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Diffstat (limited to '')
| -rw-r--r-- | crypto/tea.c | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/crypto/tea.c b/crypto/tea.c new file mode 100644 index 000000000..b70b441c7 --- /dev/null +++ b/crypto/tea.c @@ -0,0 +1,281 @@ +/* + * 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/byteorder.h> +#include <linux/crypto.h> +#include <linux/types.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 + +struct tea_ctx { + u32 KEY[4]; +}; + +struct xtea_ctx { + u32 KEY[4]; +}; + +static int tea_setkey(struct crypto_tfm *tfm, const u8 *in_key, + unsigned int key_len) +{ + struct tea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *key = (const __le32 *)in_key; + + ctx->KEY[0] = le32_to_cpu(key[0]); + ctx->KEY[1] = le32_to_cpu(key[1]); + ctx->KEY[2] = le32_to_cpu(key[2]); + ctx->KEY[3] = le32_to_cpu(key[3]); + + return 0; + +} + +static void tea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) +{ + u32 y, z, n, sum = 0; + u32 k0, k1, k2, k3; + struct tea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *in = (const __le32 *)src; + __le32 *out = (__le32 *)dst; + + y = le32_to_cpu(in[0]); + z = le32_to_cpu(in[1]); + + 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); + } + + out[0] = cpu_to_le32(y); + out[1] = cpu_to_le32(z); +} + +static void tea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) +{ + u32 y, z, n, sum; + u32 k0, k1, k2, k3; + struct tea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *in = (const __le32 *)src; + __le32 *out = (__le32 *)dst; + + y = le32_to_cpu(in[0]); + z = le32_to_cpu(in[1]); + + 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; + } + + out[0] = cpu_to_le32(y); + out[1] = cpu_to_le32(z); +} + +static int xtea_setkey(struct crypto_tfm *tfm, const u8 *in_key, + unsigned int key_len) +{ + struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *key = (const __le32 *)in_key; + + ctx->KEY[0] = le32_to_cpu(key[0]); + ctx->KEY[1] = le32_to_cpu(key[1]); + ctx->KEY[2] = le32_to_cpu(key[2]); + ctx->KEY[3] = le32_to_cpu(key[3]); + + return 0; + +} + +static void xtea_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) +{ + u32 y, z, sum = 0; + u32 limit = XTEA_DELTA * XTEA_ROUNDS; + struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *in = (const __le32 *)src; + __le32 *out = (__le32 *)dst; + + y = le32_to_cpu(in[0]); + z = le32_to_cpu(in[1]); + + 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]); + } + + out[0] = cpu_to_le32(y); + out[1] = cpu_to_le32(z); +} + +static void xtea_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) +{ + u32 y, z, sum; + struct tea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *in = (const __le32 *)src; + __le32 *out = (__le32 *)dst; + + y = le32_to_cpu(in[0]); + z = le32_to_cpu(in[1]); + + 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]); + } + + out[0] = cpu_to_le32(y); + out[1] = cpu_to_le32(z); +} + + +static void xeta_encrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) +{ + u32 y, z, sum = 0; + u32 limit = XTEA_DELTA * XTEA_ROUNDS; + struct xtea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *in = (const __le32 *)src; + __le32 *out = (__le32 *)dst; + + y = le32_to_cpu(in[0]); + z = le32_to_cpu(in[1]); + + 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]; + } + + out[0] = cpu_to_le32(y); + out[1] = cpu_to_le32(z); +} + +static void xeta_decrypt(struct crypto_tfm *tfm, u8 *dst, const u8 *src) +{ + u32 y, z, sum; + struct tea_ctx *ctx = crypto_tfm_ctx(tfm); + const __le32 *in = (const __le32 *)src; + __le32 *out = (__le32 *)dst; + + y = le32_to_cpu(in[0]); + z = le32_to_cpu(in[1]); + + 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]; + } + + out[0] = cpu_to_le32(y); + out[1] = cpu_to_le32(z); +} + +static struct crypto_alg tea_algs[3] = { { + .cra_name = "tea", + .cra_flags = CRYPTO_ALG_TYPE_CIPHER, + .cra_blocksize = TEA_BLOCK_SIZE, + .cra_ctxsize = sizeof (struct tea_ctx), + .cra_alignmask = 3, + .cra_module = THIS_MODULE, + .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 } } +}, { + .cra_name = "xtea", + .cra_flags = CRYPTO_ALG_TYPE_CIPHER, + .cra_blocksize = XTEA_BLOCK_SIZE, + .cra_ctxsize = sizeof (struct xtea_ctx), + .cra_alignmask = 3, + .cra_module = THIS_MODULE, + .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 } } +}, { + .cra_name = "xeta", + .cra_flags = CRYPTO_ALG_TYPE_CIPHER, + .cra_blocksize = XTEA_BLOCK_SIZE, + .cra_ctxsize = sizeof (struct xtea_ctx), + .cra_alignmask = 3, + .cra_module = THIS_MODULE, + .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 tea_mod_init(void) +{ + return crypto_register_algs(tea_algs, ARRAY_SIZE(tea_algs)); +} + +static void __exit tea_mod_fini(void) +{ + crypto_unregister_algs(tea_algs, ARRAY_SIZE(tea_algs)); +} + +MODULE_ALIAS_CRYPTO("tea"); +MODULE_ALIAS_CRYPTO("xtea"); +MODULE_ALIAS_CRYPTO("xeta"); + +module_init(tea_mod_init); +module_exit(tea_mod_fini); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms"); |