[funini.com] -> [kei@sodan] -> Kernel Reading

root/crypto/tea.c

/* [<][>][^][v][top][bottom][index][help] */

DEFINITIONS

This source file includes following definitions.
  1. tea_setkey
  2. tea_encrypt
  3. tea_decrypt
  4. xtea_setkey
  5. xtea_encrypt
  6. xtea_decrypt
  7. xeta_encrypt
  8. xeta_decrypt
  9. tea_mod_init
  10. tea_mod_fini

/* 
 * 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");

/* [<][>][^][v][top][bottom][index][help] */

[funini.com] -> [kei@sodan] -> Kernel Reading