linux/crypto/speck.c

308 lines
7.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Speck: a lightweight block cipher
*
* Copyright (c) 2018 Google, Inc
*
* Speck has 10 variants, including 5 block sizes. For now we only implement
* the variants Speck128/128, Speck128/192, Speck128/256, Speck64/96, and
* Speck64/128. Speck${B}/${K} denotes the variant with a block size of B bits
* and a key size of K bits. The Speck128 variants are believed to be the most
* secure variants, and they use the same block size and key sizes as AES. The
* Speck64 variants are less secure, but on 32-bit processors are usually
* faster. The remaining variants (Speck32, Speck48, and Speck96) are even less
* secure and/or not as well suited for implementation on either 32-bit or
* 64-bit processors, so are omitted.
*
* Reference: "The Simon and Speck Families of Lightweight Block Ciphers"
* https://eprint.iacr.org/2013/404.pdf
*
* In a correspondence, the Speck designers have also clarified that the words
* should be interpreted in little-endian format, and the words should be
* ordered such that the first word of each block is 'y' rather than 'x', and
* the first key word (rather than the last) becomes the first round key.
*/
#include <asm/unaligned.h>
#include <crypto/speck.h>
#include <linux/bitops.h>
#include <linux/crypto.h>
#include <linux/init.h>
#include <linux/module.h>
/* Speck128 */
static __always_inline void speck128_round(u64 *x, u64 *y, u64 k)
{
*x = ror64(*x, 8);
*x += *y;
*x ^= k;
*y = rol64(*y, 3);
*y ^= *x;
}
static __always_inline void speck128_unround(u64 *x, u64 *y, u64 k)
{
*y ^= *x;
*y = ror64(*y, 3);
*x ^= k;
*x -= *y;
*x = rol64(*x, 8);
}
void crypto_speck128_encrypt(const struct speck128_tfm_ctx *ctx,
u8 *out, const u8 *in)
{
u64 y = get_unaligned_le64(in);
u64 x = get_unaligned_le64(in + 8);
int i;
for (i = 0; i < ctx->nrounds; i++)
speck128_round(&x, &y, ctx->round_keys[i]);
put_unaligned_le64(y, out);
put_unaligned_le64(x, out + 8);
}
EXPORT_SYMBOL_GPL(crypto_speck128_encrypt);
static void speck128_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
crypto_speck128_encrypt(crypto_tfm_ctx(tfm), out, in);
}
void crypto_speck128_decrypt(const struct speck128_tfm_ctx *ctx,
u8 *out, const u8 *in)
{
u64 y = get_unaligned_le64(in);
u64 x = get_unaligned_le64(in + 8);
int i;
for (i = ctx->nrounds - 1; i >= 0; i--)
speck128_unround(&x, &y, ctx->round_keys[i]);
put_unaligned_le64(y, out);
put_unaligned_le64(x, out + 8);
}
EXPORT_SYMBOL_GPL(crypto_speck128_decrypt);
static void speck128_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
crypto_speck128_decrypt(crypto_tfm_ctx(tfm), out, in);
}
int crypto_speck128_setkey(struct speck128_tfm_ctx *ctx, const u8 *key,
unsigned int keylen)
{
u64 l[3];
u64 k;
int i;
switch (keylen) {
case SPECK128_128_KEY_SIZE:
k = get_unaligned_le64(key);
l[0] = get_unaligned_le64(key + 8);
ctx->nrounds = SPECK128_128_NROUNDS;
for (i = 0; i < ctx->nrounds; i++) {
ctx->round_keys[i] = k;
speck128_round(&l[0], &k, i);
}
break;
case SPECK128_192_KEY_SIZE:
k = get_unaligned_le64(key);
l[0] = get_unaligned_le64(key + 8);
l[1] = get_unaligned_le64(key + 16);
ctx->nrounds = SPECK128_192_NROUNDS;
for (i = 0; i < ctx->nrounds; i++) {
ctx->round_keys[i] = k;
speck128_round(&l[i % 2], &k, i);
}
break;
case SPECK128_256_KEY_SIZE:
k = get_unaligned_le64(key);
l[0] = get_unaligned_le64(key + 8);
l[1] = get_unaligned_le64(key + 16);
l[2] = get_unaligned_le64(key + 24);
ctx->nrounds = SPECK128_256_NROUNDS;
for (i = 0; i < ctx->nrounds; i++) {
ctx->round_keys[i] = k;
speck128_round(&l[i % 3], &k, i);
}
break;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(crypto_speck128_setkey);
static int speck128_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
return crypto_speck128_setkey(crypto_tfm_ctx(tfm), key, keylen);
}
/* Speck64 */
static __always_inline void speck64_round(u32 *x, u32 *y, u32 k)
{
*x = ror32(*x, 8);
*x += *y;
*x ^= k;
*y = rol32(*y, 3);
*y ^= *x;
}
static __always_inline void speck64_unround(u32 *x, u32 *y, u32 k)
{
*y ^= *x;
*y = ror32(*y, 3);
*x ^= k;
*x -= *y;
*x = rol32(*x, 8);
}
void crypto_speck64_encrypt(const struct speck64_tfm_ctx *ctx,
u8 *out, const u8 *in)
{
u32 y = get_unaligned_le32(in);
u32 x = get_unaligned_le32(in + 4);
int i;
for (i = 0; i < ctx->nrounds; i++)
speck64_round(&x, &y, ctx->round_keys[i]);
put_unaligned_le32(y, out);
put_unaligned_le32(x, out + 4);
}
EXPORT_SYMBOL_GPL(crypto_speck64_encrypt);
static void speck64_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
crypto_speck64_encrypt(crypto_tfm_ctx(tfm), out, in);
}
void crypto_speck64_decrypt(const struct speck64_tfm_ctx *ctx,
u8 *out, const u8 *in)
{
u32 y = get_unaligned_le32(in);
u32 x = get_unaligned_le32(in + 4);
int i;
for (i = ctx->nrounds - 1; i >= 0; i--)
speck64_unround(&x, &y, ctx->round_keys[i]);
put_unaligned_le32(y, out);
put_unaligned_le32(x, out + 4);
}
EXPORT_SYMBOL_GPL(crypto_speck64_decrypt);
static void speck64_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
crypto_speck64_decrypt(crypto_tfm_ctx(tfm), out, in);
}
int crypto_speck64_setkey(struct speck64_tfm_ctx *ctx, const u8 *key,
unsigned int keylen)
{
u32 l[3];
u32 k;
int i;
switch (keylen) {
case SPECK64_96_KEY_SIZE:
k = get_unaligned_le32(key);
l[0] = get_unaligned_le32(key + 4);
l[1] = get_unaligned_le32(key + 8);
ctx->nrounds = SPECK64_96_NROUNDS;
for (i = 0; i < ctx->nrounds; i++) {
ctx->round_keys[i] = k;
speck64_round(&l[i % 2], &k, i);
}
break;
case SPECK64_128_KEY_SIZE:
k = get_unaligned_le32(key);
l[0] = get_unaligned_le32(key + 4);
l[1] = get_unaligned_le32(key + 8);
l[2] = get_unaligned_le32(key + 12);
ctx->nrounds = SPECK64_128_NROUNDS;
for (i = 0; i < ctx->nrounds; i++) {
ctx->round_keys[i] = k;
speck64_round(&l[i % 3], &k, i);
}
break;
default:
return -EINVAL;
}
return 0;
}
EXPORT_SYMBOL_GPL(crypto_speck64_setkey);
static int speck64_setkey(struct crypto_tfm *tfm, const u8 *key,
unsigned int keylen)
{
return crypto_speck64_setkey(crypto_tfm_ctx(tfm), key, keylen);
}
/* Algorithm definitions */
static struct crypto_alg speck_algs[] = {
{
.cra_name = "speck128",
.cra_driver_name = "speck128-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = SPECK128_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct speck128_tfm_ctx),
.cra_module = THIS_MODULE,
.cra_u = {
.cipher = {
.cia_min_keysize = SPECK128_128_KEY_SIZE,
.cia_max_keysize = SPECK128_256_KEY_SIZE,
.cia_setkey = speck128_setkey,
.cia_encrypt = speck128_encrypt,
.cia_decrypt = speck128_decrypt
}
}
}, {
.cra_name = "speck64",
.cra_driver_name = "speck64-generic",
.cra_priority = 100,
.cra_flags = CRYPTO_ALG_TYPE_CIPHER,
.cra_blocksize = SPECK64_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct speck64_tfm_ctx),
.cra_module = THIS_MODULE,
.cra_u = {
.cipher = {
.cia_min_keysize = SPECK64_96_KEY_SIZE,
.cia_max_keysize = SPECK64_128_KEY_SIZE,
.cia_setkey = speck64_setkey,
.cia_encrypt = speck64_encrypt,
.cia_decrypt = speck64_decrypt
}
}
}
};
static int __init speck_module_init(void)
{
return crypto_register_algs(speck_algs, ARRAY_SIZE(speck_algs));
}
static void __exit speck_module_exit(void)
{
crypto_unregister_algs(speck_algs, ARRAY_SIZE(speck_algs));
}
module_init(speck_module_init);
module_exit(speck_module_exit);
MODULE_DESCRIPTION("Speck block cipher (generic)");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Eric Biggers <ebiggers@google.com>");
MODULE_ALIAS_CRYPTO("speck128");
MODULE_ALIAS_CRYPTO("speck128-generic");
MODULE_ALIAS_CRYPTO("speck64");
MODULE_ALIAS_CRYPTO("speck64-generic");