diff options
Diffstat (limited to 'lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/ntt.c')
| -rw-r--r-- | lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/ntt.c | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/ntt.c b/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/ntt.c new file mode 100644 index 000000000..2f2eb10b2 --- /dev/null +++ b/lib/liboqs/src/kem/kyber/pqcrystals-kyber_kyber1024_ref/ntt.c @@ -0,0 +1,146 @@ +#include <stdint.h> +#include "params.h" +#include "ntt.h" +#include "reduce.h" + +/* Code to generate zetas and zetas_inv used in the number-theoretic transform: + +#define KYBER_ROOT_OF_UNITY 17 + +static const uint8_t tree[128] = { + 0, 64, 32, 96, 16, 80, 48, 112, 8, 72, 40, 104, 24, 88, 56, 120, + 4, 68, 36, 100, 20, 84, 52, 116, 12, 76, 44, 108, 28, 92, 60, 124, + 2, 66, 34, 98, 18, 82, 50, 114, 10, 74, 42, 106, 26, 90, 58, 122, + 6, 70, 38, 102, 22, 86, 54, 118, 14, 78, 46, 110, 30, 94, 62, 126, + 1, 65, 33, 97, 17, 81, 49, 113, 9, 73, 41, 105, 25, 89, 57, 121, + 5, 69, 37, 101, 21, 85, 53, 117, 13, 77, 45, 109, 29, 93, 61, 125, + 3, 67, 35, 99, 19, 83, 51, 115, 11, 75, 43, 107, 27, 91, 59, 123, + 7, 71, 39, 103, 23, 87, 55, 119, 15, 79, 47, 111, 31, 95, 63, 127 +}; + +void init_ntt() { + unsigned int i; + int16_t tmp[128]; + + tmp[0] = MONT; + for(i=1;i<128;i++) + tmp[i] = fqmul(tmp[i-1],MONT*KYBER_ROOT_OF_UNITY % KYBER_Q); + + for(i=0;i<128;i++) { + zetas[i] = tmp[tree[i]]; + if(zetas[i] > KYBER_Q/2) + zetas[i] -= KYBER_Q; + if(zetas[i] < -KYBER_Q/2) + zetas[i] += KYBER_Q; + } +} +*/ + +const int16_t zetas[128] = { + -1044, -758, -359, -1517, 1493, 1422, 287, 202, + -171, 622, 1577, 182, 962, -1202, -1474, 1468, + 573, -1325, 264, 383, -829, 1458, -1602, -130, + -681, 1017, 732, 608, -1542, 411, -205, -1571, + 1223, 652, -552, 1015, -1293, 1491, -282, -1544, + 516, -8, -320, -666, -1618, -1162, 126, 1469, + -853, -90, -271, 830, 107, -1421, -247, -951, + -398, 961, -1508, -725, 448, -1065, 677, -1275, + -1103, 430, 555, 843, -1251, 871, 1550, 105, + 422, 587, 177, -235, -291, -460, 1574, 1653, + -246, 778, 1159, -147, -777, 1483, -602, 1119, + -1590, 644, -872, 349, 418, 329, -156, -75, + 817, 1097, 603, 610, 1322, -1285, -1465, 384, + -1215, -136, 1218, -1335, -874, 220, -1187, -1659, + -1185, -1530, -1278, 794, -1510, -854, -870, 478, + -108, -308, 996, 991, 958, -1460, 1522, 1628 +}; + +/************************************************* +* Name: fqmul +* +* Description: Multiplication followed by Montgomery reduction +* +* Arguments: - int16_t a: first factor +* - int16_t b: second factor +* +* Returns 16-bit integer congruent to a*b*R^{-1} mod q +**************************************************/ +static int16_t fqmul(int16_t a, int16_t b) { + return montgomery_reduce((int32_t)a*b); +} + +/************************************************* +* Name: ntt +* +* Description: Inplace number-theoretic transform (NTT) in Rq. +* input is in standard order, output is in bitreversed order +* +* Arguments: - int16_t r[256]: pointer to input/output vector of elements of Zq +**************************************************/ +void ntt(int16_t r[256]) { + unsigned int len, start, j, k; + int16_t t, zeta; + + k = 1; + for(len = 128; len >= 2; len >>= 1) { + for(start = 0; start < 256; start = j + len) { + zeta = zetas[k++]; + for(j = start; j < start + len; j++) { + t = fqmul(zeta, r[j + len]); + r[j + len] = r[j] - t; + r[j] = r[j] + t; + } + } + } +} + +/************************************************* +* Name: invntt_tomont +* +* Description: Inplace inverse number-theoretic transform in Rq and +* multiplication by Montgomery factor 2^16. +* Input is in bitreversed order, output is in standard order +* +* Arguments: - int16_t r[256]: pointer to input/output vector of elements of Zq +**************************************************/ +void invntt(int16_t r[256]) { + unsigned int start, len, j, k; + int16_t t, zeta; + const int16_t f = 1441; // mont^2/128 + + k = 127; + for(len = 2; len <= 128; len <<= 1) { + for(start = 0; start < 256; start = j + len) { + zeta = zetas[k--]; + for(j = start; j < start + len; j++) { + t = r[j]; + r[j] = barrett_reduce(t + r[j + len]); + r[j + len] = r[j + len] - t; + r[j + len] = fqmul(zeta, r[j + len]); + } + } + } + + for(j = 0; j < 256; j++) + r[j] = fqmul(r[j], f); +} + +/************************************************* +* Name: basemul +* +* Description: Multiplication of polynomials in Zq[X]/(X^2-zeta) +* used for multiplication of elements in Rq in NTT domain +* +* Arguments: - int16_t r[2]: pointer to the output polynomial +* - const int16_t a[2]: pointer to the first factor +* - const int16_t b[2]: pointer to the second factor +* - int16_t zeta: integer defining the reduction polynomial +**************************************************/ +void basemul(int16_t r[2], const int16_t a[2], const int16_t b[2], int16_t zeta) +{ + r[0] = fqmul(a[1], b[1]); + r[0] = fqmul(r[0], zeta); + r[0] += fqmul(a[0], b[0]); + r[1] = fqmul(a[0], b[1]); + r[1] += fqmul(a[1], b[0]); +} |