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(void *ctx_arg, const u8 *in_key,
  49                        unsigned int key_len, u32 *flags)
  50 {
  51         struct tea_ctx *ctx = ctx_arg;
  52         const __le32 *key = (const __le32 *)in_key;
  53
  54         if (key_len != 16)
  55         {
  56                 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
  57                 return -EINVAL;
  58         }
  59
  60         ctx->KEY[0] = le32_to_cpu(key[0]);
  61         ctx->KEY[1] = le32_to_cpu(key[1]);
  62         ctx->KEY[2] = le32_to_cpu(key[2]);
  63         ctx->KEY[3] = le32_to_cpu(key[3]);
  64
  65         return 0;
  66
  67 }
  68
  69 static void tea_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
  70 {
  71         u32 y, z, n, sum = 0;
  72         u32 k0, k1, k2, k3;
  73
  74         struct tea_ctx *ctx = ctx_arg;
  75         const __le32 *in = (const __le32 *)src;
  76         __le32 *out = (__le32 *)dst;
  77
  78         y = le32_to_cpu(in[0]);
  79         z = le32_to_cpu(in[1]);
  80
  81         k0 = ctx->KEY[0];
  82         k1 = ctx->KEY[1];
  83         k2 = ctx->KEY[2];
  84         k3 = ctx->KEY[3];
  85
  86         n = TEA_ROUNDS;
  87
  88         while (n-- > 0) {
  89                 sum += TEA_DELTA;
  90                 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
  91                 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
  92         }
  93
  94         out[0] = cpu_to_le32(y);
  95         out[1] = cpu_to_le32(z);
  96 }
  97
  98 static void tea_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
  99 {
 100         u32 y, z, n, sum;
 101         u32 k0, k1, k2, k3;
 102         struct tea_ctx *ctx = ctx_arg;
 103         const __le32 *in = (const __le32 *)src;
 104         __le32 *out = (__le32 *)dst;
 105
 106         y = le32_to_cpu(in[0]);
 107         z = le32_to_cpu(in[1]);
 108
 109         k0 = ctx->KEY[0];
 110         k1 = ctx->KEY[1];
 111         k2 = ctx->KEY[2];
 112         k3 = ctx->KEY[3];
 113
 114         sum = TEA_DELTA << 5;
 115
 116         n = TEA_ROUNDS;
 117
 118         while (n-- > 0) {
 119                 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
 120                 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
 121                 sum -= TEA_DELTA;
 122         }
 123
 124         out[0] = cpu_to_le32(y);
 125         out[1] = cpu_to_le32(z);
 126 }
 127
 128 static int xtea_setkey(void *ctx_arg, const u8 *in_key,
 129                        unsigned int key_len, u32 *flags)
 130 {
 131         struct xtea_ctx *ctx = ctx_arg;
 132         const __le32 *key = (const __le32 *)in_key;
 133
 134         if (key_len != 16)
 135         {
 136                 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 137                 return -EINVAL;
 138         }
 139
 140         ctx->KEY[0] = le32_to_cpu(key[0]);
 141         ctx->KEY[1] = le32_to_cpu(key[1]);
 142         ctx->KEY[2] = le32_to_cpu(key[2]);
 143         ctx->KEY[3] = le32_to_cpu(key[3]);
 144
 145         return 0;
 146
 147 }
 148
 149 static void xtea_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
 150 {
 151         u32 y, z, sum = 0;
 152         u32 limit = XTEA_DELTA * XTEA_ROUNDS;
 153
 154         struct xtea_ctx *ctx = ctx_arg;
 155         const __le32 *in = (const __le32 *)src;
 156         __le32 *out = (__le32 *)dst;
 157
 158         y = le32_to_cpu(in[0]);
 159         z = le32_to_cpu(in[1]);
 160
 161         while (sum != limit) {
 162                 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
 163                 sum += XTEA_DELTA;
 164                 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
 165         }
 166
 167         out[0] = cpu_to_le32(y);
 168         out[1] = cpu_to_le32(z);
 169 }
 170
 171 static void xtea_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
 172 {
 173         u32 y, z, sum;
 174         struct tea_ctx *ctx = ctx_arg;
 175         const __le32 *in = (const __le32 *)src;
 176         __le32 *out = (__le32 *)dst;
 177
 178         y = le32_to_cpu(in[0]);
 179         z = le32_to_cpu(in[1]);
 180
 181         sum = XTEA_DELTA * XTEA_ROUNDS;
 182
 183         while (sum) {
 184                 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
 185                 sum -= XTEA_DELTA;
 186                 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
 187         }
 188
 189         out[0] = cpu_to_le32(y);
 190         out[1] = cpu_to_le32(z);
 191 }
 192
 193
 194 static void xeta_encrypt(void *ctx_arg, u8 *dst, const u8 *src)
 195 {
 196         u32 y, z, sum = 0;
 197         u32 limit = XTEA_DELTA * XTEA_ROUNDS;
 198
 199         struct xtea_ctx *ctx = ctx_arg;
 200         const __le32 *in = (const __le32 *)src;
 201         __le32 *out = (__le32 *)dst;
 202
 203         y = le32_to_cpu(in[0]);
 204         z = le32_to_cpu(in[1]);
 205
 206         while (sum != limit) {
 207                 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
 208                 sum += XTEA_DELTA;
 209                 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
 210         }
 211
 212         out[0] = cpu_to_le32(y);
 213         out[1] = cpu_to_le32(z);
 214 }
 215
 216 static void xeta_decrypt(void *ctx_arg, u8 *dst, const u8 *src)
 217 {
 218         u32 y, z, sum;
 219         struct tea_ctx *ctx = ctx_arg;
 220         const __le32 *in = (const __le32 *)src;
 221         __le32 *out = (__le32 *)dst;
 222
 223         y = le32_to_cpu(in[0]);
 224         z = le32_to_cpu(in[1]);
 225
 226         sum = XTEA_DELTA * XTEA_ROUNDS;
 227
 228         while (sum) {
 229                 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
 230                 sum -= XTEA_DELTA;
 231                 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
 232         }
 233
 234         out[0] = cpu_to_le32(y);
 235         out[1] = cpu_to_le32(z);
 236 }
 237
 238 static struct crypto_alg tea_alg = {
 239         .cra_name               =       "tea",
 240         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 241         .cra_blocksize          =       TEA_BLOCK_SIZE,
 242         .cra_ctxsize            =       sizeof (struct tea_ctx),
 243         .cra_alignmask          =       3,
 244         .cra_module             =       THIS_MODULE,
 245         .cra_list               =       LIST_HEAD_INIT(tea_alg.cra_list),
 246         .cra_u                  =       { .cipher = {
 247         .cia_min_keysize        =       TEA_KEY_SIZE,
 248         .cia_max_keysize        =       TEA_KEY_SIZE,
 249         .cia_setkey             =       tea_setkey,
 250         .cia_encrypt            =       tea_encrypt,
 251         .cia_decrypt            =       tea_decrypt } }
 252 };
 253
 254 static struct crypto_alg xtea_alg = {
 255         .cra_name               =       "xtea",
 256         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 257         .cra_blocksize          =       XTEA_BLOCK_SIZE,
 258         .cra_ctxsize            =       sizeof (struct xtea_ctx),
 259         .cra_alignmask          =       3,
 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            =       xtea_encrypt,
 267         .cia_decrypt            =       xtea_decrypt } }
 268 };
 269
 270 static struct crypto_alg xeta_alg = {
 271         .cra_name               =       "xeta",
 272         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 273         .cra_blocksize          =       XTEA_BLOCK_SIZE,
 274         .cra_ctxsize            =       sizeof (struct xtea_ctx),
 275         .cra_alignmask          =       3,
 276         .cra_module             =       THIS_MODULE,
 277         .cra_list               =       LIST_HEAD_INIT(xtea_alg.cra_list),
 278         .cra_u                  =       { .cipher = {
 279         .cia_min_keysize        =       XTEA_KEY_SIZE,
 280         .cia_max_keysize        =       XTEA_KEY_SIZE,
 281         .cia_setkey             =       xtea_setkey,
 282         .cia_encrypt            =       xeta_encrypt,
 283         .cia_decrypt            =       xeta_decrypt } }
 284 };
 285
 286 static int __init init(void)
 287 {
 288         int ret = 0;
 289
 290         ret = crypto_register_alg(&tea_alg);
 291         if (ret < 0)
 292                 goto out;
 293
 294         ret = crypto_register_alg(&xtea_alg);
 295         if (ret < 0) {
 296                 crypto_unregister_alg(&tea_alg);
 297                 goto out;
 298         }
 299
 300         ret = crypto_register_alg(&xeta_alg);
 301         if (ret < 0) {
 302                 crypto_unregister_alg(&tea_alg);
 303                 crypto_unregister_alg(&xtea_alg);
 304                 goto out;
 305         }
 306
 307 out:
 308         return ret;
 309 }
 310
 311 static void __exit fini(void)
 312 {
 313         crypto_unregister_alg(&tea_alg);
 314         crypto_unregister_alg(&xtea_alg);
 315         crypto_unregister_alg(&xeta_alg);
 316 }
 317
 318 MODULE_ALIAS("xtea");
 319 MODULE_ALIAS("xeta");
 320
 321 module_init(init);
 322 module_exit(fini);
 323
 324 MODULE_LICENSE("GPL");
 325 MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");