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Diffstat (limited to 'crypto/speck.c')
| -rw-r--r-- | crypto/speck.c | 307 |
1 files changed, 307 insertions, 0 deletions
diff --git a/crypto/speck.c b/crypto/speck.c new file mode 100644 index 0000000..58aa9f7 --- /dev/null +++ b/crypto/speck.c @@ -0,0 +1,307 @@ +// 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"); |
