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