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@ -9,42 +9,42 @@ var BigInteger = require('bigi') |
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var THREE = BigInteger.valueOf(3) |
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function ECFieldElementFp(q,x) { |
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this.x = x; |
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// TODO if(x.compareTo(q) >= 0) error
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this.q = q; |
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this.x = x; |
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// TODO if (x.compareTo(q) >= 0) error
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this.q = q; |
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} |
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function feFpEquals(other) { |
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if(other == this) return true; |
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return (this.q.equals(other.q) && this.x.equals(other.x)); |
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if (other == this) return true; |
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return (this.q.equals(other.q) && this.x.equals(other.x)); |
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} |
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function feFpToBigInteger() { |
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return this.x; |
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return this.x; |
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} |
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function feFpNegate() { |
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return new ECFieldElementFp(this.q, this.x.negate().mod(this.q)); |
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return new ECFieldElementFp(this.q, this.x.negate().mod(this.q)); |
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} |
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function feFpAdd(b) { |
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return new ECFieldElementFp(this.q, this.x.add(b.toBigInteger()).mod(this.q)); |
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return new ECFieldElementFp(this.q, this.x.add(b.toBigInteger()).mod(this.q)); |
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} |
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function feFpSubtract(b) { |
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return new ECFieldElementFp(this.q, this.x.subtract(b.toBigInteger()).mod(this.q)); |
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return new ECFieldElementFp(this.q, this.x.subtract(b.toBigInteger()).mod(this.q)); |
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} |
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function feFpMultiply(b) { |
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return new ECFieldElementFp(this.q, this.x.multiply(b.toBigInteger()).mod(this.q)); |
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return new ECFieldElementFp(this.q, this.x.multiply(b.toBigInteger()).mod(this.q)); |
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} |
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function feFpSquare() { |
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return new ECFieldElementFp(this.q, this.x.square().mod(this.q)); |
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return new ECFieldElementFp(this.q, this.x.square().mod(this.q)); |
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} |
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function feFpDivide(b) { |
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return new ECFieldElementFp(this.q, this.x.multiply(b.toBigInteger().modInverse(this.q)).mod(this.q)); |
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return new ECFieldElementFp(this.q, this.x.multiply(b.toBigInteger().modInverse(this.q)).mod(this.q)); |
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} |
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ECFieldElementFp.prototype.equals = feFpEquals; |
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@ -61,151 +61,156 @@ ECFieldElementFp.prototype.divide = feFpDivide; |
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// constructor
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function ECPointFp(curve,x,y,z) { |
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this.curve = curve; |
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this.x = x; |
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this.y = y; |
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// Projective coordinates: either zinv == null or z * zinv == 1
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// z and zinv are just BigIntegers, not fieldElements
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if(z == null) { |
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this.z = BigInteger.ONE; |
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} |
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else { |
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this.z = z; |
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} |
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this.zinv = null; |
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//TODO: compression flag
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this.curve = curve; |
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this.x = x; |
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this.y = y; |
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// Projective coordinates: either zinv == null or z * zinv == 1
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// z and zinv are just BigIntegers, not fieldElements
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if (z == null) { |
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this.z = BigInteger.ONE; |
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} |
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else { |
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this.z = z; |
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} |
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this.zinv = null; |
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//TODO: compression flag
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} |
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function pointFpGetX() { |
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if(this.zinv == null) { |
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this.zinv = this.z.modInverse(this.curve.q); |
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} |
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return this.curve.fromBigInteger(this.x.toBigInteger().multiply(this.zinv).mod(this.curve.q)); |
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if (this.zinv == null) { |
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this.zinv = this.z.modInverse(this.curve.q); |
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} |
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return this.curve.fromBigInteger(this.x.toBigInteger().multiply(this.zinv).mod(this.curve.q)); |
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} |
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function pointFpGetY() { |
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if(this.zinv == null) { |
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this.zinv = this.z.modInverse(this.curve.q); |
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} |
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return this.curve.fromBigInteger(this.y.toBigInteger().multiply(this.zinv).mod(this.curve.q)); |
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if (this.zinv == null) { |
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this.zinv = this.z.modInverse(this.curve.q); |
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} |
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return this.curve.fromBigInteger(this.y.toBigInteger().multiply(this.zinv).mod(this.curve.q)); |
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} |
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function pointFpEquals(other) { |
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if(other == this) return true; |
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if(this.isInfinity()) return other.isInfinity(); |
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if(other.isInfinity()) return this.isInfinity(); |
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var u, v; |
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// u = Y2 * Z1 - Y1 * Z2
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u = other.y.toBigInteger().multiply(this.z).subtract(this.y.toBigInteger().multiply(other.z)).mod(this.curve.q); |
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if (u.signum() !== 0) return false; |
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// v = X2 * Z1 - X1 * Z2
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v = other.x.toBigInteger().multiply(this.z).subtract(this.x.toBigInteger().multiply(other.z)).mod(this.curve.q); |
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return v.signum() === 0; |
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if (other == this) return true; |
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if (this.isInfinity()) return other.isInfinity(); |
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if (other.isInfinity()) return this.isInfinity(); |
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var u, v; |
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// u = Y2 * Z1 - Y1 * Z2
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u = other.y.toBigInteger().multiply(this.z).subtract(this.y.toBigInteger().multiply(other.z)).mod(this.curve.q); |
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if (u.signum() !== 0) return false; |
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// v = X2 * Z1 - X1 * Z2
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v = other.x.toBigInteger().multiply(this.z).subtract(this.x.toBigInteger().multiply(other.z)).mod(this.curve.q); |
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return v.signum() === 0; |
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} |
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function pointFpIsInfinity() { |
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if ((this.x == null) && (this.y == null)) return true; |
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return this.z.signum() === 0 && this.y.toBigInteger().signum() !== 0; |
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if ((this.x == null) && (this.y == null)) return true; |
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return this.z.signum() === 0 && this.y.toBigInteger().signum() !== 0; |
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} |
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function pointFpNegate() { |
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return new ECPointFp(this.curve, this.x, this.y.negate(), this.z); |
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return new ECPointFp(this.curve, this.x, this.y.negate(), this.z); |
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} |
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function pointFpAdd(b) { |
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if(this.isInfinity()) return b; |
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if(b.isInfinity()) return this; |
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var x1 = this.x.toBigInteger() |
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var y1 = this.y.toBigInteger() |
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var x2 = b.x.toBigInteger() |
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var y2 = b.y.toBigInteger() |
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// u = Y2 * Z1 - Y1 * Z2
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var u = y2.multiply(this.z).subtract(y1.multiply(b.z)).mod(this.curve.q) |
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// v = X2 * Z1 - X1 * Z2
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var v = x2.multiply(this.z).subtract(x1.multiply(b.z)).mod(this.curve.q) |
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if(v.signum() === 0) { |
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if(u.signum() === 0) { |
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return this.twice(); // this == b, so double
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} |
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return this.curve.getInfinity(); // this = -b, so infinity
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} |
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if (this.isInfinity()) return b; |
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if (b.isInfinity()) return this; |
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var x1 = this.x.toBigInteger() |
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var y1 = this.y.toBigInteger() |
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var x2 = b.x.toBigInteger() |
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var y2 = b.y.toBigInteger() |
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// u = Y2 * Z1 - Y1 * Z2
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var u = y2.multiply(this.z).subtract(y1.multiply(b.z)).mod(this.curve.q) |
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// v = X2 * Z1 - X1 * Z2
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var v = x2.multiply(this.z).subtract(x1.multiply(b.z)).mod(this.curve.q) |
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if (v.signum() === 0) { |
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if (u.signum() === 0) { |
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return this.twice(); // this == b, so double
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} |
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return this.curve.getInfinity(); // this = -b, so infinity
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} |
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var v2 = v.square(); |
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var v3 = v2.multiply(v); |
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var x1v2 = x1.multiply(v2); |
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var zu2 = u.square().multiply(this.z); |
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var v2 = v.square(); |
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var v3 = v2.multiply(v); |
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var x1v2 = x1.multiply(v2); |
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var zu2 = u.square().multiply(this.z); |
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// x3 = v * (z2 * (z1 * u^2 - 2 * x1 * v^2) - v^3)
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var x3 = zu2.subtract(x1v2.shiftLeft(1)).multiply(b.z).subtract(v3).multiply(v).mod(this.curve.q); |
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// y3 = z2 * (3 * x1 * u * v^2 - y1 * v^3 - z1 * u^3) + u * v^3
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var y3 = x1v2.multiply(THREE).multiply(u).subtract(y1.multiply(v3)).subtract(zu2.multiply(u)).multiply(b.z).add(u.multiply(v3)).mod(this.curve.q); |
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// z3 = v^3 * z1 * z2
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var z3 = v3.multiply(this.z).multiply(b.z).mod(this.curve.q); |
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// x3 = v * (z2 * (z1 * u^2 - 2 * x1 * v^2) - v^3)
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var x3 = zu2.subtract(x1v2.shiftLeft(1)).multiply(b.z).subtract(v3).multiply(v).mod(this.curve.q); |
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// y3 = z2 * (3 * x1 * u * v^2 - y1 * v^3 - z1 * u^3) + u * v^3
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var y3 = x1v2.multiply(THREE).multiply(u).subtract(y1.multiply(v3)).subtract(zu2.multiply(u)).multiply(b.z).add(u.multiply(v3)).mod(this.curve.q); |
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// z3 = v^3 * z1 * z2
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var z3 = v3.multiply(this.z).multiply(b.z).mod(this.curve.q); |
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return new ECPointFp(this.curve, this.curve.fromBigInteger(x3), this.curve.fromBigInteger(y3), z3); |
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return new ECPointFp(this.curve, this.curve.fromBigInteger(x3), this.curve.fromBigInteger(y3), z3); |
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} |
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function pointFpTwice() { |
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if(this.isInfinity()) return this; |
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if(this.y.toBigInteger().signum() === 0) return this.curve.getInfinity(); |
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if (this.isInfinity()) return this; |
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if (this.y.toBigInteger().signum() === 0) return this.curve.getInfinity(); |
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var x1 = this.x.toBigInteger(); |
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var y1 = this.y.toBigInteger(); |
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var x1 = this.x.toBigInteger(); |
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var y1 = this.y.toBigInteger(); |
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var y1z1 = y1.multiply(this.z); |
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var y1sqz1 = y1z1.multiply(y1).mod(this.curve.q); |
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var a = this.curve.a.toBigInteger(); |
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var y1z1 = y1.multiply(this.z); |
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var y1sqz1 = y1z1.multiply(y1).mod(this.curve.q); |
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var a = this.curve.a.toBigInteger(); |
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// w = 3 * x1^2 + a * z1^2
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var w = x1.square().multiply(THREE); |
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if(a.signum() !== 0) { |
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w = w.add(this.z.square().multiply(a)); |
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} |
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w = w.mod(this.curve.q); |
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// x3 = 2 * y1 * z1 * (w^2 - 8 * x1 * y1^2 * z1)
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var x3 = w.square().subtract(x1.shiftLeft(3).multiply(y1sqz1)).shiftLeft(1).multiply(y1z1).mod(this.curve.q); |
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// y3 = 4 * y1^2 * z1 * (3 * w * x1 - 2 * y1^2 * z1) - w^3
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var y3 = w.multiply(THREE).multiply(x1).subtract(y1sqz1.shiftLeft(1)).shiftLeft(2).multiply(y1sqz1).subtract(w.pow(3)).mod(this.curve.q); |
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// z3 = 8 * (y1 * z1)^3
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var z3 = y1z1.pow(3).shiftLeft(3).mod(this.curve.q); |
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return new ECPointFp(this.curve, this.curve.fromBigInteger(x3), this.curve.fromBigInteger(y3), z3); |
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// w = 3 * x1^2 + a * z1^2
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var w = x1.square().multiply(THREE); |
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if (a.signum() !== 0) { |
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w = w.add(this.z.square().multiply(a)); |
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} |
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w = w.mod(this.curve.q); |
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// x3 = 2 * y1 * z1 * (w^2 - 8 * x1 * y1^2 * z1)
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var x3 = w.square().subtract(x1.shiftLeft(3).multiply(y1sqz1)).shiftLeft(1).multiply(y1z1).mod(this.curve.q); |
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// y3 = 4 * y1^2 * z1 * (3 * w * x1 - 2 * y1^2 * z1) - w^3
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var y3 = w.multiply(THREE).multiply(x1).subtract(y1sqz1.shiftLeft(1)).shiftLeft(2).multiply(y1sqz1).subtract(w.pow(3)).mod(this.curve.q); |
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// z3 = 8 * (y1 * z1)^3
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var z3 = y1z1.pow(3).shiftLeft(3).mod(this.curve.q); |
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return new ECPointFp(this.curve, this.curve.fromBigInteger(x3), this.curve.fromBigInteger(y3), z3); |
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} |
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// Simple NAF (Non-Adjacent Form) multiplication algorithm
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// TODO: modularize the multiplication algorithm
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function pointFpMultiply(k) { |
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if(this.isInfinity()) return this; |
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if(k.signum() === 0) return this.curve.getInfinity() |
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if (this.isInfinity()) return this; |
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if (k.signum() === 0) return this.curve.getInfinity() |
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var e = k; |
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var h = e.multiply(THREE) |
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var e = k; |
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var h = e.multiply(THREE) |
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var neg = this.negate(); |
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var R = this; |
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var neg = this.negate(); |
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var R = this; |
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var i; |
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for(i = h.bitLength() - 2; i > 0; --i) { |
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R = R.twice(); |
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var i; |
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for(i = h.bitLength() - 2; i > 0; --i) { |
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R = R.twice(); |
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var hBit = h.testBit(i); |
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var eBit = e.testBit(i); |
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var hBit = h.testBit(i); |
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var eBit = e.testBit(i); |
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if (hBit != eBit) { |
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R = R.add(hBit ? this : neg); |
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} |
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if (hBit != eBit) { |
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R = R.add(hBit ? this : neg); |
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} |
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} |
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return R; |
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return R; |
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} |
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// Compute this*j + x*k (simultaneous multiplication)
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function pointFpMultiplyTwo(j,x,k) { |
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var i; |
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if(j.bitLength() > k.bitLength()) |
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if (j.bitLength() > k.bitLength()) |
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i = j.bitLength() - 1; |
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else |
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i = k.bitLength() - 1; |
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@ -214,8 +219,8 @@ function pointFpMultiplyTwo(j,x,k) { |
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var both = this.add(x); |
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while(i >= 0) { |
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R = R.twice(); |
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if(j.testBit(i)) { |
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if(k.testBit(i)) { |
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if (j.testBit(i)) { |
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if (k.testBit(i)) { |
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R = R.add(both); |
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} |
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else { |
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@ -223,7 +228,7 @@ function pointFpMultiplyTwo(j,x,k) { |
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} |
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} |
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else { |
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if(k.testBit(i)) { |
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if (k.testBit(i)) { |
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R = R.add(x); |
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} |
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} |
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@ -248,35 +253,35 @@ ECPointFp.prototype.multiplyTwo = pointFpMultiplyTwo; |
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// constructor
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function ECCurveFp(q,a,b) { |
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this.q = q; |
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this.a = this.fromBigInteger(a); |
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this.b = this.fromBigInteger(b); |
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this.infinity = new ECPointFp(this, null, null); |
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this.q = q; |
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this.a = this.fromBigInteger(a); |
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this.b = this.fromBigInteger(b); |
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this.infinity = new ECPointFp(this, null, null); |
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} |
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function curveFpGetQ() { |
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return this.q; |
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return this.q; |
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} |
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function curveFpGetA() { |
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return this.a; |
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return this.a; |
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} |
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function curveFpGetB() { |
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return this.b; |
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return this.b; |
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} |
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function curveFpEquals(other) { |
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if(other == this) return true; |
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return(this.q.equals(other.q) && this.a.equals(other.a) && this.b.equals(other.b)); |
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if (other == this) return true; |
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return(this.q.equals(other.q) && this.a.equals(other.a) && this.b.equals(other.b)); |
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} |
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function curveFpGetInfinity() { |
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return this.infinity; |
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return this.infinity; |
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} |
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function curveFpFromBigInteger(x) { |
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return new ECFieldElementFp(this.q, x); |
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return new ECFieldElementFp(this.q, x); |
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} |
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ECCurveFp.prototype.getQ = curveFpGetQ; |
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@ -410,6 +415,5 @@ ECPointFp.prototype.validate = function () { |
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return true; |
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}; |
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module.exports = ECCurveFp; |
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module.exports.ECPointFp = ECPointFp; |
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