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libsec: remove affine coordinate point operations from ecc

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we now just do point addtion in jacobian coordinate system, and
convert the result to affine when s->z == nil.
This commit is contained in:
cinap_lenrek 2016-04-21 20:41:19 +02:00
parent 2fa4c8ef66
commit 42c4cc75a6
1 changed files with 18 additions and 75 deletions
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79
sys/src/libsec/port/ecc.c
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@ -35,8 +35,6 @@ ecassign(ECdomain *dom, ECpoint *a, ECpoint *b)
void void
ecadd(ECdomain *dom, ECpoint *a, ECpoint *b, ECpoint *s) ecadd(ECdomain *dom, ECpoint *a, ECpoint *b, ECpoint *s)
{ {
mpint *l, *k, *sx, *sy;
if(a->inf && b->inf){ if(a->inf && b->inf){
s->inf = 1; s->inf = 1;
return; return;
@ -50,7 +48,16 @@ ecadd(ECdomain *dom, ECpoint *a, ECpoint *b, ECpoint *s)
return; return;
} }
if(s->z != nil){ if(s->z == nil){
s->z = mpcopy(mpone);
ecadd(dom, a, b, s);
if(!s->inf)
jacobian_affine(dom->p, s->x, s->y, s->z);
mpfree(s->z);
s->z = nil;
return;
}
if(a == b) if(a == b)
jacobian_dbl(dom->p, dom->a, jacobian_dbl(dom->p, dom->a,
a->x, a->y, a->z != nil ? a->z : mpone, a->x, a->y, a->z != nil ? a->z : mpone,
@ -61,70 +68,6 @@ ecadd(ECdomain *dom, ECpoint *a, ECpoint *b, ECpoint *s)
b->x, b->y, b->z != nil ? b->z : mpone, b->x, b->y, b->z != nil ? b->z : mpone,
s->x, s->y, s->z); s->x, s->y, s->z);
s->inf = mpcmp(s->z, mpzero) == 0; s->inf = mpcmp(s->z, mpzero) == 0;
return;
}
if(mpcmp(a->x, b->x) == 0 && (mpcmp(a->y, mpzero) == 0 || mpcmp(a->y, b->y) != 0)){
s->inf = 1;
return;
}
s->inf = 0;
l = mpnew(0);
k = mpnew(0);
sx = mpnew(0);
sy = mpnew(0);
if(mpcmp(a->x, b->x) == 0 && mpcmp(a->y, b->y) == 0){
mpadd(mpone, mptwo, k);
mpmul(a->x, a->x, l);
mpmul(l, k, l);
mpadd(l, dom->a, l);
mpleft(a->y, 1, k);
mpmod(k, dom->p, k);
mpinvert(k, dom->p, k);
mpmul(k, l, l);
mpmod(l, dom->p, l);
mpleft(a->x, 1, k);
mpmul(l, l, sx);
mpsub(sx, k, sx);
mpmod(sx, dom->p, sx);
mpsub(a->x, sx, sy);
mpmul(l, sy, sy);
mpsub(sy, a->y, sy);
mpmod(sy, dom->p, sy);
mpassign(sx, s->x);
mpassign(sy, s->y);
mpfree(sx);
mpfree(sy);
mpfree(l);
mpfree(k);
return;
}
mpsub(b->y, a->y, l);
mpmod(l, dom->p, l);
mpsub(b->x, a->x, k);
mpmod(k, dom->p, k);
mpinvert(k, dom->p, k);
mpmul(k, l, l);
mpmod(l, dom->p, l);
mpmul(l, l, sx);
mpsub(sx, a->x, sx);
mpsub(sx, b->x, sx);
mpmod(sx, dom->p, sx);
mpsub(a->x, sx, sy);
mpmul(sy, l, sy);
mpsub(sy, a->y, sy);
mpmod(sy, dom->p, sy);
mpassign(sx, s->x);
mpassign(sy, s->y);
mpfree(sx);
mpfree(sy);
mpfree(l);
mpfree(k);
} }
void void
@ -173,10 +116,10 @@ ecverify(ECdomain *dom, ECpoint *a)
mpint *p, *q; mpint *p, *q;
int r; int r;
assert(a->z == nil); /* need affine coordinates */
if(a->inf) if(a->inf)
return 1; return 1;
assert(a->z == nil); /* need affine coordinates */
p = mpnew(0); p = mpnew(0);
q = mpnew(0); q = mpnew(0);
mpmodmul(a->y, a->y, dom->p, p); mpmodmul(a->y, a->y, dom->p, p);