57 lines
1.7 KiB
JavaScript
57 lines
1.7 KiB
JavaScript
var crypto = require("crypto");
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var BigInteger = require("jsbn").BigInteger;
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var ECPointFp = require("./lib/ec.js").ECPointFp;
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exports.ECCurves = require("./lib/sec.js");
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// zero prepad
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function unstupid(hex,len)
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{
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return (hex.length >= len) ? hex : unstupid("0"+hex,len);
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}
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exports.ECKey = function(curve, key, isPublic)
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{
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var priv;
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var c = curve();
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var n = c.getN();
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var bytes = Math.floor(n.bitLength()/8);
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if(key)
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{
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if(isPublic)
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{
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var curve = c.getCurve();
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// var x = key.slice(1,bytes+1); // skip the 04 for uncompressed format
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// var y = key.slice(bytes+1);
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// this.P = new ECPointFp(curve,
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// curve.fromBigInteger(new BigInteger(x.toString("hex"), 16)),
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// curve.fromBigInteger(new BigInteger(y.toString("hex"), 16)));
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this.P = curve.decodePointHex(key.toString("hex"));
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}else{
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if(key.length != bytes) return false;
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priv = new BigInteger(key.toString("hex"), 16);
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}
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}else{
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var n1 = n.subtract(BigInteger.ONE);
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var r = new BigInteger(crypto.randomBytes(n.bitLength()));
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priv = r.mod(n1).add(BigInteger.ONE);
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this.P = c.getG().multiply(priv);
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}
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if(this.P)
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{
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// var pubhex = unstupid(this.P.getX().toBigInteger().toString(16),bytes*2)+unstupid(this.P.getY().toBigInteger().toString(16),bytes*2);
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// this.PublicKey = new Buffer("04"+pubhex,"hex");
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this.PublicKey = new Buffer(c.getCurve().encodeCompressedPointHex(this.P),"hex");
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}
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if(priv)
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{
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this.PrivateKey = new Buffer(unstupid(priv.toString(16),bytes*2),"hex");
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this.deriveSharedSecret = function(key)
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{
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if(!key || !key.P) return false;
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var S = key.P.multiply(priv);
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return new Buffer(unstupid(S.getX().toBigInteger().toString(16),bytes*2),"hex");
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}
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}
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}
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