Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

310 lines (252 sloc) 7.253 kb
/*
* 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_alg = {
.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_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_alignmask = 3,
.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_alignmask = 3,
.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 tea_mod_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 tea_mod_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(tea_mod_init);
module_exit(tea_mod_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("TEA, XTEA & XETA Cryptographic Algorithms");
Jump to Line
Something went wrong with that request. Please try again.