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, u32 *flags)
  50 {
  51         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
  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(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  70 {
  71         u32 y, z, n, sum = 0;
  72         u32 k0, k1, k2, k3;
  73         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
  74         const __le32 *in = (const __le32 *)src;
  75         __le32 *out = (__le32 *)dst;
  76
  77         y = le32_to_cpu(in[0]);
  78         z = le32_to_cpu(in[1]);
  79
  80         k0 = ctx->KEY[0];
  81         k1 = ctx->KEY[1];
  82         k2 = ctx->KEY[2];
  83         k3 = ctx->KEY[3];
  84
  85         n = TEA_ROUNDS;
  86
  87         while (n-- > 0) {
  88                 sum += TEA_DELTA;
  89                 y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
  90                 z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
  91         }
  92
  93         out[0] = cpu_to_le32(y);
  94         out[1] = cpu_to_le32(z);
  95 }
  96
  97 static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
  98 {
  99         u32 y, z, n, sum;
 100         u32 k0, k1, k2, k3;
 101         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
 102         const __le32 *in = (const __le32 *)src;
 103         __le32 *out = (__le32 *)dst;
 104
 105         y = le32_to_cpu(in[0]);
 106         z = le32_to_cpu(in[1]);
 107
 108         k0 = ctx->KEY[0];
 109         k1 = ctx->KEY[1];
 110         k2 = ctx->KEY[2];
 111         k3 = ctx->KEY[3];
 112
 113         sum = TEA_DELTA << 5;
 114
 115         n = TEA_ROUNDS;
 116
 117         while (n-- > 0) {
 118                 z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3);
 119                 y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1);
 120                 sum -= TEA_DELTA;
 121         }
 122
 123         out[0] = cpu_to_le32(y);
 124         out[1] = cpu_to_le32(z);
 125 }
 126
 127 static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key,
 128                        unsigned int key_len, u32 *flags)
 129 {
 130         struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
 131         const __le32 *key = (const __le32 *)in_key;
 132
 133         if (key_len != 16)
 134         {
 135                 *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
 136                 return -EINVAL;
 137         }
 138
 139         ctx->KEY[0] = le32_to_cpu(key[0]);
 140         ctx->KEY[1] = le32_to_cpu(key[1]);
 141         ctx->KEY[2] = le32_to_cpu(key[2]);
 142         ctx->KEY[3] = le32_to_cpu(key[3]);
 143
 144         return 0;
 145
 146 }
 147
 148 static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 149 {
 150         u32 y, z, sum = 0;
 151         u32 limit = XTEA_DELTA * XTEA_ROUNDS;
 152         struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
 153         const __le32 *in = (const __le32 *)src;
 154         __le32 *out = (__le32 *)dst;
 155
 156         y = le32_to_cpu(in[0]);
 157         z = le32_to_cpu(in[1]);
 158
 159         while (sum != limit) {
 160                 y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]);
 161                 sum += XTEA_DELTA;
 162                 z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]);
 163         }
 164
 165         out[0] = cpu_to_le32(y);
 166         out[1] = cpu_to_le32(z);
 167 }
 168
 169 static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 170 {
 171         u32 y, z, sum;
 172         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
 173         const __le32 *in = (const __le32 *)src;
 174         __le32 *out = (__le32 *)dst;
 175
 176         y = le32_to_cpu(in[0]);
 177         z = le32_to_cpu(in[1]);
 178
 179         sum = XTEA_DELTA * XTEA_ROUNDS;
 180
 181         while (sum) {
 182                 z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]);
 183                 sum -= XTEA_DELTA;
 184                 y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]);
 185         }
 186
 187         out[0] = cpu_to_le32(y);
 188         out[1] = cpu_to_le32(z);
 189 }
 190
 191
 192 static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 193 {
 194         u32 y, z, sum = 0;
 195         u32 limit = XTEA_DELTA * XTEA_ROUNDS;
 196         struct xtea_ctx *ctx = crypto_tfm_ctx(tfm);
 197         const __le32 *in = (const __le32 *)src;
 198         __le32 *out = (__le32 *)dst;
 199
 200         y = le32_to_cpu(in[0]);
 201         z = le32_to_cpu(in[1]);
 202
 203         while (sum != limit) {
 204                 y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3];
 205                 sum += XTEA_DELTA;
 206                 z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3];
 207         }
 208
 209         out[0] = cpu_to_le32(y);
 210         out[1] = cpu_to_le32(z);
 211 }
 212
 213 static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src)
 214 {
 215         u32 y, z, sum;
 216         struct tea_ctx *ctx = crypto_tfm_ctx(tfm);
 217         const __le32 *in = (const __le32 *)src;
 218         __le32 *out = (__le32 *)dst;
 219
 220         y = le32_to_cpu(in[0]);
 221         z = le32_to_cpu(in[1]);
 222
 223         sum = XTEA_DELTA * XTEA_ROUNDS;
 224
 225         while (sum) {
 226                 z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3];
 227                 sum -= XTEA_DELTA;
 228                 y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3];
 229         }
 230
 231         out[0] = cpu_to_le32(y);
 232         out[1] = cpu_to_le32(z);
 233 }
 234
 235 static struct crypto_alg tea_alg = {
 236         .cra_name               =       "tea",
 237         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 238         .cra_blocksize          =       TEA_BLOCK_SIZE,
 239         .cra_ctxsize            =       sizeof (struct tea_ctx),
 240         .cra_alignmask          =       3,
 241         .cra_module             =       THIS_MODULE,
 242         .cra_list               =       LIST_HEAD_INIT(tea_alg.cra_list),
 243         .cra_u                  =       { .cipher = {
 244         .cia_min_keysize        =       TEA_KEY_SIZE,
 245         .cia_max_keysize        =       TEA_KEY_SIZE,
 246         .cia_setkey             =       tea_setkey,
 247         .cia_encrypt            =       tea_encrypt,
 248         .cia_decrypt            =       tea_decrypt } }
 249 };
 250
 251 static struct crypto_alg xtea_alg = {
 252         .cra_name               =       "xtea",
 253         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 254         .cra_blocksize          =       XTEA_BLOCK_SIZE,
 255         .cra_ctxsize            =       sizeof (struct xtea_ctx),
 256         .cra_alignmask          =       3,
 257         .cra_module             =       THIS_MODULE,
 258         .cra_list               =       LIST_HEAD_INIT(xtea_alg.cra_list),
 259         .cra_u                  =       { .cipher = {
 260         .cia_min_keysize        =       XTEA_KEY_SIZE,
 261         .cia_max_keysize        =       XTEA_KEY_SIZE,
 262         .cia_setkey             =       xtea_setkey,
 263         .cia_encrypt            =       xtea_encrypt,
 264         .cia_decrypt            =       xtea_decrypt } }
 265 };
 266
 267 static struct crypto_alg xeta_alg = {
 268         .cra_name               =       "xeta",
 269         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
 270         .cra_blocksize          =       XTEA_BLOCK_SIZE,
 271         .cra_ctxsize            =       sizeof (struct xtea_ctx),
 272         .cra_alignmask          =       3,
 273         .cra_module             =       THIS_MODULE,
 274         .cra_list               =       LIST_HEAD_INIT(xtea_alg.cra_list),
 275         .cra_u                  =       { .cipher = {
 276         .cia_min_keysize        =       XTEA_KEY_SIZE,
 277         .cia_max_keysize        =       XTEA_KEY_SIZE,
 278         .cia_setkey             =       xtea_setkey,
 279         .cia_encrypt            =       xeta_encrypt,
 280         .cia_decrypt            =       xeta_decrypt } }
 281 };
 282
 283 static int __init init(void)
 284 {
 285         int ret = 0;
 286
 287         ret = crypto_register_alg(&tea_alg);
 288         if (ret < 0)
 289                 goto out;
 290
 291         ret = crypto_register_alg(&xtea_alg);
 292         if (ret < 0) {
 293                 crypto_unregister_alg(&tea_alg);
 294                 goto out;
 295         }
 296
 297         ret = crypto_register_alg(&xeta_alg);
 298         if (ret < 0) {
 299                 crypto_unregister_alg(&tea_alg);
 300                 crypto_unregister_alg(&xtea_alg);
 301                 goto out;
 302         }
 303
 304 out:
 305         return ret;
 306 }
 307
 308 static void __exit fini(void)
 309 {
 310         crypto_unregister_alg(&tea_alg);
 311         crypto_unregister_alg(&xtea_alg);
 312         crypto_unregister_alg(&xeta_alg);
 313 }
 314
 315 MODULE_ALIAS("xtea");
 316 MODULE_ALIAS("xeta");
 317
 318 module_init(init);
 319 module_exit(fini);
 320
 321 MODULE_LICENSE("GPL");
 322 MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");