/* * Cryptographic API. * * TEA, XTEA, and XETA crypto alogrithms * * The TEA and Xtended TEA algorithms were developed by David Wheeler * and Roger Needham at the Computer Laboratory of Cambridge University. * * Due to the order of evaluation in XTEA many people have incorrectly * implemented it. XETA (XTEA in the wrong order), exists for * compatibility with these implementations. * * Copyright (c) 2004 Aaron Grothe ajgrothe@yahoo.com * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * */ #include <linux/init.h> #include <linux/module.h> #include <linux/mm.h> #include <asm/scatterlist.h> #include <linux/crypto.h> #define TEA_KEY_SIZE 16 #define TEA_BLOCK_SIZE 8 #define TEA_ROUNDS 32 #define TEA_DELTA 0x9e3779b9 #define XTEA_KEY_SIZE 16 #define XTEA_BLOCK_SIZE 8 #define XTEA_ROUNDS 32 #define XTEA_DELTA 0x9e3779b9 #define u32_in(x) le32_to_cpu(*(const __le32 *)(x)) #define u32_out(to, from) (*(__le32 *)(to) = cpu_to_le32(from)) struct tea_ctx { u32 KEY[4]; }; struct xtea_ctx { u32 KEY[4]; }; static int tea_setkey(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags) { struct tea_ctx *ctx = ctx_arg; if (key_len != 16) { *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; return -EINVAL; } ctx->KEY[0] = u32_in (in_key); ctx->KEY[1] = u32_in (in_key + 4); ctx->KEY[2] = u32_in (in_key + 8); ctx->KEY[3] = u32_in (in_key + 12); return 0; } static void tea_encrypt(void *ctx_arg, u8 *dst, const u8 *src) { u32 y, z, n, sum = 0; u32 k0, k1, k2, k3; struct tea_ctx *ctx = ctx_arg; y = u32_in (src); z = u32_in (src + 4); k0 = ctx->KEY[0]; k1 = ctx->KEY[1]; k2 = ctx->KEY[2]; k3 = ctx->KEY[3]; n = TEA_ROUNDS; while (n-- > 0) { sum += TEA_DELTA; y += ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); z += ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); } u32_out (dst, y); u32_out (dst + 4, z); } static void tea_decrypt(void *ctx_arg, u8 *dst, const u8 *src) { u32 y, z, n, sum; u32 k0, k1, k2, k3; struct tea_ctx *ctx = ctx_arg; y = u32_in (src); z = u32_in (src + 4); k0 = ctx->KEY[0]; k1 = ctx->KEY[1]; k2 = ctx->KEY[2]; k3 = ctx->KEY[3]; sum = TEA_DELTA << 5; n = TEA_ROUNDS; while (n-- > 0) { z -= ((y << 4) + k2) ^ (y + sum) ^ ((y >> 5) + k3); y -= ((z << 4) + k0) ^ (z + sum) ^ ((z >> 5) + k1); sum -= TEA_DELTA; } u32_out (dst, y); u32_out (dst + 4, z); } static int xtea_setkey(void *ctx_arg, const u8 *in_key, unsigned int key_len, u32 *flags) { struct xtea_ctx *ctx = ctx_arg; if (key_len != 16) { *flags |= CRYPTO_TFM_RES_BAD_KEY_LEN; return -EINVAL; } ctx->KEY[0] = u32_in (in_key); ctx->KEY[1] = u32_in (in_key + 4); ctx->KEY[2] = u32_in (in_key + 8); ctx->KEY[3] = u32_in (in_key + 12); return 0; } static void xtea_encrypt(void *ctx_arg, u8 *dst, const u8 *src) { u32 y, z, sum = 0; u32 limit = XTEA_DELTA * XTEA_ROUNDS; struct xtea_ctx *ctx = ctx_arg; y = u32_in (src); z = u32_in (src + 4); while (sum != limit) { y += ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum&3]); sum += XTEA_DELTA; z += ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 &3]); } u32_out (dst, y); u32_out (dst + 4, z); } static void xtea_decrypt(void *ctx_arg, u8 *dst, const u8 *src) { u32 y, z, sum; struct tea_ctx *ctx = ctx_arg; y = u32_in (src); z = u32_in (src + 4); sum = XTEA_DELTA * XTEA_ROUNDS; while (sum) { z -= ((y << 4 ^ y >> 5) + y) ^ (sum + ctx->KEY[sum>>11 & 3]); sum -= XTEA_DELTA; y -= ((z << 4 ^ z >> 5) + z) ^ (sum + ctx->KEY[sum & 3]); } u32_out (dst, y); u32_out (dst + 4, z); } static void xeta_encrypt(void *ctx_arg, u8 *dst, const u8 *src) { u32 y, z, sum = 0; u32 limit = XTEA_DELTA * XTEA_ROUNDS; struct xtea_ctx *ctx = ctx_arg; y = u32_in (src); z = u32_in (src + 4); while (sum != limit) { y += (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum&3]; sum += XTEA_DELTA; z += (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 &3]; } u32_out (dst, y); u32_out (dst + 4, z); } static void xeta_decrypt(void *ctx_arg, u8 *dst, const u8 *src) { u32 y, z, sum; struct tea_ctx *ctx = ctx_arg; y = u32_in (src); z = u32_in (src + 4); sum = XTEA_DELTA * XTEA_ROUNDS; while (sum) { z -= (y << 4 ^ y >> 5) + (y ^ sum) + ctx->KEY[sum>>11 & 3]; sum -= XTEA_DELTA; y -= (z << 4 ^ z >> 5) + (z ^ sum) + ctx->KEY[sum & 3]; } u32_out (dst, y); u32_out (dst + 4, z); } static struct crypto_alg tea_alg = { .cra_name = "tea", .cra_flags = CRYPTO_ALG_TYPE_CIPHER, .cra_blocksize = TEA_BLOCK_SIZE, .cra_ctxsize = sizeof (struct tea_ctx), .cra_module = THIS_MODULE, .cra_list = LIST_HEAD_INIT(tea_alg.cra_list), .cra_u = { .cipher = { .cia_min_keysize = TEA_KEY_SIZE, .cia_max_keysize = TEA_KEY_SIZE, .cia_setkey = tea_setkey, .cia_encrypt = tea_encrypt, .cia_decrypt = tea_decrypt } } }; static struct crypto_alg xtea_alg = { .cra_name = "xtea", .cra_flags = CRYPTO_ALG_TYPE_CIPHER, .cra_blocksize = XTEA_BLOCK_SIZE, .cra_ctxsize = sizeof (struct xtea_ctx), .cra_module = THIS_MODULE, .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list), .cra_u = { .cipher = { .cia_min_keysize = XTEA_KEY_SIZE, .cia_max_keysize = XTEA_KEY_SIZE, .cia_setkey = xtea_setkey, .cia_encrypt = xtea_encrypt, .cia_decrypt = xtea_decrypt } } }; static struct crypto_alg xeta_alg = { .cra_name = "xeta", .cra_flags = CRYPTO_ALG_TYPE_CIPHER, .cra_blocksize = XTEA_BLOCK_SIZE, .cra_ctxsize = sizeof (struct xtea_ctx), .cra_module = THIS_MODULE, .cra_list = LIST_HEAD_INIT(xtea_alg.cra_list), .cra_u = { .cipher = { .cia_min_keysize = XTEA_KEY_SIZE, .cia_max_keysize = XTEA_KEY_SIZE, .cia_setkey = xtea_setkey, .cia_encrypt = xeta_encrypt, .cia_decrypt = xeta_decrypt } } }; static int __init init(void) { int ret = 0; ret = crypto_register_alg(&tea_alg); if (ret < 0) goto out; ret = crypto_register_alg(&xtea_alg); if (ret < 0) { crypto_unregister_alg(&tea_alg); goto out; } ret = crypto_register_alg(&xeta_alg); if (ret < 0) { crypto_unregister_alg(&tea_alg); crypto_unregister_alg(&xtea_alg); goto out; } out: return ret; } static void __exit fini(void) { crypto_unregister_alg(&tea_alg); crypto_unregister_alg(&xtea_alg); crypto_unregister_alg(&xeta_alg); } MODULE_ALIAS("xtea"); MODULE_ALIAS("xeta"); module_init(init); module_exit(fini); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");