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pqcrypto/crypto_kem/ledakemlt12/clean/gf2x_arith.h

64 lines
2.0 KiB
C

#ifndef GF2X_ARITH_H
#define GF2X_ARITH_H
#include <inttypes.h>
#include <stddef.h>
/*
* Elements of GF(2)[x] are stored in compact dense binary form.
*
* Each bit in a byte is assumed to be the coefficient of a binary
* polynomial f(x), in Big-Endian format (i.e., reading everything from
* left to right, the most significant element is met first):
*
* byte:(0000 0000) == 0x00 ... f(x) == 0
* byte:(0000 0001) == 0x01 ... f(x) == 1
* byte:(0000 0010) == 0x02 ... f(x) == x
* byte:(0000 0011) == 0x03 ... f(x) == x+1
* ... ... ...
* byte:(0000 1111) == 0x0F ... f(x) == x^{3}+x^{2}+x+1
* ... ... ...
* byte:(1111 1111) == 0xFF ... f(x) == x^{7}+x^{6}+x^{5}+x^{4}+x^{3}+x^{2}+x+1
*
*
* A "machine word" (A_i) is considered as a DIGIT.
* Bytes in a DIGIT are assumed in Big-Endian format:
* E.g., if sizeof(DIGIT) == 4:
* A_i: A_{i,3} A_{i,2} A_{i,1} A_{i,0}.
* A_{i,3} denotes the most significant byte, A_{i,0} the least significant one.
* f(x) == x^{31} + ... + x^{24} +
* + x^{23} + ... + x^{16} +
* + x^{15} + ... + x^{8} +
* + x^{7} + ... + x^{0}
*
*
* Multi-precision elements (i.e., with multiple DIGITs) are stored in
* Big-endian format:
* A = A_{n-1} A_{n-2} ... A_1 A_0
*
* position[A_{n-1}] == 0
* position[A_{n-2}] == 1
* ...
* position[A_{1}] == n-2
* position[A_{0}] == n-1
*/
typedef uint64_t DIGIT;
#define DIGIT_SIZE_B (8)
#define DIGIT_SIZE_b (DIGIT_SIZE_B << 3)
#define POSITION_T uint32_t
#define GF2X_MUL PQCLEAN_LEDAKEMLT12_CLEAN_gf2x_mul_comb
static inline void gf2x_add(DIGIT Res[], const DIGIT A[], const DIGIT B[], int nr) {
for (int i = 0; i < nr; i++) {
Res[i] = A[i] ^ B[i];
}
}
void PQCLEAN_LEDAKEMLT12_CLEAN_right_bit_shift_n(int length, DIGIT in[], unsigned int amount);
void PQCLEAN_LEDAKEMLT12_CLEAN_left_bit_shift_n(int length, DIGIT in[], unsigned int amount);
void GF2X_MUL(int nr, DIGIT Res[], int na, const DIGIT A[], int nb, const DIGIT B[]);
#endif