#define EDDSA_USE_SIGMA_ISOGENY 0
static const int EDWARDS_D = -39081;
-static const scalar_t point_scalarmul_adjustment = {{{
- SC_LIMB(0xc873d6d54a7bb0cf), SC_LIMB(0xe933d8d723a70aad), SC_LIMB(0xbb124b65129c96fd), SC_LIMB(0x00000008335dc163)
-}}}, precomputed_scalarmul_adjustment = {{{
+static const scalar_t precomputed_scalarmul_adjustment = {{{
SC_LIMB(0xc873d6d54a7bb0cf), SC_LIMB(0xe933d8d723a70aad), SC_LIMB(0xbb124b65129c96fd), SC_LIMB(0x00000008335dc163)
}}};
#define WBITS DECAF_WORD_BITS /* NB this may be different from ARCH_WORD_BITS */
-extern const point_t API_NS(point_base);
-
/* Projective Niels coordinates */
typedef struct { gf a, b, c; } niels_s, niels_t[1];
typedef struct { niels_t n; gf z; } VECTOR_ALIGNED pniels_s, pniels_t[1];
const precomputed_s *API_NS(precomputed_base) =
(const precomputed_s *) &API_NS(precomputed_base_as_fe);
-const size_t API_NS(sizeof_precomputed_s) = sizeof(precomputed_s);
-const size_t API_NS(alignof_precomputed_s) = sizeof(big_register_t);
-
/** Inverse. */
static void
gf_invert(gf y, const gf x, int assert_nonzero) {
/** identity = (0,1) */
const point_t API_NS(point_identity) = {{{{{0}}},{{{1}}},{{{1}}},{{{0}}}}};
-/* Predeclare because not static: called by elligator */
-void API_NS(deisogenize) (
- gf_s *__restrict__ s,
- gf_s *__restrict__ inv_el_sum,
- gf_s *__restrict__ inv_el_m1,
- const point_t p,
- mask_t toggle_s,
- mask_t toggle_altx,
- mask_t toggle_rotation
-);
-
-void API_NS(deisogenize) (
- gf_s *__restrict__ s,
- gf_s *__restrict__ inv_el_sum,
- gf_s *__restrict__ inv_el_m1,
- const point_t p,
- mask_t toggle_s,
- mask_t toggle_altx,
- mask_t toggle_rotation
-) {
-#if COFACTOR == 4 && !IMAGINE_TWIST
- (void)toggle_rotation; /* Only applies to cofactor 8 */
- gf t1;
- gf_s *t2 = s, *t3=inv_el_sum, *t4=inv_el_m1;
-
- gf_add(t1,p->x,p->t);
- gf_sub(t2,p->x,p->t);
- gf_mul(t3,t1,t2); /* t3 = num */
- gf_sqr(t2,p->x);
- gf_mul(t1,t2,t3);
- gf_mulw(t2,t1,-1-TWISTED_D); /* -x^2 * (a-d) * num */
- gf_isr(t1,t2); /* t1 = isr */
- gf_mul(t2,t1,t3); /* t2 = ratio */
- gf_mul(t4,t2,RISTRETTO_FACTOR);
- mask_t negx = gf_lobit(t4) ^ toggle_altx;
- gf_cond_neg(t2, negx);
- gf_mul(t3,t2,p->z);
- gf_sub(t3,t3,p->t);
- gf_mul(t2,t3,p->x);
- gf_mulw(t4,t2,-1-TWISTED_D);
- gf_mul(s,t4,t1);
- mask_t lobs = gf_lobit(s);
- gf_cond_neg(s,lobs);
- gf_copy(inv_el_m1,p->x);
- gf_cond_neg(inv_el_m1,~lobs^negx^toggle_s);
- gf_add(inv_el_m1,inv_el_m1,p->t);
-
-#elif COFACTOR == 8 && IMAGINE_TWIST
- /* More complicated because of rotation */
- gf t1,t2,t3,t4,t5;
- gf_add(t1,p->z,p->y);
- gf_sub(t2,p->z,p->y);
- gf_mul(t3,t1,t2); /* t3 = num */
- gf_mul(t2,p->x,p->y); /* t2 = den */
- gf_sqr(t1,t2);
- gf_mul(t4,t1,t3);
- gf_mulw(t1,t4,-1-TWISTED_D);
- gf_isr(t4,t1); /* isqrt(num*(a-d)*den^2) */
- gf_mul(t1,t2,t4);
- gf_mul(t2,t1,RISTRETTO_FACTOR); /* t2 = "iden" in ristretto.sage */
- gf_mul(t1,t3,t4); /* t1 = "inum" in ristretto.sage */
-
- /* Calculate altxy = iden*inum*i*t^2*(d-a) */
- gf_mul(t3,t1,t2);
- gf_mul_i(t4,t3);
- gf_mul(t3,t4,p->t);
- gf_mul(t4,t3,p->t);
- gf_mulw(t3,t4,TWISTED_D+1); /* iden*inum*i*t^2*(d-1) */
- mask_t rotate = toggle_rotation ^ gf_lobit(t3);
-
- /* Rotate if altxy is negative */
- gf_cond_swap(t1,t2,rotate);
- gf_mul_i(t4,p->x);
- gf_cond_sel(t4,p->y,t4,rotate); /* t4 = "fac" = ix if rotate, else y */
-
- gf_mul_i(t5,RISTRETTO_FACTOR); /* t5 = imi */
- gf_mul(t3,t5,t2); /* iden * imi */
- gf_mul(t2,t5,t1);
- gf_mul(t5,t2,p->t); /* "altx" = iden*imi*t */
- mask_t negx = gf_lobit(t5) ^ toggle_altx;
-
- gf_cond_neg(t1,negx^rotate);
- gf_mul(t2,t1,p->z);
- gf_add(t2,t2,ONE);
- gf_mul(inv_el_sum,t2,t4);
- gf_mul(s,inv_el_sum,t3);
-
- mask_t negs = gf_lobit(s);
- gf_cond_neg(s,negs);
-
- mask_t negz = ~negs ^ toggle_s ^ negx;
- gf_copy(inv_el_m1,p->z);
- gf_cond_neg(inv_el_m1,negz);
- gf_sub(inv_el_m1,inv_el_m1,t4);
-#else
-#error "Cofactor must be 4 (with no IMAGINE_TWIST) or 8 (with IMAGINE_TWIST)"
-#endif
-}
-
-void API_NS(point_encode)( unsigned char ser[SER_BYTES], const point_t p ) {
- gf s,ie1,ie2;
- API_NS(deisogenize)(s,ie1,ie2,p,0,0,0);
- gf_serialize(ser,s,1);
-}
-
-decaf_error_t API_NS(point_decode) (
- point_t p,
- const unsigned char ser[SER_BYTES],
- decaf_bool_t allow_identity
-) {
- gf s, s2, num, tmp;
- gf_s *tmp2=s2, *ynum=p->z, *isr=p->x, *den=p->t;
-
- mask_t succ = gf_deserialize(s, ser, 1, 0);
- succ &= bool_to_mask(allow_identity) | ~gf_eq(s, ZERO);
- succ &= ~gf_lobit(s);
-
- gf_sqr(s2,s); /* s^2 = -as^2 */
-#if IMAGINE_TWIST
- gf_sub(s2,ZERO,s2); /* -as^2 */
-#endif
- gf_sub(den,ONE,s2); /* 1+as^2 */
- gf_add(ynum,ONE,s2); /* 1-as^2 */
- gf_mulw(num,s2,-4*TWISTED_D);
- gf_sqr(tmp,den); /* tmp = den^2 */
- gf_add(num,tmp,num); /* num = den^2 - 4*d*s^2 */
- gf_mul(tmp2,num,tmp); /* tmp2 = num*den^2 */
- succ &= gf_isr(isr,tmp2); /* isr = 1/sqrt(num*den^2) */
- gf_mul(tmp,isr,den); /* isr*den */
- gf_mul(p->y,tmp,ynum); /* isr*den*(1-as^2) */
- gf_mul(tmp2,tmp,s); /* s*isr*den */
- gf_add(tmp2,tmp2,tmp2); /* 2*s*isr*den */
- gf_mul(tmp,tmp2,isr); /* 2*s*isr^2*den */
- gf_mul(p->x,tmp,num); /* 2*s*isr^2*den*num */
- gf_mul(tmp,tmp2,RISTRETTO_FACTOR); /* 2*s*isr*den*magic */
- gf_cond_neg(p->x,gf_lobit(tmp)); /* flip x */
-
-#if COFACTOR==8
- /* Additionally check y != 0 and x*y*isomagic nonegative */
- succ &= ~gf_eq(p->y,ZERO);
- gf_mul(tmp,p->x,p->y);
- gf_mul(tmp2,tmp,RISTRETTO_FACTOR);
- succ &= ~gf_lobit(tmp2);
-#endif
-
-#if IMAGINE_TWIST
- gf_copy(tmp,p->x);
- gf_mul_i(p->x,tmp);
-#endif
-
- /* Fill in z and t */
- gf_copy(p->z,ONE);
- gf_mul(p->t,p->x,p->y);
-
- assert(API_NS(point_valid)(p) | ~succ);
- return decaf_succeed_if(mask_to_bool(succ));
-}
-
-void API_NS(point_sub) (
- point_t p,
- const point_t q,
- const point_t r
-) {
- gf a, b, c, d;
- gf_sub_nr ( b, q->y, q->x ); /* 3+e */
- gf_sub_nr ( d, r->y, r->x ); /* 3+e */
- gf_add_nr ( c, r->y, r->x ); /* 2+e */
- gf_mul ( a, c, b );
- gf_add_nr ( b, q->y, q->x ); /* 2+e */
- gf_mul ( p->y, d, b );
- gf_mul ( b, r->t, q->t );
- gf_mulw ( p->x, b, 2*EFF_D );
- gf_add_nr ( b, a, p->y ); /* 2+e */
- gf_sub_nr ( c, p->y, a ); /* 3+e */
- gf_mul ( a, q->z, r->z );
- gf_add_nr ( a, a, a ); /* 2+e */
- if (GF_HEADROOM <= 3) gf_weak_reduce(a); /* or 1+e */
-#if NEG_D
- gf_sub_nr ( p->y, a, p->x ); /* 4+e or 3+e */
- gf_add_nr ( a, a, p->x ); /* 3+e or 2+e */
-#else
- gf_add_nr ( p->y, a, p->x ); /* 3+e or 2+e */
- gf_sub_nr ( a, a, p->x ); /* 4+e or 3+e */
-#endif
- gf_mul ( p->z, a, p->y );
- gf_mul ( p->x, p->y, c );
- gf_mul ( p->y, a, b );
- gf_mul ( p->t, b, c );
-}
-
-void API_NS(point_add) (
- point_t p,
- const point_t q,
- const point_t r
-) {
- gf a, b, c, d;
- gf_sub_nr ( b, q->y, q->x ); /* 3+e */
- gf_sub_nr ( c, r->y, r->x ); /* 3+e */
- gf_add_nr ( d, r->y, r->x ); /* 2+e */
- gf_mul ( a, c, b );
- gf_add_nr ( b, q->y, q->x ); /* 2+e */
- gf_mul ( p->y, d, b );
- gf_mul ( b, r->t, q->t );
- gf_mulw ( p->x, b, 2*EFF_D );
- gf_add_nr ( b, a, p->y ); /* 2+e */
- gf_sub_nr ( c, p->y, a ); /* 3+e */
- gf_mul ( a, q->z, r->z );
- gf_add_nr ( a, a, a ); /* 2+e */
- if (GF_HEADROOM <= 3) gf_weak_reduce(a); /* or 1+e */
-#if NEG_D
- gf_add_nr ( p->y, a, p->x ); /* 3+e or 2+e */
- gf_sub_nr ( a, a, p->x ); /* 4+e or 3+e */
-#else
- gf_sub_nr ( p->y, a, p->x ); /* 4+e or 3+e */
- gf_add_nr ( a, a, p->x ); /* 3+e or 2+e */
-#endif
- gf_mul ( p->z, a, p->y );
- gf_mul ( p->x, p->y, c );
- gf_mul ( p->y, a, b );
- gf_mul ( p->t, b, c );
-}
-
static DECAF_NOINLINE void
point_double_internal (
point_t p,
point_double_internal(p,q,0);
}
-void API_NS(point_negate) (
- point_t nega,
- const point_t a
-) {
- gf_sub(nega->x, ZERO, a->x);
- gf_copy(nega->y, a->y);
- gf_copy(nega->z, a->z);
- gf_sub(nega->t, ZERO, a->t);
-}
-
/* Operations on [p]niels */
static DECAF_INLINE void
cond_neg_niels (
sub_niels_from_pt( p, pn->n, before_double );
}
-static DECAF_NOINLINE void
-prepare_fixed_window(
- pniels_t *multiples,
- const point_t b,
- int ntable
-) {
- point_t tmp;
- pniels_t pn;
- int i;
-
- point_double_internal(tmp, b, 0);
- pt_to_pniels(pn, tmp);
- pt_to_pniels(multiples[0], b);
- API_NS(point_copy)(tmp, b);
- for (i=1; i<ntable; i++) {
- add_pniels_to_pt(tmp, pn, 0);
- pt_to_pniels(multiples[i], tmp);
- }
-
- OPENSSL_cleanse(pn,sizeof(pn));
- OPENSSL_cleanse(tmp,sizeof(tmp));
-}
-
-void API_NS(point_scalarmul) (
- point_t a,
- const point_t b,
- const scalar_t scalar
-) {
- const int WINDOW = DECAF_WINDOW_BITS,
- WINDOW_MASK = (1<<WINDOW)-1,
- WINDOW_T_MASK = WINDOW_MASK >> 1,
- NTABLE = 1<<(WINDOW-1);
-
- scalar_t scalar1x;
- API_NS(scalar_add)(scalar1x, scalar, point_scalarmul_adjustment);
- API_NS(scalar_halve)(scalar1x,scalar1x);
-
- /* Set up a precomputed table with odd multiples of b. */
- pniels_t pn, multiples[NTABLE];
- point_t tmp;
- prepare_fixed_window(multiples, b, NTABLE);
-
- /* Initialize. */
- int i,j,first=1;
- i = SCALAR_BITS - ((SCALAR_BITS-1) % WINDOW) - 1;
-
- for (; i>=0; i-=WINDOW) {
- /* Fetch another block of bits */
- word_t bits = scalar1x->limb[i/WBITS] >> (i%WBITS);
- if (i%WBITS >= WBITS-WINDOW && i/WBITS<SCALAR_LIMBS-1) {
- bits ^= scalar1x->limb[i/WBITS+1] << (WBITS - (i%WBITS));
- }
- bits &= WINDOW_MASK;
- mask_t inv = (bits>>(WINDOW-1))-1;
- bits ^= inv;
-
- /* Add in from table. Compute t only on last iteration. */
- constant_time_lookup(pn, multiples, sizeof(pn), NTABLE, bits & WINDOW_T_MASK);
- cond_neg_niels(pn->n, inv);
- if (first) {
- pniels_to_pt(tmp, pn);
- first = 0;
- } else {
- /* Using Hisil et al's lookahead method instead of extensible here
- * for no particular reason. Double WINDOW times, but only compute t on
- * the last one.
- */
- for (j=0; j<WINDOW-1; j++)
- point_double_internal(tmp, tmp, -1);
- point_double_internal(tmp, tmp, 0);
- add_pniels_to_pt(tmp, pn, i ? -1 : 0);
- }
- }
-
- /* Write out the answer */
- API_NS(point_copy)(a,tmp);
-
- OPENSSL_cleanse(scalar1x,sizeof(scalar1x));
- OPENSSL_cleanse(pn,sizeof(pn));
- OPENSSL_cleanse(multiples,sizeof(multiples));
- OPENSSL_cleanse(tmp,sizeof(tmp));
-}
-
-void API_NS(point_double_scalarmul) (
- point_t a,
- const point_t b,
- const scalar_t scalarb,
- const point_t c,
- const scalar_t scalarc
-) {
- const int WINDOW = DECAF_WINDOW_BITS,
- WINDOW_MASK = (1<<WINDOW)-1,
- WINDOW_T_MASK = WINDOW_MASK >> 1,
- NTABLE = 1<<(WINDOW-1);
-
- scalar_t scalar1x, scalar2x;
- API_NS(scalar_add)(scalar1x, scalarb, point_scalarmul_adjustment);
- API_NS(scalar_halve)(scalar1x,scalar1x);
- API_NS(scalar_add)(scalar2x, scalarc, point_scalarmul_adjustment);
- API_NS(scalar_halve)(scalar2x,scalar2x);
-
- /* Set up a precomputed table with odd multiples of b. */
- pniels_t pn, multiples1[NTABLE], multiples2[NTABLE];
- point_t tmp;
- prepare_fixed_window(multiples1, b, NTABLE);
- prepare_fixed_window(multiples2, c, NTABLE);
-
- /* Initialize. */
- int i,j,first=1;
- i = SCALAR_BITS - ((SCALAR_BITS-1) % WINDOW) - 1;
-
- for (; i>=0; i-=WINDOW) {
- /* Fetch another block of bits */
- word_t bits1 = scalar1x->limb[i/WBITS] >> (i%WBITS),
- bits2 = scalar2x->limb[i/WBITS] >> (i%WBITS);
- if (i%WBITS >= WBITS-WINDOW && i/WBITS<SCALAR_LIMBS-1) {
- bits1 ^= scalar1x->limb[i/WBITS+1] << (WBITS - (i%WBITS));
- bits2 ^= scalar2x->limb[i/WBITS+1] << (WBITS - (i%WBITS));
- }
- bits1 &= WINDOW_MASK;
- bits2 &= WINDOW_MASK;
- mask_t inv1 = (bits1>>(WINDOW-1))-1;
- mask_t inv2 = (bits2>>(WINDOW-1))-1;
- bits1 ^= inv1;
- bits2 ^= inv2;
-
- /* Add in from table. Compute t only on last iteration. */
- constant_time_lookup(pn, multiples1, sizeof(pn), NTABLE, bits1 & WINDOW_T_MASK);
- cond_neg_niels(pn->n, inv1);
- if (first) {
- pniels_to_pt(tmp, pn);
- first = 0;
- } else {
- /* Using Hisil et al's lookahead method instead of extensible here
- * for no particular reason. Double WINDOW times, but only compute t on
- * the last one.
- */
- for (j=0; j<WINDOW-1; j++)
- point_double_internal(tmp, tmp, -1);
- point_double_internal(tmp, tmp, 0);
- add_pniels_to_pt(tmp, pn, 0);
- }
- constant_time_lookup(pn, multiples2, sizeof(pn), NTABLE, bits2 & WINDOW_T_MASK);
- cond_neg_niels(pn->n, inv2);
- add_pniels_to_pt(tmp, pn, i?-1:0);
- }
-
- /* Write out the answer */
- API_NS(point_copy)(a,tmp);
-
-
- OPENSSL_cleanse(scalar1x,sizeof(scalar1x));
- OPENSSL_cleanse(scalar2x,sizeof(scalar2x));
- OPENSSL_cleanse(pn,sizeof(pn));
- OPENSSL_cleanse(multiples1,sizeof(multiples1));
- OPENSSL_cleanse(multiples2,sizeof(multiples2));
- OPENSSL_cleanse(tmp,sizeof(tmp));
-}
-
-void API_NS(point_dual_scalarmul) (
- point_t a1,
- point_t a2,
- const point_t b,
- const scalar_t scalar1,
- const scalar_t scalar2
-) {
- const int WINDOW = DECAF_WINDOW_BITS,
- WINDOW_MASK = (1<<WINDOW)-1,
- WINDOW_T_MASK = WINDOW_MASK >> 1,
- NTABLE = 1<<(WINDOW-1);
-
- scalar_t scalar1x, scalar2x;
- API_NS(scalar_add)(scalar1x, scalar1, point_scalarmul_adjustment);
- API_NS(scalar_halve)(scalar1x,scalar1x);
- API_NS(scalar_add)(scalar2x, scalar2, point_scalarmul_adjustment);
- API_NS(scalar_halve)(scalar2x,scalar2x);
-
- /* Set up a precomputed table with odd multiples of b. */
- point_t multiples1[NTABLE], multiples2[NTABLE], working, tmp;
- pniels_t pn;
-
- API_NS(point_copy)(working, b);
-
- /* Initialize. */
- int i,j;
-
- for (i=0; i<NTABLE; i++) {
- API_NS(point_copy)(multiples1[i], API_NS(point_identity));
- API_NS(point_copy)(multiples2[i], API_NS(point_identity));
- }
-
- for (i=0; i<SCALAR_BITS; i+=WINDOW) {
- if (i) {
- for (j=0; j<WINDOW-1; j++)
- point_double_internal(working, working, -1);
- point_double_internal(working, working, 0);
- }
-
- /* Fetch another block of bits */
- word_t bits1 = scalar1x->limb[i/WBITS] >> (i%WBITS),
- bits2 = scalar2x->limb[i/WBITS] >> (i%WBITS);
- if (i%WBITS >= WBITS-WINDOW && i/WBITS<SCALAR_LIMBS-1) {
- bits1 ^= scalar1x->limb[i/WBITS+1] << (WBITS - (i%WBITS));
- bits2 ^= scalar2x->limb[i/WBITS+1] << (WBITS - (i%WBITS));
- }
- bits1 &= WINDOW_MASK;
- bits2 &= WINDOW_MASK;
- mask_t inv1 = (bits1>>(WINDOW-1))-1;
- mask_t inv2 = (bits2>>(WINDOW-1))-1;
- bits1 ^= inv1;
- bits2 ^= inv2;
-
- pt_to_pniels(pn, working);
-
- constant_time_lookup(tmp, multiples1, sizeof(tmp), NTABLE, bits1 & WINDOW_T_MASK);
- cond_neg_niels(pn->n, inv1);
- /* add_pniels_to_pt(multiples1[bits1 & WINDOW_T_MASK], pn, 0); */
- add_pniels_to_pt(tmp, pn, 0);
- constant_time_insert(multiples1, tmp, sizeof(tmp), NTABLE, bits1 & WINDOW_T_MASK);
-
-
- constant_time_lookup(tmp, multiples2, sizeof(tmp), NTABLE, bits2 & WINDOW_T_MASK);
- cond_neg_niels(pn->n, inv1^inv2);
- /* add_pniels_to_pt(multiples2[bits2 & WINDOW_T_MASK], pn, 0); */
- add_pniels_to_pt(tmp, pn, 0);
- constant_time_insert(multiples2, tmp, sizeof(tmp), NTABLE, bits2 & WINDOW_T_MASK);
- }
-
- if (NTABLE > 1) {
- API_NS(point_copy)(working, multiples1[NTABLE-1]);
- API_NS(point_copy)(tmp , multiples2[NTABLE-1]);
-
- for (i=NTABLE-1; i>1; i--) {
- API_NS(point_add)(multiples1[i-1], multiples1[i-1], multiples1[i]);
- API_NS(point_add)(multiples2[i-1], multiples2[i-1], multiples2[i]);
- API_NS(point_add)(working, working, multiples1[i-1]);
- API_NS(point_add)(tmp, tmp, multiples2[i-1]);
- }
-
- API_NS(point_add)(multiples1[0], multiples1[0], multiples1[1]);
- API_NS(point_add)(multiples2[0], multiples2[0], multiples2[1]);
- point_double_internal(working, working, 0);
- point_double_internal(tmp, tmp, 0);
- API_NS(point_add)(a1, working, multiples1[0]);
- API_NS(point_add)(a2, tmp, multiples2[0]);
- } else {
- API_NS(point_copy)(a1, multiples1[0]);
- API_NS(point_copy)(a2, multiples2[0]);
- }
-
- OPENSSL_cleanse(scalar1x,sizeof(scalar1x));
- OPENSSL_cleanse(scalar2x,sizeof(scalar2x));
- OPENSSL_cleanse(pn,sizeof(pn));
- OPENSSL_cleanse(multiples1,sizeof(multiples1));
- OPENSSL_cleanse(multiples2,sizeof(multiples2));
- OPENSSL_cleanse(tmp,sizeof(tmp));
- OPENSSL_cleanse(working,sizeof(working));
-}
-
decaf_bool_t API_NS(point_eq) ( const point_t p, const point_t q ) {
/* equality mod 2-torsion compares x/y */
gf a, b;
return mask_to_bool(out);
}
-void API_NS(point_debugging_torque) (
- point_t q,
- const point_t p
-) {
-#if COFACTOR == 8 && IMAGINE_TWIST
- gf tmp;
- gf_mul(tmp,p->x,SQRT_MINUS_ONE);
- gf_mul(q->x,p->y,SQRT_MINUS_ONE);
- gf_copy(q->y,tmp);
- gf_copy(q->z,p->z);
- gf_sub(q->t,ZERO,p->t);
-#else
- gf_sub(q->x,ZERO,p->x);
- gf_sub(q->y,ZERO,p->y);
- gf_copy(q->z,p->z);
- gf_copy(q->t,p->t);
-#endif
-}
-
-void API_NS(point_debugging_pscale) (
- point_t q,
- const point_t p,
- const uint8_t factor[SER_BYTES]
-) {
- gf gfac,tmp;
- /* NB this means you'll never pscale by negative numbers for p521 */
- ignore_result(gf_deserialize(gfac,factor,0,0));
- gf_cond_sel(gfac,gfac,ONE,gf_eq(gfac,ZERO));
- gf_mul(tmp,p->x,gfac);
- gf_copy(q->x,tmp);
- gf_mul(tmp,p->y,gfac);
- gf_copy(q->y,tmp);
- gf_mul(tmp,p->z,gfac);
- gf_copy(q->z,tmp);
- gf_mul(tmp,p->t,gfac);
- gf_copy(q->t,tmp);
-}
-
-static void gf_batch_invert (
- gf *__restrict__ out,
- const gf *in,
- unsigned int n
-) {
- gf t1;
- assert(n>1);
-
- gf_copy(out[1], in[0]);
- int i;
- for (i=1; i<(int) (n-1); i++) {
- gf_mul(out[i+1], out[i], in[i]);
- }
- gf_mul(out[0], out[n-1], in[n-1]);
-
- gf_invert(out[0], out[0], 1);
-
- for (i=n-1; i>0; i--) {
- gf_mul(t1, out[i], out[0]);
- gf_copy(out[i], t1);
- gf_mul(t1, out[0], in[i]);
- gf_copy(out[0], t1);
- }
-}
-
-static void batch_normalize_niels (
- niels_t *table,
- const gf *zs,
- gf *__restrict__ zis,
- int n
-) {
- int i;
- gf product;
- gf_batch_invert(zis, zs, n);
-
- for (i=0; i<n; i++) {
- gf_mul(product, table[i]->a, zis[i]);
- gf_strong_reduce(product);
- gf_copy(table[i]->a, product);
-
- gf_mul(product, table[i]->b, zis[i]);
- gf_strong_reduce(product);
- gf_copy(table[i]->b, product);
-
- gf_mul(product, table[i]->c, zis[i]);
- gf_strong_reduce(product);
- gf_copy(table[i]->c, product);
- }
-
- OPENSSL_cleanse(product,sizeof(product));
-}
-
-void API_NS(precompute) (
- precomputed_s *table,
- const point_t base
-) {
- const unsigned int n = COMBS_N, t = COMBS_T, s = COMBS_S;
- assert(n*t*s >= SCALAR_BITS);
-
- point_t working, start, doubles[t-1];
- API_NS(point_copy)(working, base);
- pniels_t pn_tmp;
-
- gf zs[n<<(t-1)], zis[n<<(t-1)];
-
- unsigned int i,j,k;
-
- /* Compute n tables */
- for (i=0; i<n; i++) {
-
- /* Doubling phase */
- for (j=0; j<t; j++) {
- if (j) API_NS(point_add)(start, start, working);
- else API_NS(point_copy)(start, working);
-
- if (j==t-1 && i==n-1) break;
-
- point_double_internal(working, working,0);
- if (j<t-1) API_NS(point_copy)(doubles[j], working);
-
- for (k=0; k<s-1; k++)
- point_double_internal(working, working, k<s-2);
- }
-
- /* Gray-code phase */
- for (j=0;; j++) {
- int gray = j ^ (j>>1);
- int idx = (((i+1)<<(t-1))-1) ^ gray;
-
- pt_to_pniels(pn_tmp, start);
- memcpy(table->table[idx], pn_tmp->n, sizeof(pn_tmp->n));
- gf_copy(zs[idx], pn_tmp->z);
-
- if (j >= (1u<<(t-1)) - 1) break;
- int delta = (j+1) ^ ((j+1)>>1) ^ gray;
-
- for (k=0; delta>1; k++)
- delta >>=1;
-
- if (gray & (1<<k)) {
- API_NS(point_add)(start, start, doubles[k]);
- } else {
- API_NS(point_sub)(start, start, doubles[k]);
- }
- }
- }
-
- batch_normalize_niels(table->table,(const gf *)zs,zis,n<<(t-1));
-
- OPENSSL_cleanse(zs,sizeof(zs));
- OPENSSL_cleanse(zis,sizeof(zis));
- OPENSSL_cleanse(pn_tmp,sizeof(pn_tmp));
- OPENSSL_cleanse(working,sizeof(working));
- OPENSSL_cleanse(start,sizeof(start));
- OPENSSL_cleanse(doubles,sizeof(doubles));
-}
-
static DECAF_INLINE void
constant_time_lookup_niels (
niels_s *__restrict__ ni,
OPENSSL_cleanse(scalar1x,sizeof(scalar1x));
}
-void API_NS(point_cond_sel) (
- point_t out,
- const point_t a,
- const point_t b,
- decaf_bool_t pick_b
-) {
- constant_time_select(out,a,b,sizeof(point_t),bool_to_mask(pick_b),0);
-}
-
-/* FUTURE: restore Curve25519 Montgomery ladder? */
-decaf_error_t API_NS(direct_scalarmul) (
- uint8_t scaled[SER_BYTES],
- const uint8_t base[SER_BYTES],
- const scalar_t scalar,
- decaf_bool_t allow_identity,
- decaf_bool_t short_circuit
-) {
- point_t basep;
- decaf_error_t succ = API_NS(point_decode)(basep, base, allow_identity);
- if (short_circuit && succ != DECAF_SUCCESS) return succ;
- API_NS(point_cond_sel)(basep, API_NS(point_base), basep, succ);
- API_NS(point_scalarmul)(basep, basep, scalar);
- API_NS(point_encode)(scaled, basep);
- API_NS(point_destroy)(basep);
- return succ;
-}
-
void API_NS(point_mul_by_ratio_and_encode_like_eddsa) (
uint8_t enc[DECAF_EDDSA_448_PUBLIC_BYTES],
const point_t p
extern const gf API_NS(precomputed_wnaf_as_fe)[];
static const niels_t *API_NS(wnaf_base) = (const niels_t *)API_NS(precomputed_wnaf_as_fe);
-const size_t API_NS(sizeof_precomputed_wnafs) __attribute((visibility("hidden")))
- = sizeof(niels_t)<<DECAF_WNAF_FIXED_TABLE_BITS;
-
-void API_NS(precompute_wnafs) (
- niels_t out[1<<DECAF_WNAF_FIXED_TABLE_BITS],
- const point_t base
-) __attribute__ ((visibility ("hidden")));
-
-void API_NS(precompute_wnafs) (
- niels_t out[1<<DECAF_WNAF_FIXED_TABLE_BITS],
- const point_t base
-) {
- pniels_t tmp[1<<DECAF_WNAF_FIXED_TABLE_BITS];
- gf zs[1<<DECAF_WNAF_FIXED_TABLE_BITS], zis[1<<DECAF_WNAF_FIXED_TABLE_BITS];
- int i;
- prepare_wnaf_table(tmp,base,DECAF_WNAF_FIXED_TABLE_BITS);
- for (i=0; i<1<<DECAF_WNAF_FIXED_TABLE_BITS; i++) {
- memcpy(out[i], tmp[i]->n, sizeof(niels_t));
- gf_copy(zs[i], tmp[i]->z);
- }
- batch_normalize_niels(out, (const gf *)zs, zis, 1<<DECAF_WNAF_FIXED_TABLE_BITS);
-
- OPENSSL_cleanse(tmp,sizeof(tmp));
- OPENSSL_cleanse(zs,sizeof(zs));
- OPENSSL_cleanse(zis,sizeof(zis));
-}
void API_NS(base_double_scalarmul_non_secret) (
point_t combo,
OPENSSL_cleanse(point, sizeof(point_t));
}
-void API_NS(precomputed_destroy) (
- precomputed_s *pre
-) {
- OPENSSL_cleanse(pre, API_NS(sizeof_precomputed_s));
-}
-
int X448(uint8_t out_shared_key[56], const uint8_t private_key[56],
const uint8_t peer_public_value[56])
{
/** Precomputed table based on a point. Can be trivial implementation. */
typedef struct decaf_448_precomputed_s decaf_448_precomputed_s;
-/** Size and alignment of precomputed point tables. */
-extern const size_t decaf_448_sizeof_precomputed_s DECAF_API_VIS, decaf_448_alignof_precomputed_s DECAF_API_VIS;
-
/** Scalar is stored packed, because we don't need the speed. */
typedef struct decaf_448_scalar_s {
/** @cond internal */
uint64_t a
) DECAF_API_VIS DECAF_NONNULL;
-/**
- * @brief Encode a point as a sequence of bytes.
- *
- * @param [out] ser The byte representation of the point.
- * @param [in] pt The point to encode.
- */
-void decaf_448_point_encode (
- uint8_t ser[DECAF_448_SER_BYTES],
- const decaf_448_point_t pt
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Decode a point from a sequence of bytes.
- *
- * Every point has a unique encoding, so not every
- * sequence of bytes is a valid encoding. If an invalid
- * encoding is given, the output is undefined.
- *
- * @param [out] pt The decoded point.
- * @param [in] ser The serialized version of the point.
- * @param [in] allow_identity DECAF_TRUE if the identity is a legal input.
- * @retval DECAF_SUCCESS The decoding succeeded.
- * @retval DECAF_FAILURE The decoding didn't succeed, because
- * ser does not represent a point.
- */
-decaf_error_t decaf_448_point_decode (
- decaf_448_point_t pt,
- const uint8_t ser[DECAF_448_SER_BYTES],
- decaf_bool_t allow_identity
-) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-
/**
* @brief Copy a point. The input and output may alias,
* in which case this function does nothing.
const decaf_448_point_t b
) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-/**
- * @brief Add two points to produce a third point. The
- * input points and output point can be pointers to the same
- * memory.
- *
- * @param [out] sum The sum a+b.
- * @param [in] a An addend.
- * @param [in] b An addend.
- */
-void decaf_448_point_add (
- decaf_448_point_t sum,
- const decaf_448_point_t a,
- const decaf_448_point_t b
-) DECAF_API_VIS DECAF_NONNULL;
-
/**
* @brief Double a point. Equivalent to
* decaf_448_point_add(two_a,a,a), but potentially faster.
const decaf_448_point_t a
) DECAF_API_VIS DECAF_NONNULL;
-/**
- * @brief Subtract two points to produce a third point. The
- * input points and output point can be pointers to the same
- * memory.
- *
- * @param [out] diff The difference a-b.
- * @param [in] a The minuend.
- * @param [in] b The subtrahend.
- */
-void decaf_448_point_sub (
- decaf_448_point_t diff,
- const decaf_448_point_t a,
- const decaf_448_point_t b
-) DECAF_API_VIS DECAF_NONNULL;
-
-/**
- * @brief Negate a point to produce another point. The input
- * and output points can use the same memory.
- *
- * @param [out] nega The negated input point
- * @param [in] a The input point.
- */
-void decaf_448_point_negate (
- decaf_448_point_t nega,
- const decaf_448_point_t a
-) DECAF_API_VIS DECAF_NONNULL;
-
-/**
- * @brief Multiply a base point by a scalar: scaled = scalar*base.
- *
- * @param [out] scaled The scaled point base*scalar
- * @param [in] base The point to be scaled.
- * @param [in] scalar The scalar to multiply by.
- */
-void decaf_448_point_scalarmul (
- decaf_448_point_t scaled,
- const decaf_448_point_t base,
- const decaf_448_scalar_t scalar
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Multiply a base point by a scalar: scaled = scalar*base.
- * This function operates directly on serialized forms.
- *
- * @warning This function is experimental. It may not be supported
- * long-term.
- *
- * @param [out] scaled The scaled point base*scalar
- * @param [in] base The point to be scaled.
- * @param [in] scalar The scalar to multiply by.
- * @param [in] allow_identity Allow the input to be the identity.
- * @param [in] short_circuit Allow a fast return if the input is illegal.
- *
- * @retval DECAF_SUCCESS The scalarmul succeeded.
- * @retval DECAF_FAILURE The scalarmul didn't succeed, because
- * base does not represent a point.
- */
-decaf_error_t decaf_448_direct_scalarmul (
- uint8_t scaled[DECAF_448_SER_BYTES],
- const uint8_t base[DECAF_448_SER_BYTES],
- const decaf_448_scalar_t scalar,
- decaf_bool_t allow_identity,
- decaf_bool_t short_circuit
-) DECAF_API_VIS DECAF_NONNULL DECAF_WARN_UNUSED DECAF_NOINLINE;
-
/**
* @brief RFC 7748 Diffie-Hellman scalarmul. This function uses a different
* (non-Decaf) encoding.
const decaf_448_scalar_t scalar
) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-/**
- * @brief Multiply two base points by two scalars:
- * scaled = scalar1*base1 + scalar2*base2.
- *
- * Equivalent to two calls to decaf_448_point_scalarmul, but may be
- * faster.
- *
- * @param [out] combo The linear combination scalar1*base1 + scalar2*base2.
- * @param [in] base1 A first point to be scaled.
- * @param [in] scalar1 A first scalar to multiply by.
- * @param [in] base2 A second point to be scaled.
- * @param [in] scalar2 A second scalar to multiply by.
- */
-void decaf_448_point_double_scalarmul (
- decaf_448_point_t combo,
- const decaf_448_point_t base1,
- const decaf_448_scalar_t scalar1,
- const decaf_448_point_t base2,
- const decaf_448_scalar_t scalar2
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * Multiply one base point by two scalars:
- *
- * a1 = scalar1 * base
- * a2 = scalar2 * base
- *
- * Equivalent to two calls to decaf_448_point_scalarmul, but may be
- * faster.
- *
- * @param [out] a1 The first multiple. It may be the same as the input point.
- * @param [out] a2 The second multiple. It may be the same as the input point.
- * @param [in] base1 A point to be scaled.
- * @param [in] scalar1 A first scalar to multiply by.
- * @param [in] scalar2 A second scalar to multiply by.
- */
-void decaf_448_point_dual_scalarmul (
- decaf_448_point_t a1,
- decaf_448_point_t a2,
- const decaf_448_point_t base1,
- const decaf_448_scalar_t scalar1,
- const decaf_448_scalar_t scalar2
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
/**
* @brief Multiply two base points by two scalars:
const decaf_448_scalar_t scalar2
) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-/**
- * @brief Constant-time decision between two points. If pick_b
- * is zero, out = a; else out = b.
- *
- * @param [out] out The output. It may be the same as either input.
- * @param [in] a Any point.
- * @param [in] b Any point.
- * @param [in] pick_b If nonzero, choose point b.
- */
-void decaf_448_point_cond_sel (
- decaf_448_point_t out,
- const decaf_448_point_t a,
- const decaf_448_point_t b,
- decaf_word_t pick_b
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
/**
* @brief Constant-time decision between two scalars. If pick_b
* is zero, out = a; else out = b.
const decaf_448_point_t to_test
) DECAF_API_VIS DECAF_WARN_UNUSED DECAF_NONNULL DECAF_NOINLINE;
-/**
- * @brief Torque a point, for debugging purposes. The output
- * will be equal to the input.
- *
- * @param [out] q The point to torque.
- * @param [in] p The point to torque.
- */
-void decaf_448_point_debugging_torque (
- decaf_448_point_t q,
- const decaf_448_point_t p
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
-
-/**
- * @brief Projectively scale a point, for debugging purposes.
- * The output will be equal to the input, and will be valid
- * even if the factor is zero.
- *
- * @param [out] q The point to scale.
- * @param [in] p The point to scale.
- * @param [in] factor Serialized GF factor to scale.
- */
-void decaf_448_point_debugging_pscale (
- decaf_448_point_t q,
- const decaf_448_point_t p,
- const unsigned char factor[DECAF_448_SER_BYTES]
-) DECAF_API_VIS DECAF_NONNULL DECAF_NOINLINE;
/**
* @brief Almost-Elligator-like hash to curve.
decaf_448_point_t point
) DECAF_NONNULL DECAF_API_VIS;
-/**
- * @brief Overwrite precomputed table with zeros.
- */
-void decaf_448_precomputed_destroy (
- decaf_448_precomputed_s *pre
-) DECAF_NONNULL DECAF_API_VIS;
-
#ifdef __cplusplus
} /* extern "C" */
#endif
projects / openssl.git / commitdiff