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3 lines
3.2 KiB
3 lines
3.2 KiB
/*! (c) Stefan Thomas | https://github.com/bitcoinjs/bitcoinjs-lib |
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*/ |
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ECFieldElementFp.prototype.getByteLength=function(){return Math.floor((this.toBigInteger().bitLength()+7)/8)};ECPointFp.prototype.getEncoded=function(c){var d=function(h,f){var g=h.toByteArrayUnsigned();if(f<g.length){g=g.slice(g.length-f)}else{while(f>g.length){g.unshift(0)}}return g};var a=this.getX().toBigInteger();var e=this.getY().toBigInteger();var b=d(a,32);if(c){if(e.isEven()){b.unshift(2)}else{b.unshift(3)}}else{b.unshift(4);b=b.concat(d(e,32))}return b};ECPointFp.decodeFrom=function(g,c){var f=c[0];var e=c.length-1;var d=c.slice(1,1+e/2);var b=c.slice(1+e/2,1+e);d.unshift(0);b.unshift(0);var a=new BigInteger(d);var h=new BigInteger(b);return new ECPointFp(g,g.fromBigInteger(a),g.fromBigInteger(h))};ECPointFp.decodeFromHex=function(g,c){var f=c.substr(0,2);var e=c.length-2;var d=c.substr(2,e/2);var b=c.substr(2+e/2,e/2);var a=new BigInteger(d,16);var h=new BigInteger(b,16);return new ECPointFp(g,g.fromBigInteger(a),g.fromBigInteger(h))};ECPointFp.prototype.add2D=function(c){if(this.isInfinity()){return c}if(c.isInfinity()){return this}if(this.x.equals(c.x)){if(this.y.equals(c.y)){return this.twice()}return this.curve.getInfinity()}var g=c.x.subtract(this.x);var e=c.y.subtract(this.y);var a=e.divide(g);var d=a.square().subtract(this.x).subtract(c.x);var f=a.multiply(this.x.subtract(d)).subtract(this.y);return new ECPointFp(this.curve,d,f)};ECPointFp.prototype.twice2D=function(){if(this.isInfinity()){return this}if(this.y.toBigInteger().signum()==0){return this.curve.getInfinity()}var b=this.curve.fromBigInteger(BigInteger.valueOf(2));var e=this.curve.fromBigInteger(BigInteger.valueOf(3));var a=this.x.square().multiply(e).add(this.curve.a).divide(this.y.multiply(b));var c=a.square().subtract(this.x.multiply(b));var d=a.multiply(this.x.subtract(c)).subtract(this.y);return new ECPointFp(this.curve,c,d)};ECPointFp.prototype.multiply2D=function(b){if(this.isInfinity()){return this}if(b.signum()==0){return this.curve.getInfinity()}var g=b;var f=g.multiply(new BigInteger("3"));var l=this.negate();var d=this;var c;for(c=f.bitLength()-2;c>0;--c){d=d.twice();var a=f.testBit(c);var j=g.testBit(c);if(a!=j){d=d.add2D(a?this:l)}}return d};ECPointFp.prototype.isOnCurve=function(){var d=this.getX().toBigInteger();var i=this.getY().toBigInteger();var f=this.curve.getA().toBigInteger();var c=this.curve.getB().toBigInteger();var h=this.curve.getQ();var e=i.multiply(i).mod(h);var g=d.multiply(d).multiply(d).add(f.multiply(d)).add(c).mod(h);return e.equals(g)};ECPointFp.prototype.toString=function(){return"("+this.getX().toBigInteger().toString()+","+this.getY().toBigInteger().toString()+")"};ECPointFp.prototype.validate=function(){var c=this.curve.getQ();if(this.isInfinity()){throw new Error("Point is at infinity.")}var a=this.getX().toBigInteger();var b=this.getY().toBigInteger();if(a.compareTo(BigInteger.ONE)<0||a.compareTo(c.subtract(BigInteger.ONE))>0){throw new Error("x coordinate out of bounds")}if(b.compareTo(BigInteger.ONE)<0||b.compareTo(c.subtract(BigInteger.ONE))>0){throw new Error("y coordinate out of bounds")}if(!this.isOnCurve()){throw new Error("Point is not on the curve.")}if(this.multiply(c).isInfinity()){throw new Error("Point is not a scalar multiple of G.")}return true}; |