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