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49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
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#ifndef _SECP256K1_UTIL_IMPL_H_
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#define _SECP256K1_UTIL_IMPL_H_
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#include <stdint.h>
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#include <string.h>
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#include "../util.h"
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static inline uint32_t secp256k1_rand32(void) {
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static uint32_t Rz = 11, Rw = 11;
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Rz = 36969 * (Rz & 0xFFFF) + (Rz >> 16);
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Rw = 18000 * (Rw & 0xFFFF) + (Rw >> 16);
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return (Rw << 16) + Rz;
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}
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static void secp256k1_rand256(unsigned char *b32) {
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for (int i=0; i<8; i++) {
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uint32_t r = secp256k1_rand32();
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b32[i*4 + 0] = (r >> 0) & 0xFF;
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b32[i*4 + 1] = (r >> 8) & 0xFF;
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b32[i*4 + 2] = (r >> 16) & 0xFF;
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b32[i*4 + 3] = (r >> 24) & 0xFF;
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}
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}
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static void secp256k1_rand256_test(unsigned char *b32) {
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int bits=0;
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uint32_t ent;
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int entbits = 0;
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memset(b32, 0, 32);
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while (bits < 256) {
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if (entbits < 15) {
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ent = secp256k1_rand32();
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entbits = 32;
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}
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int now = 1 + ((ent % 64)*((ent >> 6) % 32)+16)/31;
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uint32_t val = 1 & (ent >> 11);
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ent -= 12;
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entbits >>= 12;
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while (now > 0 && bits < 256) {
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b32[bits / 8] |= val << (bits % 8);
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now--;
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bits++;
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}
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}
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}
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#endif
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