-/**
- * @file p448/f_generic.c
- * @author Mike Hamburg
+/*
+ * Copyright 2017-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 2015-2016 Cryptography Research, Inc.
*
- * @copyright
- * Copyright (c) 2015-2016 Cryptography Research, Inc. \n
- * Released under the MIT License. See LICENSE.txt for license information.
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
*
- * @brief Generic arithmetic which has to be compiled per field.
- *
- * @warning This file was automatically generated in Python.
- * Please do not edit it.
+ * Originally written by Mike Hamburg
*/
#include "field.h"
-static const gf MODULUS = {FIELD_LITERAL(
- 0xffffffffffffff, 0xffffffffffffff, 0xffffffffffffff, 0xffffffffffffff, 0xfffffffffffffe, 0xffffffffffffff, 0xffffffffffffff, 0xffffffffffffff
-)};
+static const gf MODULUS = {
+ FIELD_LITERAL(0xffffffffffffff, 0xffffffffffffff, 0xffffffffffffff,
+ 0xffffffffffffff, 0xfffffffffffffe, 0xffffffffffffff,
+ 0xffffffffffffff, 0xffffffffffffff)
+};
-/** Serialize to wire format. */
-void gf_serialize (uint8_t serial[SER_BYTES], const gf x, int with_hibit) {
+/* Serialize to wire format. */
+void gf_serialize(uint8_t serial[SER_BYTES], const gf x, int with_hibit)
+{
+ unsigned int j = 0, fill = 0;
+ dword_t buffer = 0;
+ int i;
gf red;
+
gf_copy(red, x);
gf_strong_reduce(red);
- if (!with_hibit) { assert(gf_hibit(red) == 0); }
-
- unsigned int j=0, fill=0;
- dword_t buffer = 0;
- UNROLL for (unsigned int i=0; i<(with_hibit ? X_SER_BYTES : SER_BYTES); i++) {
+ if (!with_hibit)
+ assert(gf_hibit(red) == 0);
+
+ UNROLL for (i = 0; i < (with_hibit ? X_SER_BYTES : SER_BYTES); i++) {
if (fill < 8 && j < NLIMBS) {
- buffer |= ((dword_t)red->limb[LIMBPERM(j)]) << fill;
+ buffer |= ((dword_t) red->limb[LIMBPERM(j)]) << fill;
fill += LIMB_PLACE_VALUE(LIMBPERM(j));
j++;
}
- serial[i] = buffer;
+ serial[i] = (uint8_t)buffer;
fill -= 8;
buffer >>= 8;
}
}
-/** Return high bit of x = low bit of 2x mod p */
-mask_t gf_hibit(const gf x) {
+/* Return high bit of x = low bit of 2x mod p */
+mask_t gf_hibit(const gf x)
+{
gf y;
- gf_add(y,x,x);
+ gf_add(y, x, x);
gf_strong_reduce(y);
- return -(y->limb[0]&1);
+ return 0 - (y->limb[0] & 1);
}
-/** Return high bit of x = low bit of 2x mod p */
-mask_t gf_lobit(const gf x) {
+/* Return high bit of x = low bit of 2x mod p */
+mask_t gf_lobit(const gf x)
+{
gf y;
- gf_copy(y,x);
+ gf_copy(y, x);
gf_strong_reduce(y);
- return -(y->limb[0]&1);
+ return 0 - (y->limb[0] & 1);
}
-/** Deserialize from wire format; return -1 on success and 0 on failure. */
-mask_t gf_deserialize (gf x, const uint8_t serial[SER_BYTES], int with_hibit, uint8_t hi_nmask) {
- unsigned int j=0, fill=0;
+/* Deserialize from wire format; return -1 on success and 0 on failure. */
+mask_t gf_deserialize(gf x, const uint8_t serial[SER_BYTES], int with_hibit,
+ uint8_t hi_nmask)
+{
+ unsigned int j = 0, fill = 0;
dword_t buffer = 0;
dsword_t scarry = 0;
const unsigned nbytes = with_hibit ? X_SER_BYTES : SER_BYTES;
- UNROLL for (unsigned int i=0; i<NLIMBS; i++) {
+ unsigned int i;
+ mask_t succ;
+
+ UNROLL for (i = 0; i < NLIMBS; i++) {
UNROLL while (fill < LIMB_PLACE_VALUE(LIMBPERM(i)) && j < nbytes) {
uint8_t sj = serial[j];
- if (j==nbytes-1) sj &= ~hi_nmask;
- buffer |= ((dword_t)sj) << fill;
+ if (j == nbytes - 1)
+ sj &= ~hi_nmask;
+ buffer |= ((dword_t) sj) << fill;
fill += 8;
j++;
}
- x->limb[LIMBPERM(i)] = (i<NLIMBS-1) ? buffer & LIMB_MASK(LIMBPERM(i)) : buffer;
+ x->limb[LIMBPERM(i)] = (word_t)
+ ((i < NLIMBS - 1) ? buffer & LIMB_MASK(LIMBPERM(i)) : buffer);
fill -= LIMB_PLACE_VALUE(LIMBPERM(i));
buffer >>= LIMB_PLACE_VALUE(LIMBPERM(i));
- scarry = (scarry + x->limb[LIMBPERM(i)] - MODULUS->limb[LIMBPERM(i)]) >> (8*sizeof(word_t));
+ scarry =
+ (scarry + x->limb[LIMBPERM(i)] -
+ MODULUS->limb[LIMBPERM(i)]) >> (8 * sizeof(word_t));
}
- mask_t succ = with_hibit ? -(mask_t)1 : ~gf_hibit(x);
- return succ & word_is_zero(buffer) & ~word_is_zero(scarry);
+ succ = with_hibit ? 0 - (mask_t) 1 : ~gf_hibit(x);
+ return succ & word_is_zero((word_t)buffer) & ~word_is_zero((word_t)scarry);
}
-/** Reduce to canonical form. */
-void gf_strong_reduce (gf a) {
+/* Reduce to canonical form. */
+void gf_strong_reduce(gf a)
+{
+ dsword_t scarry;
+ word_t scarry_0;
+ dword_t carry = 0;
+ unsigned int i;
+
/* first, clear high */
- gf_weak_reduce(a); /* Determined to have negligible perf impact. */
+ gf_weak_reduce(a); /* Determined to have negligible perf impact. */
/* now the total is less than 2p */
/* compute total_value - p. No need to reduce mod p. */
- dsword_t scarry = 0;
- for (unsigned int i=0; i<NLIMBS; i++) {
+ scarry = 0;
+ for (i = 0; i < NLIMBS; i++) {
scarry = scarry + a->limb[LIMBPERM(i)] - MODULUS->limb[LIMBPERM(i)];
a->limb[LIMBPERM(i)] = scarry & LIMB_MASK(LIMBPERM(i));
scarry >>= LIMB_PLACE_VALUE(LIMBPERM(i));
}
- /* uncommon case: it was >= p, so now scarry = 0 and this = x
- * common case: it was < p, so now scarry = -1 and this = x - p + 2^255
- * so let's add back in p. will carry back off the top for 2^255.
+ /*
+ * uncommon case: it was >= p, so now scarry = 0 and this = x common case:
+ * it was < p, so now scarry = -1 and this = x - p + 2^255 so let's add
+ * back in p. will carry back off the top for 2^255.
*/
- assert(word_is_zero(scarry) | word_is_zero(scarry+1));
+ assert(word_is_zero(scarry) | word_is_zero(scarry + 1));
- word_t scarry_0 = scarry;
- dword_t carry = 0;
+ scarry_0 = (word_t)scarry;
/* add it back */
- for (unsigned int i=0; i<NLIMBS; i++) {
- carry = carry + a->limb[LIMBPERM(i)] + (scarry_0 & MODULUS->limb[LIMBPERM(i)]);
+ for (i = 0; i < NLIMBS; i++) {
+ carry =
+ carry + a->limb[LIMBPERM(i)] +
+ (scarry_0 & MODULUS->limb[LIMBPERM(i)]);
a->limb[LIMBPERM(i)] = carry & LIMB_MASK(LIMBPERM(i));
carry >>= LIMB_PLACE_VALUE(LIMBPERM(i));
}
assert(word_is_zero(carry + scarry_0));
}
-/** Subtract two gf elements d=a-b */
-void gf_sub (gf d, const gf a, const gf b) {
- gf_sub_RAW ( d, a, b );
- gf_bias( d, 2 );
- gf_weak_reduce ( d );
+/* Subtract two gf elements d=a-b */
+void gf_sub(gf d, const gf a, const gf b)
+{
+ gf_sub_RAW(d, a, b);
+ gf_bias(d, 2);
+ gf_weak_reduce(d);
}
-/** Add two field elements d = a+b */
-void gf_add (gf d, const gf a, const gf b) {
- gf_add_RAW ( d, a, b );
- gf_weak_reduce ( d );
+/* Add two field elements d = a+b */
+void gf_add(gf d, const gf a, const gf b)
+{
+ gf_add_RAW(d, a, b);
+ gf_weak_reduce(d);
}
-/** Compare a==b */
-mask_t gf_eq(const gf a, const gf b) {
+/* Compare a==b */
+mask_t gf_eq(const gf a, const gf b)
+{
gf c;
- gf_sub(c,a,b);
+ mask_t ret = 0;
+ unsigned int i;
+
+ gf_sub(c, a, b);
gf_strong_reduce(c);
- mask_t ret=0;
- for (unsigned int i=0; i<NLIMBS; i++) {
+
+ for (i = 0; i < NLIMBS; i++) {
ret |= c->limb[LIMBPERM(i)];
}
return word_is_zero(ret);
}
+
+mask_t gf_isr(gf a, const gf x)
+{
+ gf L0, L1, L2;
+ gf_sqr(L1, x);
+ gf_mul(L2, x, L1);
+ gf_sqr(L1, L2);
+ gf_mul(L2, x, L1);
+ gf_sqrn(L1, L2, 3);
+ gf_mul(L0, L2, L1);
+ gf_sqrn(L1, L0, 3);
+ gf_mul(L0, L2, L1);
+ gf_sqrn(L2, L0, 9);
+ gf_mul(L1, L0, L2);
+ gf_sqr(L0, L1);
+ gf_mul(L2, x, L0);
+ gf_sqrn(L0, L2, 18);
+ gf_mul(L2, L1, L0);
+ gf_sqrn(L0, L2, 37);
+ gf_mul(L1, L2, L0);
+ gf_sqrn(L0, L1, 37);
+ gf_mul(L1, L2, L0);
+ gf_sqrn(L0, L1, 111);
+ gf_mul(L2, L1, L0);
+ gf_sqr(L0, L2);
+ gf_mul(L1, x, L0);
+ gf_sqrn(L0, L1, 223);
+ gf_mul(L1, L2, L0);
+ gf_sqr(L2, L1);
+ gf_mul(L0, L2, x);
+ gf_copy(a, L1);
+ return gf_eq(L0, ONE);
+}