LEA is a 128-bit block cipher developed by South Korea. LEA is a Korean national standard (KS X 3246) and included in the ISO/IEC 29192-2:2019 standard (Information security - Lightweight cryptography - Part 2: Block ciphers).
The LEA algorithm is a symmetric key cipher that processes data blocks of 128-bits and has three different key lengths, each with a different number of rounds: - LEA-128: 128-bit key, 24 rounds, - LEA-192: 192-bit key, 28 rounds, and - LEA-256: 256-bit key, 32 rounds. The round function of LEA consists of 32-bit ARX(modular Addition, bitwise Rotation, and bitwise XOR) operations. - https://seed.kisa.or.kr/kisa/algorithm/EgovLeaInfo.do Signed-off-by: Dongsoo Lee <letr...@nsr.re.kr> --- crypto/Kconfig | 18 ++ crypto/Makefile | 1 + crypto/lea_generic.c | 410 +++++++++++++++++++++++++++++++++++++++++++ include/crypto/lea.h | 44 +++++ 4 files changed, 473 insertions(+) create mode 100644 crypto/lea_generic.c create mode 100644 include/crypto/lea.h diff --git a/crypto/Kconfig b/crypto/Kconfig index 70661f58ee41..83649a03baf7 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -494,6 +494,24 @@ config CRYPTO_KHAZAD See https://web.archive.org/web/20171011071731/http://www.larc.usp.br/~pbarreto/KhazadPage.html for further information. +config CRYPTO_LEA + tristate "LEA" + select CRYPTO_ALGAPI + help + LEA is a 128-bit lightweight block cipher developed by South Korea. + + LEA is the a Korean standard (KS X 3246) and is included in the + ISO/IEC 29192-2:2019 standard (Information security - Lightweight + cryptography - Part 2: Block ciphers). + + It consists of 32-bit integer addition, rotation, and XOR, which can + be performed effectively on CPUs that support 32-bit operations. + + It supports 128-bit, 192-bit, and 256-bit keys. + + See: + https://seed.kisa.or.kr/kisa/algorithm/EgovLeaInfo.do + config CRYPTO_SEED tristate "SEED" depends on CRYPTO_USER_API_ENABLE_OBSOLETE diff --git a/crypto/Makefile b/crypto/Makefile index 5ac6876f935a..6b6ab104ec82 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -154,6 +154,7 @@ obj-$(CONFIG_CRYPTO_KHAZAD) += khazad.o obj-$(CONFIG_CRYPTO_ANUBIS) += anubis.o obj-$(CONFIG_CRYPTO_SEED) += seed.o obj-$(CONFIG_CRYPTO_ARIA) += aria_generic.o +obj-$(CONFIG_CRYPTO_LEA) += lea_generic.o obj-$(CONFIG_CRYPTO_CHACHA20) += chacha_generic.o obj-$(CONFIG_CRYPTO_POLY1305) += poly1305_generic.o obj-$(CONFIG_CRYPTO_DEFLATE) += deflate.o diff --git a/crypto/lea_generic.c b/crypto/lea_generic.c new file mode 100644 index 000000000000..792db01a39e0 --- /dev/null +++ b/crypto/lea_generic.c @@ -0,0 +1,410 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Cryptographic API. + * + * The LEA Cipher Algorithm + * + * LEA is a 128-bit block cipher developed by South Korea. + * + * LEA is a Korean national standard (KS X 3246) and included in the ISO/IEC + * 29192-2:2019 standard (Information security - Lightweight cryptography - + * Part 2: Block ciphers). + * + * Copyright (c) 2023 National Security Research. + * Author: Dongsoo Lee <letr...@nsr.re.kr> + */ + +#include <asm/unaligned.h> +#include <linux/module.h> +#include <crypto/algapi.h> +#include <crypto/lea.h> + +/* + * The eight 32-bit constant values δ[8] are used in the key schedule algorithm. + * They are the first 256-bits of the fractional part of + * sqrt(766965) = sqrt("LEA") + * The actual constant is additionally left-rotated from δ, which is to make the + * key schedule more compact. + * This constant can be calculated in Python as follows: + * + * from decimal import * + * rotl32 = lambda v, i: ((v << i) ^ (v >> (32 - i))) & 0xffffffff + * getcontext().prec = 87 # >= 32 * (8 + 1) / math.log(10, 2) + * + * LEA_ord = int(''.join([str(ord(ch)) for ch in "LEA"])) #766965 + * sqrt_seq = Decimal(LEA_ord).sqrt() + * + * for i in range(8): + * sqrt_seq = (sqrt_seq % 1) * (2 ** 32) + * delta = int(sqrt_seq) #δ[i] + * lea_const = rotl32(delta, i) #actual constant + * print(hex(lea_const)) + */ +static const u32 lea_constants[8] = { + 0xc3efe9db, 0x88c4d604, 0xe789f229, 0xc6f98763, + 0x15ea49e7, 0xf0bb4158, 0x13bc8ab8, 0xe204abf2, +}; + +#define LEA_SET_RK1(V, CV, ROT1, ROT2) (V = rol32(V + rol32(CV, ROT1), ROT2)) + +#define LEA_SET_RK6(V0, V1, V2, V3, V4, V5, CV_ARR, ROT0, CV_IDX) \ + do { \ + const u32 CV_I = CV_ARR[CV_IDX]; \ + CV_ARR[CV_IDX] = rol32(CV_I, ROT0); \ + LEA_SET_RK1(V0, CV_I, 0, 1); \ + LEA_SET_RK1(V1, CV_I, 1, 3); \ + LEA_SET_RK1(V2, CV_I, 2, 6); \ + LEA_SET_RK1(V3, CV_I, 3, 11); \ + LEA_SET_RK1(V4, CV_I, 4, 13); \ + LEA_SET_RK1(V5, CV_I, 5, 17); \ + } while (0) + +#define STORE_RND_KEY6(RK, V0, V1, V2, V3, V4, V5, WAY) \ + do { \ + RK[0] = V0; \ + RK[1] = V1; \ + RK[2] = V2; \ + RK[3] = V3; \ + RK[4] = V4; \ + RK[5] = V5; \ + RK += WAY * LEA_ROUND_KEY_WIDTH; \ + } while (0) + +/** + * LEA-128 can encrypt with four 32-bit integers as a round key. But in order to + * incorporate it with the encryption function for LEA-192 and LEA-256, one + * round key consists of six 32-bit integers. + */ +static void lea128_set_key(struct crypto_lea_ctx *key, const u8 *in_key) +{ + u32 x0 = get_unaligned_le32(&in_key[4 * 0]); + u32 x1 = get_unaligned_le32(&in_key[4 * 1]); + u32 x2 = get_unaligned_le32(&in_key[4 * 2]); + u32 x4 = get_unaligned_le32(&in_key[4 * 3]); + + u32 *rk_enc = key->rk_enc; + u32 *rk_dec = + key->rk_dec + (LEA128_ROUND_CNT - 1) * LEA_ROUND_KEY_WIDTH; + u32 cv[4]; + u32 rnd; + + memcpy(cv, lea_constants, sizeof(cv)); + key->round = LEA128_ROUND_CNT; + + for (rnd = 0; rnd < LEA128_ROUND_CNT; ++rnd) { + const u32 offset = rnd % 4; + const u32 cv_i = cv[offset]; + + cv[offset] = rol32(cv_i, 4); + LEA_SET_RK1(x0, cv_i, 0, 1); + LEA_SET_RK1(x1, cv_i, 1, 3); + LEA_SET_RK1(x2, cv_i, 2, 6); + LEA_SET_RK1(x4, cv_i, 3, 11); + + STORE_RND_KEY6(rk_enc, x0, x1, x2, x1, x4, x1, 1); + STORE_RND_KEY6(rk_dec, x0, x1, x2 ^ x1, x1, x4 ^ x1, x1, -1); + } +} + +/** + * The key schedule for LEA-192 can be represented as follows, + * regarding the round key as an array of 32-bit integers. + * + * T[0:6] = K[0:6] + * for i in range(28): + * T[0] = rotl32(T[0] + rotl32(delta[i % 6], i + 0), 1) + * T[1] = rotl32(T[1] + rotl32(delta[i % 6], i + 1), 3) + * T[2] = rotl32(T[2] + rotl32(delta[i % 6], i + 2), 6) + * T[3] = rotl32(T[3] + rotl32(delta[i % 6], i + 3), 11) + * T[4] = rotl32(T[4] + rotl32(delta[i % 6], i + 4), 13) + * T[5] = rotl32(T[5] + rotl32(delta[i % 6], i + 5), 17) + * RK[i*6:(i+1)*6] = T + * + * The key schedules of the LEA-128 and LEA-256 can be understood as variations + * of this calculation. + * The constants have already been left-rotated, so rotl32 of delta is + * simplified in each iteration. + */ +static void lea192_set_key(struct crypto_lea_ctx *key, const u8 *in_key) +{ + u32 x0 = get_unaligned_le32(&in_key[4 * 0]); + u32 x1 = get_unaligned_le32(&in_key[4 * 1]); + u32 x2 = get_unaligned_le32(&in_key[4 * 2]); + u32 x3 = get_unaligned_le32(&in_key[4 * 3]); + u32 x4 = get_unaligned_le32(&in_key[4 * 4]); + u32 x5 = get_unaligned_le32(&in_key[4 * 5]); + + u32 *rk_enc = key->rk_enc; + u32 *rk_dec = + key->rk_dec + (LEA192_ROUND_CNT - 1) * LEA_ROUND_KEY_WIDTH; + u32 cv[6]; + u32 rnd; + + memcpy(cv, lea_constants, sizeof(cv)); + key->round = LEA192_ROUND_CNT; + + for (rnd = 0; rnd < LEA192_ROUND_CNT; ++rnd) { + const u32 offset = rnd % 6; + + LEA_SET_RK6(x0, x1, x2, x3, x4, x5, cv, 6, offset); + STORE_RND_KEY6(rk_enc, x0, x1, x2, x3, x4, x5, 1); + STORE_RND_KEY6(rk_dec, x0, x1, x2 ^ x1, x3, x4 ^ x3, x5, -1); + } +} + +/** + * In the LEA-256, the encryption key is eight 32-bit integers, which does not + * match LEA's round key width of 6. Therefore, partial loop unrolling is used + * to compute 4 round keys per loop. + */ +static void lea256_set_key(struct crypto_lea_ctx *key, const u8 *in_key) +{ + u32 x0 = get_unaligned_le32(&in_key[4 * 0]); + u32 x1 = get_unaligned_le32(&in_key[4 * 1]); + u32 x2 = get_unaligned_le32(&in_key[4 * 2]); + u32 x3 = get_unaligned_le32(&in_key[4 * 3]); + u32 x4 = get_unaligned_le32(&in_key[4 * 4]); + u32 x5 = get_unaligned_le32(&in_key[4 * 5]); + u32 x6 = get_unaligned_le32(&in_key[4 * 6]); + u32 x7 = get_unaligned_le32(&in_key[4 * 7]); + + u32 *rk_enc = key->rk_enc; + u32 *rk_dec = + key->rk_dec + (LEA256_ROUND_CNT - 1) * LEA_ROUND_KEY_WIDTH; + u32 cv[8]; + u32 rnd; + + memcpy(cv, lea_constants, sizeof(cv)); + key->round = LEA256_ROUND_CNT; + + for (rnd = 0; rnd < LEA256_ROUND_CNT; rnd += 4) { + u32 offset = rnd % 8; + + LEA_SET_RK6(x0, x1, x2, x3, x4, x5, cv, 8, offset); + STORE_RND_KEY6(rk_enc, x0, x1, x2, x3, x4, x5, 1); + STORE_RND_KEY6(rk_dec, x0, x1, x2 ^ x1, x3, x4 ^ x3, x5, -1); + + ++offset; + LEA_SET_RK6(x6, x7, x0, x1, x2, x3, cv, 8, offset); + STORE_RND_KEY6(rk_enc, x6, x7, x0, x1, x2, x3, 1); + STORE_RND_KEY6(rk_dec, x6, x7, x0 ^ x7, x1, x2 ^ x1, x3, -1); + + ++offset; + LEA_SET_RK6(x4, x5, x6, x7, x0, x1, cv, 8, offset); + STORE_RND_KEY6(rk_enc, x4, x5, x6, x7, x0, x1, 1); + STORE_RND_KEY6(rk_dec, x4, x5, x6 ^ x5, x7, x0 ^ x7, x1, -1); + + ++offset; + LEA_SET_RK6(x2, x3, x4, x5, x6, x7, cv, 8, offset); + STORE_RND_KEY6(rk_enc, x2, x3, x4, x5, x6, x7, 1); + STORE_RND_KEY6(rk_dec, x2, x3, x4 ^ x3, x5, x6 ^ x5, x7, -1); + } +} + +int lea_set_key(struct crypto_lea_ctx *key, const u8 *in_key, u32 key_len) +{ + switch (key_len) { + case 16: + lea128_set_key(key, in_key); + return 0; + case 24: + lea192_set_key(key, in_key); + return 0; + case 32: + lea256_set_key(key, in_key); + return 0; + } + + return -EINVAL; +} +EXPORT_SYMBOL_GPL(lea_set_key); + +/** + * The encryption round function can be represented as follows + * + * next_v3 = v0 + * next_v2 = rotr32((v2 ^ RK[4]) + (v3 ^ RK[5]), 3); + * next_v1 = rotr32((v1 ^ RK[2]) + (v2 ^ RK[3]), 5); + * next_v0 = rotl32((v0 ^ RK[0]) + (v1 ^ RK[1]), 9); + * + * It is possible to avoid shuffling by partial unrolling, which unrolls 4 + * rounds in a loop. + */ +#define LEA_ENC_RND(V0, V1, V2, V3, RK) \ + do { \ + V3 = ror32((V2 ^ RK[4]) + (V3 ^ RK[5]), 3); \ + V2 = ror32((V1 ^ RK[2]) + (V2 ^ RK[3]), 5); \ + V1 = rol32((V0 ^ RK[0]) + (V1 ^ RK[1]), 9); \ + RK += LEA_ROUND_KEY_WIDTH; \ + } while (0) + +void lea_encrypt(const struct crypto_lea_ctx *key, u8 *out, const u8 *in) +{ + u32 x0 = get_unaligned_le32(&in[4 * 0]); + u32 x1 = get_unaligned_le32(&in[4 * 1]); + u32 x2 = get_unaligned_le32(&in[4 * 2]); + u32 x3 = get_unaligned_le32(&in[4 * 3]); + + const u32 *rk = key->rk_enc; + const u32 *rk_tail = rk + LEA_ROUND_KEY_WIDTH * key->round; + + while (rk < rk_tail) { + LEA_ENC_RND(x0, x1, x2, x3, rk); + LEA_ENC_RND(x1, x2, x3, x0, rk); + LEA_ENC_RND(x2, x3, x0, x1, rk); + LEA_ENC_RND(x3, x0, x1, x2, rk); + } + + put_unaligned_le32(x0, &out[4 * 0]); + put_unaligned_le32(x1, &out[4 * 1]); + put_unaligned_le32(x2, &out[4 * 2]); + put_unaligned_le32(x3, &out[4 * 3]); +} +EXPORT_SYMBOL_GPL(lea_encrypt); + +/** + * The decryption round function for LEA is the inverse of encryption, + * so it can be represented as follows + * + * next_v0 = v3 + * next_v1 = (rotr32(v0, 9) - (next_v0 ^ RK[0])) ^ RK[1]; + * next_v2 = (rotl32(v1, 5) - (next_v1 ^ RK[2])) ^ RK[3]; + * next_v3 = (rotl32(v2, 3) - (next_v2 ^ RK[4])) ^ RK[5]; + * + * However, in the above expression, all previous steps must be computed to + * calculate next_v3. + * If the process is unpacked, the computation would look like this + * + * next_v0 = v3 + * next_v1 = (rotr32(v0, 9) - (v3 ^ RK[0])) ^ RK[1]; + * next_v2 = (rotl32(v1, 5) - ((rotr32(v0, 9) - (v3 ^ RK[0])) ^ RK[1] ^ RK[2])) + * ^ RK[3]; + * next_v3 = (rotl32(v2, 3) - ((rotl32(v1, 5) + * - ((rotr32(v0, 9) - (v3 ^ RK[0])) ^ RK[1] ^ RK[2])) + * ^ RK[3] ^ RK[4])) ^ RK[5]; + * + * Letting (rotr32(v0, 9) - (v3 ^ RK[0])) be the intermediate value, + * it would look like + * + * next_v0 = v3 + * tmp_v1 = (rotr32(v0, 9) - (v3 ^ RK[0])) + * next_v1 = tmp_v1 ^ RK[1]; + * next_v2 = (rotl32(v1, 5) - (tmp_v1 ^ RK[1] ^ RK[2])) ^ RK[3]; + * next_v3 = (rotl32(v2, 3) - ((rotl32(V1, 5) - (tmp_v1 ^ RK[1] ^ RK[2])) + * ^ RK[3] ^ RK[4])) ^ RK[5]; + * + * Similarly, letting (rotl32(v1, 5) - (tmp_v1 ^ RK[1] ^ RK[2])) be the + * intermediate value, it would look like this + * + * next_v0 = v3 + * tmp_v1 = (rotr32(v0, 9) - (v3 ^ RK[0])) + * next_v1 = tmp_v1 ^ RK[1]; + * tmp_v2 = (rotl32(v1, 5) - (tmp_v1 ^ RK[1] ^ RK[2])) + * next_v2 = tmp_v2 ^ RK[3]; + * next_v3 = (rotl32(v2, 3) - (tmp_v2 ^ RK[3] ^ RK[4])) ^ RK[5]; + * + * To reduce the operation of XORing RK twice to once, try using + * RKdec[0] = RK[0], RKdec[1] = RK[1], RKdec[2] = RK[1] ^ RK[2] + * RKdec[3] = RK[3], RKdec[4] = RK[3] ^ RK[4], RKdec[5] = RK[5] + * + * then the code can be rewritten as follows + * + * next_v0 = v3 + * tmp_v1 = (rotr32(v0, 9) - (v3 ^ RKdec[0])); + * next_v1 = tmp_v1 ^ RKdec[1]; + * tmp_v2 = (rotl32(v1, 5) - (tmp_v1 ^ RKdec[2]); + * next_v2 = tmp_v2 ^ RKdec[3]; + * next_v3 = (rotl32(v2, 3) - (tmp_v2 ^ RKdec[4]) ^ RKdec[5]; + * + * There is no difference in the number of operations, but there is two less + * data-dependent step, some operations can be performed simultaneously in the + * out-of-order processor. + */ +#define LEA_DEC_RND(V0, V1, V2, V3, TMP, RK) \ + do { \ + TMP = (ror32(V0, 9) - (V3 ^ RK[0])); \ + V0 = TMP ^ RK[1]; \ + TMP = (rol32(V1, 5) - (TMP ^ RK[2])); \ + V1 = TMP ^ RK[3]; \ + V2 = (rol32(V2, 3) - (TMP ^ RK[4])) ^ RK[5]; \ + RK += LEA_ROUND_KEY_WIDTH; \ + } while (0) + +void lea_decrypt(const struct crypto_lea_ctx *key, u8 *out, const u8 *in) +{ + const u32 *rk = key->rk_dec; + const u32 *rk_tail = rk + LEA_ROUND_KEY_WIDTH * key->round; + + u32 x0 = get_unaligned_le32(&in[4 * 0]); + u32 x1 = get_unaligned_le32(&in[4 * 1]); + u32 x2 = get_unaligned_le32(&in[4 * 2]); + u32 x3 = get_unaligned_le32(&in[4 * 3]); + u32 tmp; + + while (rk < rk_tail) { + LEA_DEC_RND(x0, x1, x2, x3, tmp, rk); + LEA_DEC_RND(x3, x0, x1, x2, tmp, rk); + LEA_DEC_RND(x2, x3, x0, x1, tmp, rk); + LEA_DEC_RND(x1, x2, x3, x0, tmp, rk); + }; + + put_unaligned_le32(x0, &out[4 * 0]); + put_unaligned_le32(x1, &out[4 * 1]); + put_unaligned_le32(x2, &out[4 * 2]); + put_unaligned_le32(x3, &out[4 * 3]); +} +EXPORT_SYMBOL_GPL(lea_decrypt); + +static int crypto_lea_set_key(struct crypto_tfm *tfm, const u8 *in_key, + u32 key_len) +{ + return lea_set_key(crypto_tfm_ctx(tfm), in_key, key_len); +} + +static void crypto_lea_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) +{ + const struct crypto_lea_ctx *key = crypto_tfm_ctx(tfm); + + lea_encrypt(key, out, in); +} + +static void crypto_lea_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in) +{ + const struct crypto_lea_ctx *key = crypto_tfm_ctx(tfm); + + lea_decrypt(key, out, in); +} + +static struct crypto_alg lea_alg = { + .cra_name = "lea", + .cra_driver_name = "lea-generic", + .cra_priority = 100, + .cra_flags = CRYPTO_ALG_TYPE_CIPHER, + .cra_blocksize = LEA_BLOCK_SIZE, + .cra_ctxsize = sizeof(struct crypto_lea_ctx), + .cra_module = THIS_MODULE, + .cra_u = { .cipher = { .cia_min_keysize = LEA_MIN_KEY_SIZE, + .cia_max_keysize = LEA_MAX_KEY_SIZE, + .cia_setkey = crypto_lea_set_key, + .cia_encrypt = crypto_lea_encrypt, + .cia_decrypt = crypto_lea_decrypt } } +}; + +static int crypto_lea_init(void) +{ + return crypto_register_alg(&lea_alg); +} + +static void crypto_lea_exit(void) +{ + crypto_unregister_alg(&lea_alg); +} + +module_init(crypto_lea_init); +module_exit(crypto_lea_exit); + +MODULE_DESCRIPTION("LEA Cipher Algorithm"); +MODULE_AUTHOR("Dongsoo Lee <letr...@nsr.re.kr>"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_CRYPTO("lea"); +MODULE_ALIAS_CRYPTO("lea-generic"); diff --git a/include/crypto/lea.h b/include/crypto/lea.h new file mode 100644 index 000000000000..ce134fa98908 --- /dev/null +++ b/include/crypto/lea.h @@ -0,0 +1,44 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Cryptographic API. + * + * The LEA Cipher Algorithm + * + * LEA is a 128-bit block cipher developed by South Korea. + * + * LEA is a Korean national standard (KS X 3246) and included in the ISO/IEC + * 29192-2:2019 standard (Information security - Lightweight cryptography - + * Part 2: Block ciphers). + * + * Copyright (c) 2023 National Security Research. + * Author: Dongsoo Lee <letr...@nsr.re.kr> + */ + +#ifndef _CRYPTO_LEA_H +#define _CRYPTO_LEA_H + +#include <linux/types.h> + +#define LEA_MIN_KEY_SIZE 16 +#define LEA_MAX_KEY_SIZE 32 +#define LEA_BLOCK_SIZE 16 +#define LEA_ROUND_KEY_WIDTH 6 + +#define LEA128_ROUND_CNT 24 +#define LEA192_ROUND_CNT 28 +#define LEA256_ROUND_CNT 32 + +#define LEA_MAX_KEYLENGTH_U32 (LEA256_ROUND_CNT * LEA_ROUND_KEY_WIDTH) +#define LEA_MAX_KEYLENGTH (LEA_MAX_KEYLENGTH_U32 * sizeof(u32)) + +struct crypto_lea_ctx { + u32 rk_enc[LEA_MAX_KEYLENGTH_U32]; + u32 rk_dec[LEA_MAX_KEYLENGTH_U32]; + u32 round; +}; + +int lea_set_key(struct crypto_lea_ctx *key, const u8 *in_key, u32 key_len); +void lea_encrypt(const struct crypto_lea_ctx *key, u8 *out, const u8 *in); +void lea_decrypt(const struct crypto_lea_ctx *key, u8 *out, const u8 *in); + +#endif -- 2.40.1
