diff options
Diffstat (limited to 'crypto/tea.c')
| -rw-r--r-- | crypto/tea.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/crypto/tea.c b/crypto/tea.c new file mode 100644 index 0000000..03c23cb --- /dev/null +++ b/crypto/tea.c @@ -0,0 +1,248 @@ +/* + * Cryptographic API. + * + * TEA and Xtended TEA Algorithms + * + * The TEA and Xtended TEA algorithms were developed by David Wheeler + * and Roger Needham at the Computer Laboratory of Cambridge University. + * + * 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 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 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; + } + +out: + return ret; +} + +static void __exit fini(void) +{ + crypto_unregister_alg(&tea_alg); + crypto_unregister_alg(&xtea_alg); +} + +MODULE_ALIAS("xtea"); + +module_init(init); +module_exit(fini); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("TEA & XTEA Cryptographic Algorithms"); |