radare2/libr/crypto/p/crypto_sm4_algo.c
2024-03-16 03:03:48 +01:00

74 lines
1.8 KiB
C

/* radare - LGPL - Copyright 2017-2022 - Sylvain Pelissier */
// Implementation of SM4 block cipher https://datatracker.ietf.org/doc/html/draft-ribose-cfrg-sm4-10
#include <r_crypto.h>
#include <r_crypto/r_sm4.h>
#include <r_util.h>
#include <memory.h>
/* Permutations T */
static ut32 sm4_T(ut32 x) {
ut8 a[4];
ut8 b[4];
ut32 lb = 0;
r_write_be32 (a, x);
b[0] = sm4_sbox[a[0]];
b[1] = sm4_sbox[a[1]];
b[2] = sm4_sbox[a[2]];
b[3] = sm4_sbox[a[3]];
lb = r_read_be32 (b);
/* Linear transform L */
return lb ^ (SM4_ROTL (lb, 2)) ^ (SM4_ROTL (lb, 10)) ^ (SM4_ROTL (lb, 18)) ^ (SM4_ROTL (lb, 24));
}
/* SM4 round */
void sm4_round(const ut32 *sk, const ut8 *input, ut8 *output) {
int i;
ut32 tmp[36] = { 0 };
tmp[0] = r_read_at_be32 (input, 0);
tmp[1] = r_read_at_be32 (input, 4);
tmp[2] = r_read_at_be32 (input, 8);
tmp[3] = r_read_at_be32 (input, 12);
for (i = 0; i < 32; i++) {
/* Round F function */
tmp[i + 4] = tmp[i] ^ sm4_T (tmp[i + 1] ^ tmp[i + 2] ^ tmp[i + 3] ^ sk[i]);
}
r_write_at_be32 (output, tmp[35], 0);
r_write_at_be32 (output, tmp[34], 4);
r_write_at_be32 (output, tmp[33], 8);
r_write_at_be32 (output, tmp[32], 12);
}
/* SM4 key schedule */
bool sm4_init(ut32 *sk, const ut8 *key, int keylen, int dir) {
ut32 MK[4];
ut32 k[36];
int i = 0;
if (keylen != SM4_KEY_SIZE) {
return false;
}
MK[0] = r_read_at_be32 (key, 0);
MK[1] = r_read_at_be32 (key, 4);
MK[2] = r_read_at_be32 (key, 8);
MK[3] = r_read_at_be32 (key, 12);
k[0] = MK[0] ^ FK[0];
k[1] = MK[1] ^ FK[1];
k[2] = MK[2] ^ FK[2];
k[3] = MK[3] ^ FK[3];
for (i = 0; i < 32; i++) {
k[i + 4] = k[i] ^ (sm4_RK (k[i + 1] ^ k[i + 2] ^ k[i + 3] ^ sm4_CK[i]));
if (dir == R_CRYPTO_DIR_ENCRYPT) {
sk[i] = k[i + 4];
} else {
sk[31 - i] = k[i + 4];
}
}
return true;
}