)dst;
  98
  99         y = le32_to_cpu(in[0]);
 100         z = le32_to_cpu(in[1]);
 101
 102         k0 = ctx->KEY[0];
 103         k1 = ctx->KEY[1];
 104         k2 = ctx->KEY[2];
 105         k3 = ctx->KEY[3];
 106
 107         sum = TEA_DELTA << 5;
 108
 109         n = TEA_ROUNDS;
 110
 111         while (n-- > 0) {
 112                 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
 113                 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
 114                 sum -= TEA_DELTA;
 115         }
 116
 117         out[0] = cpu_to_le32(y);
 118         out[1] = cpu_to_le32(z);
 119 }
 120
 121 static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
 122                        unsigned int key_len)
 123 {
 124         struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
 125         const __le32 *key = (const __le32 *)in_key;
 126
 127         ctx->KEY[0] = le32_to_cpu(key[0]);
 128         ctx->KEY[1] = le32_to_cpu(key[1]);
 129         ctx->KEY[2] = le32_to_cpu(key[2]);
 130         ctx->KEY[3] = le32_to_cpu(key[3]);
 131
 132         return 0;
 133
 134 }
 135
 136 static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 137 {
 138         u32 y, z, sum = 0;
 139         u32 limit = XTEA_DELTA * XTEA_ROUNDS;
 140         struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
 141         const __le32 *in = (const __le32 *)src;
 142         __le32 *out = (__le32 *)dst;
 143
 144         y = le32_to_cpu(in[0]);
 145         z = le32_to_cpu(in[1]);
 146
 147         while (sum != limit) {
 148                 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
 149                 sum += XTEA_DELTA;
 150                 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
 151         }
 152
 153         out[0] = cpu_to_le32(y);
 154         out[1] = cpu_to_le32(z);
 155 }
 156
 157 static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 158 {
 159         u32 y, z, sum;
 160         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
 161         const __le32 *in = (const __le32 *)src;
 162         __le32 *out = (__le32 *)dst;
 163
 164         y = le32_to_cpu(in[0]);
 165         z = le32_to_cpu(in[1]);
 166
 167         sum = XTEA_DELTA * XTEA_ROUNDS;
 168
 169         while (sum) {
 170                 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
 171                 sum -= XTEA_DELTA;
 172                 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
 173         }
 174
 175         out[0] = cpu_to_le32(y);
 176         out[1] = cpu_to_le32(z);
 177 }
 178
 179
 180 static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 181 {
 182         u32 y, z, sum = 0;
 183         u32 limit = XTEA_DELTA * XTEA_ROUNDS;
 184         struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
 185         const __le32 *in = (const __le32 *)src;
 186         __le32 *out = (__le32 *)dst;
 187
 188         y = le32_to_cpu(in[0]);
 189         z = le32_to_cpu(in[1]);
 190
 191         while (sum != limit) {
 192                 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
 193                 sum += XTEA_DELTA;
 194                 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
 195         }
 196
 197         out[0] = cpu_to_le32(y);
 198         out[1] = cpu_to_le32(z);
 199 }
 200
 201 static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 202 {
 203         u32 y, z, sum;
 204         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
 205         const __le32 *in = (const __le32 *)src;
 206         __le32 *out = (__le32 *)dst;
 207
 208         y = le32_to_cpu(in[0]);
 209         z = le32_to_cpu(in[1]);
 210
 211         sum = XTEA_DELTA * XTEA_ROUNDS;
 212
 213         while (sum) {
 214                 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
 215                 sum -= XTEA_DELTA;
 216                 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
 217         }
 218
 219         out[0] = cpu_to_le32(y);
 220         out[1] = cpu_to_le32(z);
 221 }
 222
 223 static struct crypto_alg tea_alg = {
 224         .cra_name               =       "tea",
 225         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 226         .cra_blocksize          =       TEA_BLOCK_SIZE,
 227         .cra_ctxsize            =       sizeof (struct tea_ctx),
 228         .cra_alignmask          =       3,
 229         .cra_module             =       THIS_MODULE,
 230         .cra_list               =       LIST_HEAD_INIT(tea_alg.cra_list),
 231         .cra_u                  =       { .cipher = {
 232         .cia_min_keysize        =       TEA_KEY_SIZE,
 233         .cia_max_keysize        =       TEA_KEY_SIZE,
 234         .cia_setkey             =       tea_setkey,
 235         .cia_encrypt            =       tea_encrypt,
 236         .cia_decrypt            =       tea_decrypt } }
 237 };
 238
 239 static struct crypto_alg xtea_alg = {
 240         .cra_name               =       "xtea",
 241         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 242         .cra_blocksize          =       XTEA_BLOCK_SIZE,
 243         .cra_ctxsize            =       sizeof (struct xtea_ctx),
 244         .cra_alignmask          =       3,
 245         .cra_module             =       THIS_MODULE,
 246         .cra_list               =       LIST_HEAD_INIT(xtea_alg.cra_list),
 247         .cra_u                  =       { .cipher = {
 248         .cia_min_keysize        =       XTEA_KEY_SIZE,
 249         .cia_max_keysize        =       XTEA_KEY_SIZE,
 250         .cia_setkey             =       xtea_setkey,
 251         .cia_encrypt            =       xtea_encrypt,
 252         .cia_decrypt            =       xtea_decrypt } }
 253 };
 254
 255 static struct crypto_alg xeta_alg = {
 256         .cra_name               =       "xeta",
 257         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 258         .cra_blocksize          =       XTEA_BLOCK_SIZE,
 259         .cra_ctxsize            =       sizeof (struct xtea_ctx),
 260         .cra_alignmask          =       3,
 261         .cra_module             =       THIS_MODULE,
 262         .cra_list               =       LIST_HEAD_INIT(xtea_alg.cra_list),
 263         .cra_u                  =       { .cipher = {
 264         .cia_min_keysize        =       XTEA_KEY_SIZE,
 265         .cia_max_keysize        =       XTEA_KEY_SIZE,
 266         .cia_setkey             =       xtea_setkey,
 267         .cia_encrypt            =       xeta_encrypt,
 268         .cia_decrypt            =       xeta_decrypt } }
 269 };
 270
 271 static int __init init(void)
 272 {
 273         int ret = 0;
 274
 275         ret = crypto_register_alg(&tea_alg);
 276         if (ret < 0)
 277                 goto out;
 278
 279         ret = crypto_register_alg(&xtea_alg);
 280         if (ret < 0) {
 281                 crypto_unregister_alg(&tea_alg);
 282                 goto out;
 283         }
 284
 285         ret = crypto_register_alg(&xeta_alg);
 286         if (ret < 0) {
 287                 crypto_unregister_alg(&tea_alg);
 288                 crypto_unregister_alg(&xtea_alg);
 289                 goto out;
 290         }
 291
 292 out:
 293         return ret;
 294 }
 295
 296 static void __exit fini(void)
 297 {
 298         crypto_unregister_alg(&tea_alg);
 299         crypto_unregister_alg(&xtea_alg);
 300         crypto_unregister_alg(&xeta_alg);
 301 }
 302
 303 MODULE_ALIAS("xtea");
 304 MODULE_ALIAS("xeta");
 305
 306 module_init(init);
 307 module_exit(fini);
 308
 309 MODULE_LICENSE("GPL");
 310 MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");