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/*
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
*/
//
// pair256.swift
//
// Created by Michael Scott on 07/07/2015.
// Copyright (c) 2015 Michael Scott. All rights reserved.
//
/* AMCL BLS Curve Pairing functions */
public struct PAIR256 {
// Line function
static func linedbl(_ A: inout ECP8,_ Qx:FP,_ Qy:FP) -> FP48
{
var a:FP16
var b:FP16
var c:FP16
var XX=FP8(A.getx()) //X
var YY=FP8(A.gety()) //Y
var ZZ=FP8(A.getz()) //Z
var YZ=FP8(YY) //Y
YZ.mul(ZZ) //YZ
XX.sqr() //X^2
YY.sqr() //Y^2
ZZ.sqr() //Z^2
YZ.imul(4)
YZ.neg(); YZ.norm() //-2YZ
YZ.tmul(Qy) //-2YZ.Ys
XX.imul(6) //3X^2
XX.tmul(Qx) //3X^2.Xs
let sb=3*ROM.CURVE_B_I
ZZ.imul(sb)
if CONFIG_CURVE.SEXTIC_TWIST == CONFIG_CURVE.D_TYPE {
ZZ.div_2i();
}
if CONFIG_CURVE.SEXTIC_TWIST == CONFIG_CURVE.M_TYPE {
ZZ.times_i()
ZZ.add(ZZ)
YZ.times_i()
}
ZZ.norm() // 3b.Z^2
YY.add(YY)
ZZ.sub(YY); ZZ.norm() // 3b.Z^2-Y^2
a=FP16(YZ,ZZ) // -2YZ.Ys | 3b.Z^2-Y^2 | 3X^2.Xs
if CONFIG_CURVE.SEXTIC_TWIST == CONFIG_CURVE.D_TYPE {
b=FP16(XX) // L(0,1) | L(0,0) | L(1,0)
c=FP16(0)
} else {
b=FP16(0)
c=FP16(XX); c.times_i()
}
A.dbl()
var res=FP48(a,b,c)
res.settype(FP48.SPARSER)
return res
}
static func lineadd(_ A: inout ECP8,_ B:ECP8,_ Qx:FP,_ Qy:FP) -> FP48
{
var a:FP16
var b:FP16
var c:FP16
var X1=FP8(A.getx()) // X1
var Y1=FP8(A.gety()) // Y1
var T1=FP8(A.getz()) // Z1
var T2=FP8(A.getz()) // Z1
T1.mul(B.gety()) // T1=Z1.Y2
T2.mul(B.getx()) // T2=Z1.X2
X1.sub(T2); X1.norm() // X1=X1-Z1.X2
Y1.sub(T1); Y1.norm() // Y1=Y1-Z1.Y2
T1.copy(X1) // T1=X1-Z1.X2
X1.tmul(Qy) // X1=(X1-Z1.X2).Ys
if CONFIG_CURVE.SEXTIC_TWIST == CONFIG_CURVE.M_TYPE {
X1.times_i()
}
T1.mul(B.gety()) // T1=(X1-Z1.X2).Y2
T2.copy(Y1) // T2=Y1-Z1.Y2
T2.mul(B.getx()) // T2=(Y1-Z1.Y2).X2
T2.sub(T1); T2.norm() // T2=(Y1-Z1.Y2).X2 - (X1-Z1.X2).Y2
Y1.tmul(Qx); Y1.neg(); Y1.norm() // Y1=-(Y1-Z1.Y2).Xs
a=FP16(X1,T2) // (X1-Z1.X2).Ys | (Y1-Z1.Y2).X2 - (X1-Z1.X2).Y2 | - (Y1-Z1.Y2).Xs
if CONFIG_CURVE.SEXTIC_TWIST == CONFIG_CURVE.D_TYPE {
b=FP16(Y1)
c=FP16(0)
} else {
b=FP16(0)
c=FP16(Y1); c.times_i()
}
A.add(B)
var res=FP48(a,b,c)
res.settype(FP48.SPARSER)
return res
}
static private func lbits(_ n3:inout BIG,_ n:inout BIG) -> Int
{
n.copy(BIG(ROM.CURVE_Bnx))
n3.copy(n)
n3.pmul(3)
n3.norm()
return n3.nbits()
}
static public func initmp() -> [FP48]
{
var r=[FP48]();
for _ in (0...CONFIG_CURVE.ATE_BITS-1).reversed() {
r.append(FP48(1))
}
return r
}
/* basic Miller loop */
static public func miller(_ r: [FP48]) -> FP48 {
var res=FP48(1)
for i in (1...CONFIG_CURVE.ATE_BITS-1).reversed() {
res.sqr()
res.ssmul(r[i])
}
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
res.conj();
}
res.ssmul(r[0])
return res
}
/* Accumulate another set of line functions for n-pairing */
static public func another(_ r: inout [FP48],_ P1: ECP8,_ Q1: ECP) {
var n = BIG();
var n3 = BIG();
// P is needed in affine form for line function, Q for (Qx,Qy) extraction
var P=ECP8(); P.copy(P1); P.affine()
var Q=ECP(); Q.copy(Q1); Q.affine()
let Qx=FP(Q.getx())
let Qy=FP(Q.gety())
var A=ECP8()
A.copy(P)
var NP=ECP8()
NP.copy(P)
NP.neg()
let nb=lbits(&n3,&n)
for i in (1...nb-2).reversed() {
var lv=linedbl(&A,Qx,Qy)
let bt=n3.bit(UInt(i))-n.bit(UInt(i))
if bt == 1 {
let lv2=lineadd(&A,P,Qx,Qy)
lv.smul(lv2)
}
if bt == -1 {
let lv2=lineadd(&A,NP,Qx,Qy)
lv.smul(lv2)
}
r[i].ssmul(lv)
}
}
// Optimal R-ate pairing
static public func ate(_ P1:ECP8,_ Q1:ECP) -> FP48
{
var n = BIG();
var n3 = BIG();
var lv:FP48
var P=ECP8(); P.copy(P1); P.affine()
var Q=ECP(); Q.copy(Q1); Q.affine()
let Qx=FP(Q.getx())
let Qy=FP(Q.gety())
var A=ECP8()
var r=FP48(1)
A.copy(P)
var NP=ECP8()
NP.copy(P)
NP.neg()
let nb=lbits(&n3,&n)
for i in (1...nb-2).reversed()
{
r.sqr()
lv=linedbl(&A,Qx,Qy)
let bt=n3.bit(UInt(i))-n.bit(UInt(i))
if bt == 1 {
let lv2=lineadd(&A,P,Qx,Qy)
lv.smul(lv2)
}
if bt == -1 {
let lv2=lineadd(&A,NP,Qx,Qy)
lv.smul(lv2)
}
r.ssmul(lv)
}
if CONFIG_CURVE.SIGN_OF_X == CONFIG_CURVE.NEGATIVEX {
r.conj()
}
return r
}
// Optimal R-ate double pairing e(P,Q).e(R,S)
static public func ate2(_ P1:ECP8,_ Q1:ECP,_ R1:ECP8,_ S1:ECP) -> FP48
{
var n = BIG();
var n3 = BIG();
var lv:FP48
var P=ECP8(); P.copy(P1); P.affine()
var Q=ECP(); Q.copy(Q1); Q.affine()
var R=ECP8(); R.copy(R1); R.affine()
var S=ECP(); S.copy(S1); S.affine()
let Qx=FP(Q.getx())
let Qy=FP(Q.gety())
let Sx=FP(S.getx())
let Sy=FP(S.gety())
var A=ECP8()
var B=ECP8()
var r=FP48(1)
A.copy(P)
B.copy(R)
var NP=ECP8()
NP.copy(P)
NP.neg()
var NR=ECP8()
NR.copy(R)
NR.neg()
let nb=lbits(&n3,&n)
for i in (1...nb-2).reversed()
{
r.sqr()
lv=linedbl(&A,Qx,Qy)
var lv2=linedbl(&B,Sx,Sy)
lv.smul(lv2)
r.ssmul(lv)
let bt=n3.bit(UInt(i))-n.bit(UInt(i))
if bt == 1 {
lv=lineadd(&A,P,Qx,Qy)
lv2=lineadd(&B,R,Sx,Sy)
lv.smul(lv2)
r.ssmul(lv)
}
if bt == -1 {
lv=lineadd(&A,NP,Qx,Qy)
lv2=lineadd(&B,NR,Sx,Sy)
lv.smul(lv2)
r.ssmul(lv)
}
}
if CONFIG_CURVE.SIGN_OF_X == CONFIG_CURVE.NEGATIVEX {
r.conj()
}
return r
}
// final exponentiation - keep separate for multi-pairings and to avoid thrashing stack
static public func fexp(_ m:FP48) -> FP48
{
let f=FP2(BIG(ROM.Fra),BIG(ROM.Frb));
var x=BIG(ROM.CURVE_Bnx)
var r=FP48(m)
// Easy part of final exp
var lv=FP48(r)
lv.inverse()
r.conj()
r.mul(lv)
lv.copy(r)
r.frob(f,8)
r.mul(lv)
// Hard part of final exp
var t7=FP48(r); t7.usqr()
var t1=t7.pow(x)
x.fshr(1)
var t2=t1.pow(x)
x.fshl(1)
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
var t3=FP48(t1); t3.conj()
t2.mul(t3)
t2.mul(r)
r.mul(t7)
t1.copy(t2.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,14)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,13)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,12)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,11)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,10)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,9)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,8)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t2); t3.conj()
t1.mul(t3)
t3.copy(t1);
t3.frob(f,7)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,6)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,5)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,4)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,3)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,2)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
t3.copy(t1)
t3.frob(f,1)
r.mul(t3)
t1.copy(t1.pow(x))
if CONFIG_CURVE.SIGN_OF_X==CONFIG_CURVE.NEGATIVEX {
t1.conj()
}
r.mul(t1)
t2.frob(f,15)
r.mul(t2)
r.reduce()
return r
}
// GLV method
static func glv(_ e:BIG) -> [BIG]
{
var u=[BIG]();
let q=BIG(ROM.CURVE_Order)
var x=BIG(ROM.CURVE_Bnx)
var x2=BIG.smul(x,x)
x.copy(BIG.smul(x2,x2))
x2.copy(BIG.smul(x,x))
u.append(BIG(e))
u[0].mod(x2)
u.append(BIG(e))
u[1].div(x2)
u[1].rsub(q)
return u
}
// Galbraith & Scott Method
static func gs(_ e:BIG) -> [BIG]
{
var u=[BIG]();
let q=BIG(ROM.CURVE_Order)
let x=BIG(ROM.CURVE_Bnx)
var w=BIG(e)
for i in 0 ..< 15
{
u.append(BIG(w))
u[i].mod(x)
w.div(x)
}
u.append(BIG(w))
if CONFIG_CURVE.SIGN_OF_X == CONFIG_CURVE.NEGATIVEX {
u[1].copy(BIG.modneg(u[1],q))
u[3].copy(BIG.modneg(u[3],q))
u[5].copy(BIG.modneg(u[5],q))
u[7].copy(BIG.modneg(u[7],q))
u[9].copy(BIG.modneg(u[9],q))
u[11].copy(BIG.modneg(u[11],q))
u[13].copy(BIG.modneg(u[13],q))
u[15].copy(BIG.modneg(u[15],q))
}
return u
}
// Multiply P by e in group G1
static public func G1mul(_ P:ECP,_ e:BIG) -> ECP
{
var R:ECP
if (CONFIG_CURVE.USE_GLV)
{
R=ECP()
R.copy(P)
var Q=ECP()
Q.copy(P); Q.affine()
let q=BIG(ROM.CURVE_Order)
let cru=FP(BIG(ROM.CURVE_Cru))
var t=BIG(0)
var u=PAIR256.glv(e)
Q.mulx(cru);
var np=u[0].nbits()
t.copy(BIG.modneg(u[0],q))
var nn=t.nbits()
if (nn<np)
{
u[0].copy(t)
R.neg()
}
np=u[1].nbits()
t.copy(BIG.modneg(u[1],q))
nn=t.nbits()
if (nn<np)
{
u[1].copy(t)
Q.neg()
}
u[0].norm()
u[1].norm()
R=R.mul2(u[0],Q,u[1])
}
else
{
R=P.mul(e)
}
return R
}
// Multiply P by e in group G2
static public func G2mul(_ P:ECP8,_ e:BIG) -> ECP8
{
var R:ECP8
if (CONFIG_CURVE.USE_GS_G2)
{
var Q=[ECP8]()
let F=ECP8.frob_constants()
let q=BIG(ROM.CURVE_Order);
var u=PAIR256.gs(e);
var t=BIG(0)
Q.append(ECP8())
Q[0].copy(P);
for i in 1 ..< 16
{
Q.append(ECP8()); Q[i].copy(Q[i-1]);
Q[i].frob(F,1);
}
for i in 0 ..< 16
{
let np=u[i].nbits()
t.copy(BIG.modneg(u[i],q))
let nn=t.nbits()
if (nn<np)
{
u[i].copy(t)
Q[i].neg()
}
u[i].norm()
}
R=ECP8.mul16(Q,u)
}
else
{
R=P.mul(e)
}
return R;
}
// f=f^e
// Note that this method requires a lot of RAM! Better to use compressed XTR method, see FP16.swift
static public func GTpow(_ d:FP48,_ e:BIG) -> FP48
{
var r:FP48
if (CONFIG_CURVE.USE_GS_GT)
{
var g=[FP48]()
let f=FP2(BIG(ROM.Fra),BIG(ROM.Frb))
let q=BIG(ROM.CURVE_Order)
var t=BIG(0)
var u=gs(e)
g.append(FP48(0))
g[0].copy(d);
for i in 1 ..< 16
{
g.append(FP48(0)); g[i].copy(g[i-1])
g[i].frob(f,1)
}
for i in 0 ..< 16
{
let np=u[i].nbits()
t.copy(BIG.modneg(u[i],q))
let nn=t.nbits()
if (nn<np)
{
u[i].copy(t)
g[i].conj()
}
u[i].norm()
}
r=FP48.pow16(g,u)
}
else
{
r=d.pow(e)
}
return r
}
}