/*
 Coinjs 0.01 beta by OutCast3k{at}gmail.com
 A bitcoin framework.

 http://github.com/OutCast3k/coinjs or http://coinb.in/coinjs
*/

(function () {

	var coinjs = window.coinjs = function () { };

	/* public vars */
	coinjs.pub = 0x00;
	coinjs.priv = 0x80;
	coinjs.multisig = 0x05;
	coinjs.hdkey = {'prv':0x0488ade4, 'pub':0x0488b21e};

	coinjs.compressed = false;

	/* other vars */
	coinjs.developer = '1CWHWkTWaq1K5hevimJia3cyinQsrgXUvg'; // bitcoin

	/* bit(coinb.in) api vars */
	coinjs.host = ('https:'==document.location.protocol?'https://':'http://')+'coinb.in/api/';
	coinjs.uid = '1';
	coinjs.key = '12345678901234567890123456789012';

	/* start of address functions */

	/* generate a private and public keypair, with address and WIF address */
	coinjs.newKeys = function(input){
		var privkey = (input) ? Crypto.SHA256(input) : this.newPrivkey();
		var pubkey = this.newPubkey(privkey);
		return {
			'privkey': privkey,
			'pubkey': pubkey,
			'address': this.pubkey2address(pubkey),
			'wif': this.privkey2wif(privkey),
			'compressed': this.compressed
		};
	}

	/* generate a new random private key */
	coinjs.newPrivkey = function(){
		var x = window.location;
		x += (window.screen.height * window.screen.width * window.screen.colorDepth);
		x += coinjs.random(64);
		x += (window.screen.availHeight * window.screen.availWidth * window.screen.pixelDepth);
		x += navigator.language;
		x += window.history.length;
		x += coinjs.random(64);
		x += navigator.userAgent;
		x += 'coinb.in';
		x += (Crypto.util.randomBytes(64)).join("");
		x += x.length;
		var dateObj = new Date();
		x += dateObj.getTimezoneOffset();
		x += coinjs.random(64);
		x += (document.getElementById("entropybucket")) ? document.getElementById("entropybucket").innerHTML : '';
		x += x+''+x;
		var r = x;
		for(i=0;i<(x).length/25;i++){
			r = Crypto.SHA256(r.concat(x));
		}
		var checkrBigInt = new BigInteger(r);
		var orderBigInt = new BigInteger("fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141");
		while (checkrBigInt.compareTo(orderBigInt) >= 0 || checkrBigInt.equals(BigInteger.ZERO) || checkrBigInt.equals(BigInteger.ONE)) {
			r = Crypto.SHA256(r.concat(x));
			checkrBigInt = new BigInteger(r);
		}
		return r;
	}

	/* generate a public key from a private key */
	coinjs.newPubkey = function(hash){
		var privateKeyBigInt = BigInteger.fromByteArrayUnsigned(Crypto.util.hexToBytes(hash));
		var curve = EllipticCurve.getSECCurveByName("secp256k1");

		var curvePt = curve.getG().multiply(privateKeyBigInt);
		var x = curvePt.getX().toBigInteger();
		var y = curvePt.getY().toBigInteger();

		var publicKeyBytes = EllipticCurve.integerToBytes(x, 32);
		publicKeyBytes = publicKeyBytes.concat(EllipticCurve.integerToBytes(y,32));
		publicKeyBytes.unshift(0x04);

		if(coinjs.compressed==true){
			var publicKeyBytesCompressed = EllipticCurve.integerToBytes(x,32)
			if (y.isEven()){
				publicKeyBytesCompressed.unshift(0x02)
			} else {
				publicKeyBytesCompressed.unshift(0x03)
			}
			return Crypto.util.bytesToHex(publicKeyBytesCompressed);
		} else {
			return Crypto.util.bytesToHex(publicKeyBytes);
		}
	}

	/* provide a public key and return address */
	coinjs.pubkey2address = function(h, byte){
		var r = ripemd160(Crypto.SHA256(Crypto.util.hexToBytes(h), {asBytes: true}));
		r.unshift(byte || coinjs.pub);
		var hash = Crypto.SHA256(Crypto.SHA256(r, {asBytes: true}), {asBytes: true});
		var checksum = hash.slice(0, 4);
		return coinjs.base58encode(r.concat(checksum));
	}

	/* provide a scripthash and return address */
	coinjs.scripthash2address = function(h){
		var x = Crypto.util.hexToBytes(h);
		x.unshift(coinjs.pub);
		var r = x;
		r = Crypto.SHA256(Crypto.SHA256(r,{asBytes: true}),{asBytes: true});
		var checksum = r.slice(0,4);
		return coinjs.base58encode(x.concat(checksum));
	}

	/* new multisig address, provide the pubkeys AND required signatures to release the funds */
	coinjs.pubkeys2MultisigAddress = function(pubkeys, required) {
		var s = coinjs.script();
		s.writeOp(81 + (required*1) - 1); //OP_1
		for (var i = 0; i < pubkeys.length; ++i) {
			s.writeBytes(Crypto.util.hexToBytes(pubkeys[i]));
		}
		s.writeOp(81 + pubkeys.length - 1); //OP_1 
		s.writeOp(174); //OP_CHECKMULTISIG
		var x = ripemd160(Crypto.SHA256(s.buffer, {asBytes: true}), {asBytes: true});
		x.unshift(coinjs.multisig);
		var r = x;
		r = Crypto.SHA256(Crypto.SHA256(r, {asBytes: true}), {asBytes: true});
		var checksum = r.slice(0,4);
		var redeemScript = Crypto.util.bytesToHex(s.buffer);
		var address = coinjs.base58encode(x.concat(checksum));
		return {'address':address, 'redeemScript':redeemScript};
	}

	/* new time locked address, provide the pubkey and time necessary to unlock the funds.
	   when time is greater than 500000000, it should be a unix timestamp (seconds since epoch),
	   otherwise it should be the block height required before this transaction can be released. 

	   may throw a string on failure!
	*/
	coinjs.simpleHodlAddress = function(pubkey, checklocktimeverify) {

		if(checklocktimeverify < 0) {
			throw "Parameter for OP_CHECKLOCKTIMEVERIFY is negative.";
		}

		var s = coinjs.script();
		s.writeBytes(coinjs.numToByteArray(checklocktimeverify));
		s.writeOp(177);//OP_CHECKLOCKTIMEVERIFY
		s.writeOp(117);//OP_DROP
		s.writeBytes(Crypto.util.hexToBytes(pubkey));
		s.writeOp(172);//OP_CHECKSIG

		var x = ripemd160(Crypto.SHA256(s.buffer, {asBytes: true}), {asBytes: true});
		x.unshift(coinjs.multisig);
		var r = x;
		r = Crypto.SHA256(Crypto.SHA256(r, {asBytes: true}), {asBytes: true});
		var checksum = r.slice(0,4);
		var redeemScript = Crypto.util.bytesToHex(s.buffer);
		var address = coinjs.base58encode(x.concat(checksum));

		return {'address':address, 'redeemScript':redeemScript};
	}

	/* create a new segwit address */
	coinjs.segwitAddress = function(pubkey){
		var keyhash = [0x00,0x14].concat(ripemd160(Crypto.SHA256(Crypto.util.hexToBytes(pubkey), {asBytes: true}), {asBytes: true}));
		var x = ripemd160(Crypto.SHA256(keyhash, {asBytes: true}), {asBytes: true});
		x.unshift(coinjs.multisig);
		var r = x;
		r = Crypto.SHA256(Crypto.SHA256(r, {asBytes: true}), {asBytes: true});
		var checksum = r.slice(0,4);
		var address = coinjs.base58encode(x.concat(checksum));

		return {'address':address, 'type':'segwit', 'redeemscript':Crypto.util.bytesToHex(keyhash)};
	}

	/* provide a privkey and return an WIF  */
	coinjs.privkey2wif = function(h){
		var r = Crypto.util.hexToBytes(h);

		if(coinjs.compressed==true){
			r.push(0x01);
		}

		r.unshift(coinjs.priv);
		var hash = Crypto.SHA256(Crypto.SHA256(r, {asBytes: true}), {asBytes: true});
		var checksum = hash.slice(0, 4);

		return coinjs.base58encode(r.concat(checksum));
	}

	/* convert a wif key back to a private key */
	coinjs.wif2privkey = function(wif){
		var compressed = false;
		var decode = coinjs.base58decode(wif);
		var key = decode.slice(0, decode.length-4);
		key = key.slice(1, key.length);
		if(key.length>=33 && key[key.length-1]==0x01){
			key = key.slice(0, key.length-1);
			compressed = true;
		}
		return {'privkey': Crypto.util.bytesToHex(key), 'compressed':compressed};
	}

	/* convert a wif to a pubkey */
	coinjs.wif2pubkey = function(wif){
		var compressed = coinjs.compressed;
		var r = coinjs.wif2privkey(wif);
		coinjs.compressed = r['compressed'];
		var pubkey = coinjs.newPubkey(r['privkey']);
		coinjs.compressed = compressed;
		return {'pubkey':pubkey,'compressed':r['compressed']};
	}

	/* convert a wif to a address */
	coinjs.wif2address = function(wif){
		var r = coinjs.wif2pubkey(wif);
		return {'address':coinjs.pubkey2address(r['pubkey']), 'compressed':r['compressed']};
	}

	/* decode or validate an address and return the hash */
	coinjs.addressDecode = function(addr){
		try {
			var bytes = coinjs.base58decode(addr);
			var front = bytes.slice(0, bytes.length-4);
			var back = bytes.slice(bytes.length-4);
			var checksum = Crypto.SHA256(Crypto.SHA256(front, {asBytes: true}), {asBytes: true}).slice(0, 4);
			if (checksum+"" == back+"") {

				var o = {};
				o.bytes = front.slice(1);
				o.version = front[0];

				if(o.version==coinjs.pub){ // standard address
					o.type = 'standard';

				} else if (o.version==coinjs.multisig) { // multisig address
					o.type = 'multisig';

				} else if (o.version==coinjs.priv){ // wifkey
					o.type = 'wifkey';

				} else if (o.version==42) { // stealth address
					o.type = 'stealth';

					o.option = front[1];
					if (o.option != 0) {
						alert("Stealth Address option other than 0 is currently not supported!");
						return false;
					};

					o.scankey = Crypto.util.bytesToHex(front.slice(2, 35));
					o.n = front[35];

					if (o.n > 1) {
						alert("Stealth Multisig is currently not supported!");
						return false;
					};
				
					o.spendkey = Crypto.util.bytesToHex(front.slice(36, 69));
					o.m = front[69];
					o.prefixlen = front[70];
				
					if (o.prefixlen > 0) {
						alert("Stealth Address Prefixes are currently not supported!");
						return false;
					};
					o.prefix = front.slice(71);

				} else { // everything else
					o.type = 'other'; // address is still valid but unknown version
				}

				return o;
			} else {
				return false;
			}
		} catch(e) {
			return false;
		}
	}

	/* retreive the balance from a given address */
	coinjs.addressBalance = function(address, callback){
		coinjs.ajax(coinjs.host+'?uid='+coinjs.uid+'&key='+coinjs.key+'&setmodule=addresses&request=bal&address='+address+'&r='+Math.random(), callback, "GET");
	}

	/* decompress an compressed public key */
	coinjs.pubkeydecompress = function(pubkey) {
		if((typeof(pubkey) == 'string') && pubkey.match(/^[a-f0-9]+$/i)){
			var curve = EllipticCurve.getSECCurveByName("secp256k1");
			try {
				var pt = curve.curve.decodePointHex(pubkey);
				var x = pt.getX().toBigInteger();
				var y = pt.getY().toBigInteger();

				var publicKeyBytes = EllipticCurve.integerToBytes(x, 32);
				publicKeyBytes = publicKeyBytes.concat(EllipticCurve.integerToBytes(y,32));
				publicKeyBytes.unshift(0x04);
				return Crypto.util.bytesToHex(publicKeyBytes);
			} catch (e) {
				// console.log(e);
				return false;
			}
		}
		return false;
	}

	coinjs.testdeterministicK = function() {
		// https://github.com/bitpay/bitcore/blob/9a5193d8e94b0bd5b8e7f00038e7c0b935405a03/test/crypto/ecdsa.js
		// Line 21 and 22 specify digest hash and privkey for the first 2 test vectors.
		// Line 96-117 tells expected result.

		var tx = coinjs.transaction();

		var test_vectors = [
			{
				'message': 'test data',
				'privkey': 'fee0a1f7afebf9d2a5a80c0c98a31c709681cce195cbcd06342b517970c0be1e',
				'k_bad00': 'fcce1de7a9bcd6b2d3defade6afa1913fb9229e3b7ddf4749b55c4848b2a196e',
				'k_bad01': '727fbcb59eb48b1d7d46f95a04991fc512eb9dbf9105628e3aec87428df28fd8',
				'k_bad15': '398f0e2c9f79728f7b3d84d447ac3a86d8b2083c8f234a0ffa9c4043d68bd258'
			},
			{
				'message': 'Everything should be made as simple as possible, but not simpler.',
				'privkey': '0000000000000000000000000000000000000000000000000000000000000001',
				'k_bad00': 'ec633bd56a5774a0940cb97e27a9e4e51dc94af737596a0c5cbb3d30332d92a5',
				'k_bad01': 'df55b6d1b5c48184622b0ead41a0e02bfa5ac3ebdb4c34701454e80aabf36f56',
				'k_bad15': 'def007a9a3c2f7c769c75da9d47f2af84075af95cadd1407393dc1e26086ef87'
			},
			{
				'message': 'Satoshi Nakamoto',
				'privkey': '0000000000000000000000000000000000000000000000000000000000000002',
				'k_bad00': 'd3edc1b8224e953f6ee05c8bbf7ae228f461030e47caf97cde91430b4607405e',
				'k_bad01': 'f86d8e43c09a6a83953f0ab6d0af59fb7446b4660119902e9967067596b58374',
				'k_bad15': '241d1f57d6cfd2f73b1ada7907b199951f95ef5ad362b13aed84009656e0254a'
			},
			{
				'message': 'Diffie Hellman',
				'privkey': '7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f7f',
				'k_bad00': 'c378a41cb17dce12340788dd3503635f54f894c306d52f6e9bc4b8f18d27afcc',
				'k_bad01': '90756c96fef41152ac9abe08819c4e95f16da2af472880192c69a2b7bac29114',
				'k_bad15': '7b3f53300ab0ccd0f698f4d67db87c44cf3e9e513d9df61137256652b2e94e7c'
			},
			{
				'message': 'Japan',
				'privkey': '8080808080808080808080808080808080808080808080808080808080808080',
				'k_bad00': 'f471e61b51d2d8db78f3dae19d973616f57cdc54caaa81c269394b8c34edcf59',
				'k_bad01': '6819d85b9730acc876fdf59e162bf309e9f63dd35550edf20869d23c2f3e6d17',
				'k_bad15': 'd8e8bae3ee330a198d1f5e00ad7c5f9ed7c24c357c0a004322abca5d9cd17847'
			},
			{
				'message': 'Bitcoin',
				'privkey': 'fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364140',
				'k_bad00': '36c848ffb2cbecc5422c33a994955b807665317c1ce2a0f59c689321aaa631cc',
				'k_bad01': '4ed8de1ec952a4f5b3bd79d1ff96446bcd45cabb00fc6ca127183e14671bcb85',
				'k_bad15': '56b6f47babc1662c011d3b1f93aa51a6e9b5f6512e9f2e16821a238d450a31f8'
			},
			{
				'message': 'i2FLPP8WEus5WPjpoHwheXOMSobUJVaZM1JPMQZq',
				'privkey': 'fffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364140',
				'k_bad00': '6e9b434fcc6bbb081a0463c094356b47d62d7efae7da9c518ed7bac23f4e2ed6',
				'k_bad01': 'ae5323ae338d6117ce8520a43b92eacd2ea1312ae514d53d8e34010154c593bb',
				'k_bad15': '3eaa1b61d1b8ab2f1ca71219c399f2b8b3defa624719f1e96fe3957628c2c4ea'
			},
			{
				'message': 'lEE55EJNP7aLrMtjkeJKKux4Yg0E8E1SAJnWTCEh',
				'privkey': '3881e5286abc580bb6139fe8e83d7c8271c6fe5e5c2d640c1f0ed0e1ee37edc9',
				'k_bad00': '5b606665a16da29cc1c5411d744ab554640479dd8abd3c04ff23bd6b302e7034',
				'k_bad01': 'f8b25263152c042807c992eacd2ac2cc5790d1e9957c394f77ea368e3d9923bd',
				'k_bad15': 'ea624578f7e7964ac1d84adb5b5087dd14f0ee78b49072aa19051cc15dab6f33'
			},
			{
				'message': '2SaVPvhxkAPrayIVKcsoQO5DKA8Uv5X/esZFlf+y',
				'privkey': '7259dff07922de7f9c4c5720d68c9745e230b32508c497dd24cb95ef18856631',
				'k_bad00': '3ab6c19ab5d3aea6aa0c6da37516b1d6e28e3985019b3adb388714e8f536686b',
				'k_bad01': '19af21b05004b0ce9cdca82458a371a9d2cf0dc35a813108c557b551c08eb52e',
				'k_bad15': '117a32665fca1b7137a91c4739ac5719fec0cf2e146f40f8e7c21b45a07ebc6a'
			},
			{
				'message': '00A0OwO2THi7j5Z/jp0FmN6nn7N/DQd6eBnCS+/b',
				'privkey': '0d6ea45d62b334777d6995052965c795a4f8506044b4fd7dc59c15656a28f7aa',
				'k_bad00': '79487de0c8799158294d94c0eb92ee4b567e4dc7ca18addc86e49d31ce1d2db6',
				'k_bad01': '9561d2401164a48a8f600882753b3105ebdd35e2358f4f808c4f549c91490009',
				'k_bad15': 'b0d273634129ff4dbdf0df317d4062a1dbc58818f88878ffdb4ec511c77976c0'
			}
		];

		var result_txt = '\n----------------------\nResults\n----------------------\n\n';

		for (i = 0; i < test_vectors.length; i++) {
			var hash = Crypto.SHA256(test_vectors[i]['message'].split('').map(function (c) { return c.charCodeAt (0); }), { asBytes: true });
			var wif = coinjs.privkey2wif(test_vectors[i]['privkey']);

			var KBigInt = tx.deterministicK(wif, hash);
			var KBigInt0 = tx.deterministicK(wif, hash, 0);
			var KBigInt1 = tx.deterministicK(wif, hash, 1);
			var KBigInt15 = tx.deterministicK(wif, hash, 15);

			var K = Crypto.util.bytesToHex(KBigInt.toByteArrayUnsigned());
			var K0 = Crypto.util.bytesToHex(KBigInt0.toByteArrayUnsigned());
			var K1 = Crypto.util.bytesToHex(KBigInt1.toByteArrayUnsigned());
			var K15 = Crypto.util.bytesToHex(KBigInt15.toByteArrayUnsigned());

			if (K != test_vectors[i]['k_bad00']) {
				result_txt += 'Failed Test #' + (i + 1) + '\n       K = ' + K + '\nExpected = ' + test_vectors[i]['k_bad00'] + '\n\n';
			} else if (K0 != test_vectors[i]['k_bad00']) {
				result_txt += 'Failed Test #' + (i + 1) + '\n      K0 = ' + K0 + '\nExpected = ' + test_vectors[i]['k_bad00'] + '\n\n';
			} else if (K1 != test_vectors[i]['k_bad01']) {
				result_txt += 'Failed Test #' + (i + 1) + '\n      K1 = ' + K1 + '\nExpected = ' + test_vectors[i]['k_bad01'] + '\n\n';
			} else if (K15 != test_vectors[i]['k_bad15']) {
				result_txt += 'Failed Test #' + (i + 1) + '\n     K15 = ' + K15 + '\nExpected = ' + test_vectors[i]['k_bad15'] + '\n\n';
			};
		};

		if (result_txt.length < 60) {
			result_txt = 'All Tests OK!';
		};

		return result_txt;
	};

	/* start of hd functions, thanks bip32.org */
	coinjs.hd = function(data){

		var r = {};

		/* some hd value parsing */
		r.parse = function() {

			var bytes = [];

			// some quick validation
			if(typeof(data) == 'string'){
				var decoded = coinjs.base58decode(data);
				if(decoded.length == 82){
					var checksum = decoded.slice(78, 82);
					var hash = Crypto.SHA256(Crypto.SHA256(decoded.slice(0, 78), { asBytes: true } ), { asBytes: true } );
					if(checksum[0]==hash[0] && checksum[1]==hash[1] && checksum[2]==hash[2] && checksum[3]==hash[3]){
						bytes = decoded.slice(0, 78);
					}
				}
			}

			// actual parsing code
			if(bytes && bytes.length>0) {
 				r.version = coinjs.uint(bytes.slice(0, 4) , 4);
 				r.depth = coinjs.uint(bytes.slice(4, 5) ,1);
				r.parent_fingerprint = bytes.slice(5, 9);
				r.child_index = coinjs.uint(bytes.slice(9, 13), 4);
 				r.chain_code = bytes.slice(13, 45);
				r.key_bytes = bytes.slice(45, 78);

				var c = coinjs.compressed; // get current default
				coinjs.compressed = true;

				if(r.key_bytes[0] == 0x00) {
					r.type = 'private';
					var privkey = (r.key_bytes).slice(1, 33);
					var privkeyHex = Crypto.util.bytesToHex(privkey);
					var pubkey = coinjs.newPubkey(privkeyHex);

					r.keys = {'privkey':privkeyHex,
						'pubkey':pubkey,
						'address':coinjs.pubkey2address(pubkey),
						'wif':coinjs.privkey2wif(privkeyHex)};

				} else if(r.key_bytes[0] == 0x02 || r.key_bytes[0] == 0x03) {
					r.type = 'public';
					var pubkeyHex = Crypto.util.bytesToHex(r.key_bytes);

					r.keys = {'pubkey': pubkeyHex,
						'address':coinjs.pubkey2address(pubkeyHex)};
				} else {
					r.type = 'invalid';
				}

				r.keys_extended = r.extend();

				coinjs.compressed = c; // reset to default
			}
		}

		// extend prv/pub key
		r.extend = function(){
			var hd = coinjs.hd();
			return hd.make({'depth':(this.depth*1)+1,
				'parent_fingerprint':this.parent_fingerprint,
				'child_index':this.child_index,
				'chain_code':this.chain_code,
				'privkey':this.keys.privkey,
				'pubkey':this.keys.pubkey});
		}

		// derive key from index
		r.derive = function(i){
			i = (i)?i:0;
			var blob = (Crypto.util.hexToBytes(this.keys.pubkey)).concat(coinjs.numToBytes(i,4).reverse());

			var j = new jsSHA(Crypto.util.bytesToHex(blob), 'HEX');
 			var hash = j.getHMAC(Crypto.util.bytesToHex(r.chain_code), "HEX", "SHA-512", "HEX");

			var il = new BigInteger(hash.slice(0, 64), 16);
			var ir = Crypto.util.hexToBytes(hash.slice(64,128));

			var ecparams = EllipticCurve.getSECCurveByName("secp256k1");
			var curve = ecparams.getCurve();

			var k, key, pubkey, o;

			o = coinjs.clone(this);
			o.chain_code = ir;
			o.child_index = i;

			if(this.type=='private'){
				// derive key pair from from a xprv key
				k = il.add(new BigInteger([0].concat(Crypto.util.hexToBytes(this.keys.privkey)))).mod(ecparams.getN());
				key = Crypto.util.bytesToHex(k.toByteArrayUnsigned());

				pubkey = coinjs.newPubkey(key);

				o.keys = {'privkey':key,
					'pubkey':pubkey,
					'wif':coinjs.privkey2wif(key),
					'address':coinjs.pubkey2address(pubkey)};

			} else if (this.type=='public'){
				// derive xpub key from an xpub key
				q = ecparams.curve.decodePointHex(this.keys.pubkey);
				var curvePt = ecparams.getG().multiply(il).add(q);

				var x = curvePt.getX().toBigInteger();
				var y = curvePt.getY().toBigInteger();

				var publicKeyBytesCompressed = EllipticCurve.integerToBytes(x,32)
				if (y.isEven()){
					publicKeyBytesCompressed.unshift(0x02)
				} else {
					publicKeyBytesCompressed.unshift(0x03)
				}
				pubkey = Crypto.util.bytesToHex(publicKeyBytesCompressed);

				o.keys = {'pubkey':pubkey,
					'address':coinjs.pubkey2address(pubkey)}
			} else {
				// fail
			}

			o.parent_fingerprint = (ripemd160(Crypto.SHA256(Crypto.util.hexToBytes(r.keys.pubkey),{asBytes:true}),{asBytes:true})).slice(0,4);
			o.keys_extended = o.extend();

			return o;
		}

		// make a master hd xprv/xpub
		r.master = function(pass) {
			var seed = (pass) ? Crypto.SHA256(pass) : coinjs.newPrivkey();
			var hasher = new jsSHA(seed, 'HEX');
			var I = hasher.getHMAC("Bitcoin seed", "TEXT", "SHA-512", "HEX");

			var privkey = Crypto.util.hexToBytes(I.slice(0, 64));
			var chain = Crypto.util.hexToBytes(I.slice(64, 128));

			var hd = coinjs.hd();
			return hd.make({'depth':0,
				'parent_fingerprint':[0,0,0,0],
				'child_index':0,
				'chain_code':chain,
				'privkey':I.slice(0, 64),
				'pubkey':coinjs.newPubkey(I.slice(0, 64))});
		}

		// encode data to a base58 string
		r.make = function(data){ // { (int) depth, (array) parent_fingerprint, (int) child_index, (byte array) chain_code, (hex str) privkey, (hex str) pubkey}
			var k = [];

			//depth
			k.push(data.depth*1);

			//parent fingerprint
			k = k.concat(data.parent_fingerprint);

			//child index
			k = k.concat((coinjs.numToBytes(data.child_index, 4)).reverse());

			//Chain code
			k = k.concat(data.chain_code);

			var o = {}; // results

			//encode xprv key
			if(data.privkey){
				var prv = (coinjs.numToBytes(coinjs.hdkey.prv, 4)).reverse();
				prv = prv.concat(k);
				prv.push(0x00);
				prv = prv.concat(Crypto.util.hexToBytes(data.privkey));
				var hash = Crypto.SHA256( Crypto.SHA256(prv, { asBytes: true } ), { asBytes: true } );
				var checksum = hash.slice(0, 4);
				var ret = prv.concat(checksum);
				o.privkey = coinjs.base58encode(ret);
			}

			//encode xpub key
			if(data.pubkey){
				var pub = (coinjs.numToBytes(coinjs.hdkey.pub, 4)).reverse();
				pub = pub.concat(k);
				pub = pub.concat(Crypto.util.hexToBytes(data.pubkey));
				var hash = Crypto.SHA256( Crypto.SHA256(pub, { asBytes: true } ), { asBytes: true } );
				var checksum = hash.slice(0, 4);
				var ret = pub.concat(checksum);
				o.pubkey = coinjs.base58encode(ret);
			}
			return o;
		}

		r.parse();
		return r;
	}


	/* start of script functions */
	coinjs.script = function(data) {
		var r = {};

		if(!data){
			r.buffer = [];
		} else if ("string" == typeof data) {
			r.buffer = Crypto.util.hexToBytes(data);
		} else if (coinjs.isArray(data)) {
			r.buffer = data;
		} else if (data instanceof coinjs.script) {
			r.buffer = data.buffer;
		} else {
			r.buffer = data;
		}

		/* parse buffer array */
		r.parse = function () {

			var self = this;
			r.chunks = [];
			var i = 0;

			function readChunk(n) {
				self.chunks.push(self.buffer.slice(i, i + n));
				i += n;
			};

			while (i < this.buffer.length) {
				var opcode = this.buffer[i++];
				if (opcode >= 0xF0) {
 					opcode = (opcode << 8) | this.buffer[i++];
				}

				var len;
				if (opcode > 0 && opcode < 76) { //OP_PUSHDATA1
					readChunk(opcode);
				} else if (opcode == 76) { //OP_PUSHDATA1
					len = this.buffer[i++];
					readChunk(len);
				} else if (opcode == 77) { //OP_PUSHDATA2
 					len = (this.buffer[i++] << 8) | this.buffer[i++];
					readChunk(len);
				} else if (opcode == 78) { //OP_PUSHDATA4
					len = (this.buffer[i++] << 24) | (this.buffer[i++] << 16) | (this.buffer[i++] << 8) | this.buffer[i++];
					readChunk(len);
				} else {
					this.chunks.push(opcode);
				}

				if(i<0x00){
					break;
				}
			}

			return true;
		};

		/* decode the redeemscript of a multisignature transaction */
		r.decodeRedeemScript = function(script){
			var r = false;
			try {
				var s = coinjs.script(Crypto.util.hexToBytes(script));
				if((s.chunks.length>=3) && s.chunks[s.chunks.length-1] == 174){//OP_CHECKMULTISIG
					r = {};
					r.signaturesRequired = s.chunks[0]-80;
					var pubkeys = [];
					for(var i=1;i<s.chunks.length-2;i++){
						pubkeys.push(Crypto.util.bytesToHex(s.chunks[i]));
					}
					r.pubkeys = pubkeys;
					var multi = coinjs.pubkeys2MultisigAddress(pubkeys, r.signaturesRequired);
					r.address = multi['address'];
					r.type = 'multisig__'; // using __ for now to differentiat from the other object .type == "multisig"
				} else if((s.chunks.length==2) && (s.buffer[0] == 0 && s.buffer[1] == 20)){ // SEGWIT
					r = {};
					r.type = "segwit__";
					var rs = Crypto.util.bytesToHex(s.buffer);
					r.address = coinjs.pubkey2address(rs, coinjs.multisig);
					r.redeemscript = rs;

				} else if(s.chunks.length == 5 && s.chunks[1] == 177 && s.chunks[2] == 117 && s.chunks[4] == 172){
					// ^ <unlocktime> OP_CHECKLOCKTIMEVERIFY OP_DROP <pubkey> OP_CHECKSIG ^
					r = {}
					r.pubkey = Crypto.util.bytesToHex(s.chunks[3]);
					r.checklocktimeverify = coinjs.bytesToNum(s.chunks[0].slice());
					r.address = coinjs.simpleHodlAddress(r.pubkey, r.checklocktimeverify).address;
					r.type = "hodl__";
				}
			} catch(e) {
				// console.log(e);
				r = false;
			}
			return r;
		}

		/* create output script to spend */
		r.spendToScript = function(address){
			var addr = coinjs.addressDecode(address);
			var s = coinjs.script();
			if(addr.version==coinjs.multisig){ // multisig address
				s.writeOp(169); //OP_HASH160
				s.writeBytes(addr.bytes);
				s.writeOp(135); //OP_EQUAL
			} else { // regular address
				s.writeOp(118); //OP_DUP
				s.writeOp(169); //OP_HASH160
				s.writeBytes(addr.bytes);
				s.writeOp(136); //OP_EQUALVERIFY
				s.writeOp(172); //OP_CHECKSIG
			}
			return s;
		}

		/* geneate a (script) pubkey hash of the address - used for when signing */
		r.pubkeyHash = function(address) {
			var addr = coinjs.addressDecode(address);
			var s = coinjs.script();
			s.writeOp(118);//OP_DUP
			s.writeOp(169);//OP_HASH160
			s.writeBytes(addr.bytes);
			s.writeOp(136);//OP_EQUALVERIFY
			s.writeOp(172);//OP_CHECKSIG
			return s;
		}

		/* write to buffer */
		r.writeOp = function(op){
			this.buffer.push(op);
			this.chunks.push(op);
			return true;
		}

		/* write bytes to buffer */
		r.writeBytes = function(data){
			if (data.length < 76) {	//OP_PUSHDATA1
				this.buffer.push(data.length);
			} else if (data.length <= 0xff) {
				this.buffer.push(76); //OP_PUSHDATA1
				this.buffer.push(data.length);
			} else if (data.length <= 0xffff) {
				this.buffer.push(77); //OP_PUSHDATA2
				this.buffer.push(data.length & 0xff);
				this.buffer.push((data.length >>> 8) & 0xff);
			} else {
				this.buffer.push(78); //OP_PUSHDATA4
				this.buffer.push(data.length & 0xff);
				this.buffer.push((data.length >>> 8) & 0xff);
				this.buffer.push((data.length >>> 16) & 0xff);
				this.buffer.push((data.length >>> 24) & 0xff);
			}
			this.buffer = this.buffer.concat(data);
			this.chunks.push(data);
			return true;
		}

		r.parse();
		return r;
	}

	/* start of transaction functions */

	/* create a new transaction object */
	coinjs.transaction = function() {

		var r = {};
		r.version = 1;
		r.lock_time = 0;
		r.ins = [];
		r.outs = [];
		r.witness = [];
		r.timestamp = null;
		r.block = null;

		/* add an input to a transaction */
		r.addinput = function(txid, index, script, sequence){
			var o = {};
			o.outpoint = {'hash':txid, 'index':index};
			o.script = coinjs.script(script||[]);
			o.sequence = sequence || ((r.lock_time==0) ? 4294967295 : 0);
			return this.ins.push(o);
		}

		/* add an output to a transaction */
		r.addoutput = function(address, value){
			var o = {};
			o.value = new BigInteger('' + Math.round((value*1) * 1e8), 10);
			var s = coinjs.script();
			o.script = s.spendToScript(address);

			return this.outs.push(o);
		}

		/* add two outputs for stealth addresses to a transaction */
		r.addstealth = function(stealth, value){
			var ephemeralKeyBigInt = BigInteger.fromByteArrayUnsigned(Crypto.util.hexToBytes(coinjs.newPrivkey()));
			var curve = EllipticCurve.getSECCurveByName("secp256k1");
			
			var p = EllipticCurve.fromHex("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2F");
			var a = BigInteger.ZERO;
			var b = EllipticCurve.fromHex("7");
			var calccurve = new EllipticCurve.CurveFp(p, a, b);
			
			var ephemeralPt = curve.getG().multiply(ephemeralKeyBigInt);
			var scanPt = calccurve.decodePointHex(stealth.scankey);
			var sharedPt = scanPt.multiply(ephemeralKeyBigInt);
			var stealthindexKeyBigInt = BigInteger.fromByteArrayUnsigned(Crypto.SHA256(sharedPt.getEncoded(true), {asBytes: true}));
			
			var stealthindexPt = curve.getG().multiply(stealthindexKeyBigInt);
			var spendPt = calccurve.decodePointHex(stealth.spendkey);
			var addressPt = spendPt.add(stealthindexPt);
			
			var sendaddress = coinjs.pubkey2address(Crypto.util.bytesToHex(addressPt.getEncoded(true)));
			
			
			var OPRETBytes = [6].concat(Crypto.util.randomBytes(4)).concat(ephemeralPt.getEncoded(true)); // ephemkey data
			var q = coinjs.script();
			q.writeOp(106); // OP_RETURN
			q.writeBytes(OPRETBytes);
			v = {};
			v.value = 0;
			v.script = q;
			
			this.outs.push(v);
			
			var o = {};
			o.value = new BigInteger('' + Math.round((value*1) * 1e8), 10);
			var s = coinjs.script();
			o.script = s.spendToScript(sendaddress);
			
			return this.outs.push(o);
		}

		/* add data to a transaction */
		r.adddata = function(data){
			var r = false;
			if(((data.match(/^[a-f0-9]+$/gi)) && data.length<160) && (data.length%2)==0) {
				var s = coinjs.script();
				s.writeOp(106); // OP_RETURN
				s.writeBytes(Crypto.util.hexToBytes(data));
				o = {};
				o.value = 0;
				o.script = s;
				return this.outs.push(o);
			}
			return r;
		}

		/* list unspent transactions */
		r.listUnspent = function(address, callback) {
			coinjs.ajax(coinjs.host+'?uid='+coinjs.uid+'&key='+coinjs.key+'&setmodule=addresses&request=unspent&address='+address+'&r='+Math.random(), callback, "GET");
		}

		/* add unspent to transaction */
		r.addUnspent = function(address, callback, script, segwit){
			var self = this;
			this.listUnspent(address, function(data){
				var s = coinjs.script();
				var pubkeyScript = s.pubkeyHash(address);
				var value = 0;
				var total = 0;
				var x = {};

				if (window.DOMParser) {
					parser=new DOMParser();
					xmlDoc=parser.parseFromString(data,"text/xml");
				} else {
					xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
					xmlDoc.async=false;
					xmlDoc.loadXML(data);
				}

				var unspent = xmlDoc.getElementsByTagName("unspent")[0];

				for(i=1;i<=unspent.childElementCount;i++){
					var u = xmlDoc.getElementsByTagName("unspent_"+i)[0]
					var txhash = (u.getElementsByTagName("tx_hash")[0].childNodes[0].nodeValue).match(/.{1,2}/g).reverse().join("")+'';
					var n = u.getElementsByTagName("tx_output_n")[0].childNodes[0].nodeValue;
					var scr = script || u.getElementsByTagName("script")[0].childNodes[0].nodeValue;

					if(segwit){
						/* this is a small hack to include the value with the redeemscript to make the signing procedure smoother. 
						It is not standard and removed during the signing procedure. */

						s = coinjs.script();
						s.writeBytes(Crypto.util.hexToBytes(script));
						s.writeOp(0);
						s.writeBytes(coinjs.numToBytes(u.getElementsByTagName("value")[0].childNodes[0].nodeValue*1, 8));
						scr = Crypto.util.bytesToHex(s.buffer);
					}

					self.addinput(txhash, n, scr);
					value += u.getElementsByTagName("value")[0].childNodes[0].nodeValue*1;
					total++;
				}

				x.unspent = $(xmlDoc).find("unspent");
				x.value = value;
				x.total = total;
				return callback(x);
			});
		}

		/* add unspent and sign */
		r.addUnspentAndSign = function(wif, callback){
			var self = this;
			var address = coinjs.wif2address(wif);
			self.addUnspent(address['address'], function(data){
				self.sign(wif);
				return callback(data);
			});
		}

		/* broadcast a transaction */
		r.broadcast = function(callback, txhex){
			var tx = txhex || this.serialize();
			coinjs.ajax(coinjs.host+'?uid='+coinjs.uid+'&key='+coinjs.key+'&setmodule=bitcoin&request=sendrawtransaction&rawtx='+tx+'&r='+Math.random(), callback, "GET");
		}

		/* generate the transaction hash to sign from a transaction input */
		r.transactionHash = function(index, sigHashType) {

			var clone = coinjs.clone(this);
			var shType = sigHashType || 1;

			/* black out all other ins, except this one */
			for (var i = 0; i < clone.ins.length; i++) {
				if(index!=i){
					clone.ins[i].script = coinjs.script();
				}
			}

			var extract = this.extractScriptKey(index);
			clone.ins[index].script = coinjs.script(extract['script']);

			if((clone.ins) && clone.ins[index]){

				/* SIGHASH : For more info on sig hashs see https://en.bitcoin.it/wiki/OP_CHECKSIG
					and https://bitcoin.org/en/developer-guide#signature-hash-type */

				if(shType == 1){
					//SIGHASH_ALL 0x01

				} else if(shType == 2){
					//SIGHASH_NONE 0x02
					clone.outs = [];
					for (var i = 0; i < clone.ins.length; i++) {
						if(index!=i){
							clone.ins[i].sequence = 0;
						}
					}

				} else if(shType == 3){

					//SIGHASH_SINGLE 0x03
					clone.outs.length = index + 1;

					for(var i = 0; i < index; i++){
						clone.outs[i].value = -1;
						clone.outs[i].script.buffer = [];
					}

					for (var i = 0; i < clone.ins.length; i++) {
						if(index!=i){
							clone.ins[i].sequence = 0;
						}
					}

				} else if (shType >= 128){
					//SIGHASH_ANYONECANPAY 0x80
					clone.ins = [clone.ins[index]];

					if(shType==129){
						// SIGHASH_ALL + SIGHASH_ANYONECANPAY

					} else if(shType==130){
						// SIGHASH_NONE + SIGHASH_ANYONECANPAY
						clone.outs = [];

					} else if(shType==131){
                                                // SIGHASH_SINGLE + SIGHASH_ANYONECANPAY
						clone.outs.length = index + 1;
						for(var i = 0; i < index; i++){
							clone.outs[i].value = -1;
							clone.outs[i].script.buffer = [];
						}
					}
				}

				var buffer = Crypto.util.hexToBytes(clone.serialize());
				buffer = buffer.concat(coinjs.numToBytes(parseInt(shType), 4));
				var hash = Crypto.SHA256(buffer, {asBytes: true});
				var r = Crypto.util.bytesToHex(Crypto.SHA256(hash, {asBytes: true}));
				return r;
			} else {
				return false;
			}
		}

		/* generate a segwit transaction hash to sign from a transaction input */
		r.transactionHashSegWitV0 = function(index, sigHashType){
			/* 
			   Notice: coinb.in by default, deals with segwit transactions in a non-standard way.
			   Segwit transactions require that input values are included in the transaction hash.
			   To save wasting resources and potentially slowing down this service, we include the amount with the 
			   redeem script to generate the transaction hash and remove it after its signed.
			*/

			// start redeem script check
			var extract = this.extractScriptKey(index);
			if(extract['type'] != 'segwit'){
				return {'result':0, 'fail':'redeemscript', 'response':'redeemscript missing or not valid for segwit'};
			}

			var scriptcode = Crypto.util.hexToBytes(extract['script']);
			if(scriptcode[0] != 0){
				return {'result':0, 'fail':'scriptcode', 'response':'redeemscript is not valid'};
			}

			if(extract['value'] == -1){
				return {'result':0, 'fail':'value', 'response':'unable to generate a valid segwit hash without a value'};				
			}

			// end of redeem script check

			scriptcode = scriptcode.slice(1);
			scriptcode.unshift(25, 118, 169);
			scriptcode.push(136, 172);

			var value = coinjs.numToBytes(extract['value'], 8);

			// start

			var zero = coinjs.numToBytes(0, 32);
			var version = coinjs.numToBytes(parseInt(this.version), 4);

			var bufferTmp = [];
			if(!(sigHashType >= 80)){	// not sighash anyonecanpay 
				for(var i = 0; i < this.ins.length; i++){
					bufferTmp = bufferTmp.concat(Crypto.util.hexToBytes(this.ins[i].outpoint.hash).reverse());
					bufferTmp = bufferTmp.concat(coinjs.numToBytes(this.ins[i].outpoint.index, 4));
				}
			}
			var hashPrevouts = bufferTmp.length >= 1 ? Crypto.SHA256(Crypto.SHA256(bufferTmp, {asBytes: true}), {asBytes: true}) : zero; 

			var bufferTmp = [];
			if(!(sigHashType >= 80) && sigHashType != 2 && sigHashType != 3){ // not sighash anyonecanpay & single & none
				for(var i = 0; i < this.ins.length; i++){
					bufferTmp = bufferTmp.concat(coinjs.numToBytes(this.ins[i].sequence, 4));
				}
			}
			var hashSequence = bufferTmp.length >= 1 ? Crypto.SHA256(Crypto.SHA256(bufferTmp, {asBytes: true}), {asBytes: true}) : zero; 

			var outpoint = Crypto.util.hexToBytes(this.ins[index].outpoint.hash).reverse();
			outpoint = outpoint.concat(coinjs.numToBytes(this.ins[index].outpoint.index, 4));

			var nsequence = coinjs.numToBytes(this.ins[index].sequence, 4);
			var hashOutputs = zero;
			var bufferTmp = [];
			if(sigHashType != 2 && sigHashType != 3){		// not sighash single & none
				for(var i = 0; i < this.outs.length; i++ ){
					bufferTmp = bufferTmp.concat(coinjs.numToBytes(this.outs[i].value, 8));
					bufferTmp = bufferTmp.concat(coinjs.numToVarInt(this.outs[i].script.buffer.length));
					bufferTmp = bufferTmp.concat(this.outs[i].script.buffer);
				}
				hashOutputs = Crypto.SHA256(Crypto.SHA256(bufferTmp, {asBytes: true}), {asBytes: true});

			} else if ((sigHashType == 2) && index < this.outs.length){ // is sighash single
				bufferTmp = bufferTmp.concat(coinjs.numToBytes(this.outs[index].value, 8));
				bufferTmp = bufferTmp.concat(coinjs.numToVarInt(this.outs[i].script.buffer.length));
				bufferTmp = bufferTmp.concat(this.outs[index].script.buffer);
				hashOutputs = Crypto.SHA256(Crypto.SHA256(bufferTmp, {asBytes: true}), {asBytes: true});
			}

			var locktime = coinjs.numToBytes(this.lock_time, 4);
			var sighash = coinjs.numToBytes(sigHashType, 4);

			var buffer = []; 
			buffer = buffer.concat(version);
			buffer = buffer.concat(hashPrevouts);
			buffer = buffer.concat(hashSequence);
			buffer = buffer.concat(outpoint);
			buffer = buffer.concat(scriptcode);
			buffer = buffer.concat(value);
			buffer = buffer.concat(nsequence);
			buffer = buffer.concat(hashOutputs);
			buffer = buffer.concat(locktime);
			buffer = buffer.concat(sighash);

			var hash = Crypto.SHA256(buffer, {asBytes: true});
			return {'result':1,'hash':Crypto.util.bytesToHex(Crypto.SHA256(hash, {asBytes: true})), 'response':'hash generated'};
		}

		/* extract the scriptSig, used in the transactionHash() function */
		r.extractScriptKey = function(index) {
			if(this.ins[index]){
				if((this.ins[index].script.chunks.length==5) && this.ins[index].script.chunks[4]==172 && coinjs.isArray(this.ins[index].script.chunks[2])){ //OP_CHECKSIG
					// regular scriptPubkey (not signed)
					return {'type':'scriptpubkey', 'signed':'false', 'signatures':0, 'script': Crypto.util.bytesToHex(this.ins[index].script.buffer)};
				} else if((this.ins[index].script.chunks.length==2) && this.ins[index].script.chunks[0][0]==48 && this.ins[index].script.chunks[1].length == 5 && this.ins[index].script.chunks[1][1]==177){//OP_CHECKLOCKTIMEVERIFY
					// hodl script (signed)
					return {'type':'hodl', 'signed':'true', 'signatures':1, 'script': Crypto.util.bytesToHex(this.ins[index].script.buffer)};
				} else if((this.ins[index].script.chunks.length==2) && this.ins[index].script.chunks[0][0]==48){ 
					// regular scriptPubkey (probably signed)
					return {'type':'scriptpubkey', 'signed':'true', 'signatures':1, 'script': Crypto.util.bytesToHex(this.ins[index].script.buffer)};
				} else if(this.ins[index].script.chunks.length == 5 && this.ins[index].script.chunks[1] == 177){//OP_CHECKLOCKTIMEVERIFY
					// hodl script (not signed)
					return {'type':'hodl', 'signed':'false', 'signatures': 0, 'script': Crypto.util.bytesToHex(this.ins[index].script.buffer)};
				} else if((this.ins[index].script.chunks.length <= 3 && this.ins[index].script.chunks.length > 0) && this.ins[index].script.chunks[0].length == 22 && this.ins[index].script.chunks[0][0] == 0){
					// segwit script
					var signed = ((this.witness[index]) && this.witness[index].length==2) ? 'true' : 'false';
					var sigs = (signed == 'true') ? 1 : 0;
					var value = -1; // no value found
					if((this.ins[index].script.chunks[2]) && this.ins[index].script.chunks[2].length==8){
						value = coinjs.bytesToNum(this.ins[index].script.chunks[2]);  // value found encoded in transaction (THIS IS NON STANDARD)
					}
					return {'type':'segwit', 'signed':signed, 'signatures': sigs, 'script': Crypto.util.bytesToHex(this.ins[index].script.chunks[0]), 'value': value};
				} else if (this.ins[index].script.chunks[0]==0 && this.ins[index].script.chunks[this.ins[index].script.chunks.length-1][this.ins[index].script.chunks[this.ins[index].script.chunks.length-1].length-1]==174) { // OP_CHECKMULTISIG
					// multisig script, with signature(s) included
					return {'type':'multisig', 'signed':'true', 'signatures':this.ins[index].script.chunks.length-2, 'script': Crypto.util.bytesToHex(this.ins[index].script.chunks[this.ins[index].script.chunks.length-1])};
				} else if (this.ins[index].script.chunks[0]>=80 && this.ins[index].script.chunks[this.ins[index].script.chunks.length-1]==174) { // OP_CHECKMULTISIG
					// multisig script, without signature!
					return {'type':'multisig', 'signed':'false', 'signatures':0, 'script': Crypto.util.bytesToHex(this.ins[index].script.buffer)};
				} else if (this.ins[index].script.chunks.length==0) {
					// empty
					return {'type':'empty', 'signed':'false', 'signatures':0, 'script': ''};
				} else {
					// something else
					return {'type':'unknown', 'signed':'false', 'signatures':0, 'script':Crypto.util.bytesToHex(this.ins[index].script.buffer)};
				}
			} else {
				return false;
			}
		}

		/* generate a signature from a transaction hash */
		r.transactionSig = function(index, wif, sigHashType, txhash){

			function serializeSig(r, s) {
				var rBa = r.toByteArraySigned();
				var sBa = s.toByteArraySigned();

				var sequence = [];
				sequence.push(0x02); // INTEGER
				sequence.push(rBa.length);
				sequence = sequence.concat(rBa);

				sequence.push(0x02); // INTEGER
				sequence.push(sBa.length);
				sequence = sequence.concat(sBa);

				sequence.unshift(sequence.length);
				sequence.unshift(0x30); // SEQUENCE

				return sequence;
			}

			var shType = sigHashType || 1;
			var hash = txhash || Crypto.util.hexToBytes(this.transactionHash(index, shType));

			if(hash){
				var curve = EllipticCurve.getSECCurveByName("secp256k1");
				var key = coinjs.wif2privkey(wif);
				var priv = BigInteger.fromByteArrayUnsigned(Crypto.util.hexToBytes(key['privkey']));
				var n = curve.getN();
				var e = BigInteger.fromByteArrayUnsigned(hash);
				var badrs = 0
				do {
					var k = this.deterministicK(wif, hash, badrs);
					var G = curve.getG();
					var Q = G.multiply(k);
					var r = Q.getX().toBigInteger().mod(n);
					var s = k.modInverse(n).multiply(e.add(priv.multiply(r))).mod(n);
					badrs++
				} while (r.compareTo(BigInteger.ZERO) <= 0 || s.compareTo(BigInteger.ZERO) <= 0);

				// Force lower s values per BIP62
				var halfn = n.shiftRight(1);
				if (s.compareTo(halfn) > 0) {
					s = n.subtract(s);
				};

				var sig = serializeSig(r, s);
				sig.push(parseInt(shType, 10));

				return Crypto.util.bytesToHex(sig);
			} else {
				return false;
			}
		}

		// https://tools.ietf.org/html/rfc6979#section-3.2
		r.deterministicK = function(wif, hash, badrs) {
			// if r or s were invalid when this function was used in signing,
			// we do not want to actually compute r, s here for efficiency, so,
			// we can increment badrs. explained at end of RFC 6979 section 3.2

			// wif is b58check encoded wif privkey.
			// hash is byte array of transaction digest.
			// badrs is used only if the k resulted in bad r or s.

			// some necessary things out of the way for clarity.
			badrs = badrs || 0;
			var key = coinjs.wif2privkey(wif);
			var x = Crypto.util.hexToBytes(key['privkey'])
			var curve = EllipticCurve.getSECCurveByName("secp256k1");
			var N = curve.getN();

			// Step: a
			// hash is a byteArray of the message digest. so h1 == hash in our case

			// Step: b
			var v = [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1];

			// Step: c
			var k = [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

			// Step: d
			k = Crypto.HMAC(Crypto.SHA256, v.concat([0]).concat(x).concat(hash), k, { asBytes: true });

			// Step: e
			v = Crypto.HMAC(Crypto.SHA256, v, k, { asBytes: true });

			// Step: f
			k = Crypto.HMAC(Crypto.SHA256, v.concat([1]).concat(x).concat(hash), k, { asBytes: true });

			// Step: g
			v = Crypto.HMAC(Crypto.SHA256, v, k, { asBytes: true });

			// Step: h1
			var T = [];

			// Step: h2 (since we know tlen = qlen, just copy v to T.)
			v = Crypto.HMAC(Crypto.SHA256, v, k, { asBytes: true });
			T = v;

			// Step: h3
			var KBigInt = BigInteger.fromByteArrayUnsigned(T);

			// loop if KBigInt is not in the range of [1, N-1] or if badrs needs incrementing.
			var i = 0
			while (KBigInt.compareTo(N) >= 0 || KBigInt.compareTo(BigInteger.ZERO) <= 0 || i < badrs) {
				k = Crypto.HMAC(Crypto.SHA256, v.concat([0]), k, { asBytes: true });
				v = Crypto.HMAC(Crypto.SHA256, v, k, { asBytes: true });
				v = Crypto.HMAC(Crypto.SHA256, v, k, { asBytes: true });
				T = v;
				KBigInt = BigInteger.fromByteArrayUnsigned(T);
				i++
			};

			return KBigInt;
		};

		/* sign a "standard" input */
		r.signinput = function(index, wif, sigHashType){
			var key = coinjs.wif2pubkey(wif);
			var shType = sigHashType || 1;
			var signature = this.transactionSig(index, wif, shType);
			var s = coinjs.script();
			s.writeBytes(Crypto.util.hexToBytes(signature));
			s.writeBytes(Crypto.util.hexToBytes(key['pubkey']));
			this.ins[index].script = s;
			return true;
		}

		/* signs a time locked / hodl input */
		r.signhodl = function(index, wif, sigHashType){
			var shType = sigHashType || 1;
			var signature = this.transactionSig(index, wif, shType);
			var redeemScript = this.ins[index].script.buffer
			var s = coinjs.script();
			s.writeBytes(Crypto.util.hexToBytes(signature));
			s.writeBytes(redeemScript);
			this.ins[index].script = s;
			return true;
		}
		
		/* sign a multisig input */
		r.signmultisig = function(index, wif, sigHashType){

			function scriptListPubkey(redeemScript){
				var r = {};
				for(var i=1;i<redeemScript.chunks.length-2;i++){
					r[i] = Crypto.util.hexToBytes(coinjs.pubkeydecompress(Crypto.util.bytesToHex(redeemScript.chunks[i])));
				}
				return r;
			}
	
			function scriptListSigs(scriptSig){
				var r = {};
				var c = 0;
				if (scriptSig.chunks[0]==0 && scriptSig.chunks[scriptSig.chunks.length-1][scriptSig.chunks[scriptSig.chunks.length-1].length-1]==174){
					for(var i=1;i<scriptSig.chunks.length-1;i++){				
						if (scriptSig.chunks[i] != 0){
							c++;
							r[c] = scriptSig.chunks[i];
						}
					}
				}
				return r;
			}

			var redeemScript = (this.ins[index].script.chunks[this.ins[index].script.chunks.length-1]==174) ? this.ins[index].script.buffer : this.ins[index].script.chunks[this.ins[index].script.chunks.length-1];

			var pubkeyList = scriptListPubkey(coinjs.script(redeemScript));
			var sigsList = scriptListSigs(this.ins[index].script);

			var shType = sigHashType || 1;
			var sighash = Crypto.util.hexToBytes(this.transactionHash(index, shType));
			var signature = Crypto.util.hexToBytes(this.transactionSig(index, wif, shType));

			sigsList[coinjs.countObject(sigsList)+1] = signature;

			var s = coinjs.script();

			s.writeOp(0);

			for(x in pubkeyList){
				for(y in sigsList){
					this.ins[index].script.buffer = redeemScript;
					sighash = Crypto.util.hexToBytes(this.transactionHash(index, sigsList[y].slice(-1)[0]*1));
					if(coinjs.verifySignature(sighash, sigsList[y], pubkeyList[x])){
						s.writeBytes(sigsList[y]);
					}
				}
			}

			s.writeBytes(redeemScript);
			this.ins[index].script = s;
			return true;
		}

		/* sign segwit input */
		r.signsegwit = function(index, wif, sigHashType){
			var shType = sigHashType || 1;

			var wif2 = coinjs.wif2pubkey(wif);
			var segwit = coinjs.segwitAddress(wif2['pubkey']);

			if(segwit['redeemscript'] == Crypto.util.bytesToHex(this.ins[index].script.chunks[0])){
				var txhash = this.transactionHashSegWitV0(index, shType);
				if(txhash.result == 1){
					var segwitHash = Crypto.util.hexToBytes(txhash.hash);
					var signature = this.transactionSig(index, wif, shType, segwitHash);
				
					// remove any non standard data we store, i.e. input value
					var script = coinjs.script();
					script.writeBytes(this.ins[index].script.chunks[0]);	
					this.ins[index].script = script;

					this.witness.push([signature, wif2['pubkey']]);

					/* reorder witness data */
					var witness_order = [];
					for(var i = 0; i < this.ins.length; i++){
						for(var y = 0; y < this.witness.length; y++){
							var sw = coinjs.segwitAddress(this.witness[y][1]);
							if(sw['redeemscript'] == Crypto.util.bytesToHex(this.ins[i].script.chunks[0])){
								witness_order.push(this.witness[y]);
							}
						}
					}
					this.witness = witness_order;
				}
			}
			return true;
		}

		/* sign inputs */
		r.sign = function(wif, sigHashType){
			var shType = sigHashType || 1;
			for (var i = 0; i < this.ins.length; i++) {
				var d = this.extractScriptKey(i);

				var w2a = coinjs.wif2address(wif);
				var script = coinjs.script();
				var pubkeyHash = script.pubkeyHash(w2a['address']);

				if(((d['type'] == 'scriptpubkey' && d['script']==Crypto.util.bytesToHex(pubkeyHash.buffer)) || d['type'] == 'empty') && d['signed'] == "false"){
					this.signinput(i, wif, shType);

				} else if (d['type'] == 'hodl' && d['signed'] == "false") {
					this.signhodl(i, wif, shType);

				} else if (d['type'] == 'multisig') {
					this.signmultisig(i, wif, shType);

				} else if (d['type'] == 'segwit') {
					this.signsegwit(i, wif, shType);

				} else {
					// could not sign
				}
			}
			return this.serialize();
		}

		/* serialize a transaction */
		r.serialize = function(){
			var buffer = [];
			buffer = buffer.concat(coinjs.numToBytes(parseInt(this.version),4));

			if(this.witness.length>=1){
				buffer = buffer.concat([0x00, 0x01]);
			}

			buffer = buffer.concat(coinjs.numToVarInt(this.ins.length));
			for (var i = 0; i < this.ins.length; i++) {
				var txin = this.ins[i];
				buffer = buffer.concat(Crypto.util.hexToBytes(txin.outpoint.hash).reverse());
				buffer = buffer.concat(coinjs.numToBytes(parseInt(txin.outpoint.index),4));
				var scriptBytes = txin.script.buffer;
				buffer = buffer.concat(coinjs.numToVarInt(scriptBytes.length));
				buffer = buffer.concat(scriptBytes);
				buffer = buffer.concat(coinjs.numToBytes(parseInt(txin.sequence),4));
			}
			buffer = buffer.concat(coinjs.numToVarInt(this.outs.length));

			for (var i = 0; i < this.outs.length; i++) {
				var txout = this.outs[i];
 				buffer = buffer.concat(coinjs.numToBytes(txout.value,8));
				var scriptBytes = txout.script.buffer;
				buffer = buffer.concat(coinjs.numToVarInt(scriptBytes.length));
				buffer = buffer.concat(scriptBytes);
			}

			if(this.witness.length>=1){
				for(var i = 0; i < this.witness.length; i++){
	 				buffer = buffer.concat(coinjs.numToVarInt(this.witness[i].length));
					for(var x = 0; x < this.witness[i].length; x++){
		 				buffer = buffer.concat(coinjs.numToVarInt(Crypto.util.hexToBytes(this.witness[i][x]).length));
						buffer = buffer.concat(Crypto.util.hexToBytes(this.witness[i][x]));
					}
				}
			}

			buffer = buffer.concat(coinjs.numToBytes(parseInt(this.lock_time),4));
			return Crypto.util.bytesToHex(buffer);
		}

		/* deserialize a transaction */
		r.deserialize = function(buffer){
			if (typeof buffer == "string") {
				buffer = Crypto.util.hexToBytes(buffer)
			}

			var pos = 0;
			var witness = false;

			var readAsInt = function(bytes) {
				if (bytes == 0) return 0;
				pos++;
				return buffer[pos-1] + readAsInt(bytes-1) * 256;
			}

			var readVarInt = function() {
				pos++;
				if (buffer[pos-1] < 253) {
					return buffer[pos-1];
				}
				return readAsInt(buffer[pos-1] - 251);
			}

			var readBytes = function(bytes) {
				pos += bytes;
				return buffer.slice(pos - bytes, pos);
			}

			var readVarString = function() {
				var size = readVarInt();
				return readBytes(size);
			}

			var obj = new coinjs.transaction();
			obj.version = readAsInt(4);

			if(buffer[pos] == 0x00 && buffer[pos+1] == 0x01){
				// segwit transaction
				witness = true;
				obj.witness = [];
				pos += 2;
			}

			var ins = readVarInt();
			for (var i = 0; i < ins; i++) {
				obj.ins.push({
					outpoint: {
						hash: Crypto.util.bytesToHex(readBytes(32).reverse()),
 						index: readAsInt(4)
					},
					script: coinjs.script(readVarString()),
					sequence: readAsInt(4)
				});
			}

			var outs = readVarInt();
			for (var i = 0; i < outs; i++) {
				obj.outs.push({
					value: coinjs.bytesToNum(readBytes(8)),
					script: coinjs.script(readVarString())
				});
			}

			if(witness == true){
				for (i = 0; i < ins; ++i) {
					var count = readVarInt();
					var vector = [];
					for(var y = 0; y < count; y++){
						var slice = readVarInt();
						pos += slice;
						if(!coinjs.isArray(obj.witness[i])){
							obj.witness[i] = [];
						}
						obj.witness[i].push(Crypto.util.bytesToHex(buffer.slice(pos - slice, pos)));
					}
				}
			}

 			obj.lock_time = readAsInt(4);
			return obj;
		}

		r.size = function(){
			return ((this.serialize()).length/2).toFixed(0);
		}

		return r;
	}

	/* start of signature vertification functions */

	coinjs.verifySignature = function (hash, sig, pubkey) {

		function parseSig (sig) {
			var cursor;
			if (sig[0] != 0x30)
				throw new Error("Signature not a valid DERSequence");

			cursor = 2;
			if (sig[cursor] != 0x02)
				throw new Error("First element in signature must be a DERInteger"); ;

			var rBa = sig.slice(cursor + 2, cursor + 2 + sig[cursor + 1]);

			cursor += 2 + sig[cursor + 1];
			if (sig[cursor] != 0x02)
				throw new Error("Second element in signature must be a DERInteger");

			var sBa = sig.slice(cursor + 2, cursor + 2 + sig[cursor + 1]);

			cursor += 2 + sig[cursor + 1];

			var r = BigInteger.fromByteArrayUnsigned(rBa);
			var s = BigInteger.fromByteArrayUnsigned(sBa);

			return { r: r, s: s };
		}

		var r, s;

		if (coinjs.isArray(sig)) {
			var obj = parseSig(sig);
			r = obj.r;
			s = obj.s;
		} else if ("object" === typeof sig && sig.r && sig.s) {
			r = sig.r;
			s = sig.s;
		} else {
			throw "Invalid value for signature";
		}

		var Q;
		if (coinjs.isArray(pubkey)) {
			var ecparams = EllipticCurve.getSECCurveByName("secp256k1");
			Q = EllipticCurve.PointFp.decodeFrom(ecparams.getCurve(), pubkey);
		} else {
			throw "Invalid format for pubkey value, must be byte array";
		}
		var e = BigInteger.fromByteArrayUnsigned(hash);

		return coinjs.verifySignatureRaw(e, r, s, Q);
	}

	coinjs.verifySignatureRaw = function (e, r, s, Q) {
		var ecparams = EllipticCurve.getSECCurveByName("secp256k1");
		var n = ecparams.getN();
		var G = ecparams.getG();

		if (r.compareTo(BigInteger.ONE) < 0 || r.compareTo(n) >= 0)
			return false;

		if (s.compareTo(BigInteger.ONE) < 0 || s.compareTo(n) >= 0)
			return false;

		var c = s.modInverse(n);

		var u1 = e.multiply(c).mod(n);
		var u2 = r.multiply(c).mod(n);

		var point = G.multiply(u1).add(Q.multiply(u2));

		var v = point.getX().toBigInteger().mod(n);

		return v.equals(r);
	}

	/* start of privates functions */

	/* base58 encode function */
	coinjs.base58encode = function(buffer) {
		var alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
		var base = BigInteger.valueOf(58);

		var bi = BigInteger.fromByteArrayUnsigned(buffer);
		var chars = [];

		while (bi.compareTo(base) >= 0) {
			var mod = bi.mod(base);
			chars.unshift(alphabet[mod.intValue()]);
			bi = bi.subtract(mod).divide(base);
		}

		chars.unshift(alphabet[bi.intValue()]);
		for (var i = 0; i < buffer.length; i++) {
			if (buffer[i] == 0x00) {
				chars.unshift(alphabet[0]);
			} else break;
		}
		return chars.join('');
	}

	/* base58 decode function */
	coinjs.base58decode = function(buffer){
		var alphabet = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
		var base = BigInteger.valueOf(58);
		var validRegex = /^[1-9A-HJ-NP-Za-km-z]+$/;

		var bi = BigInteger.valueOf(0);
		var leadingZerosNum = 0;
		for (var i = buffer.length - 1; i >= 0; i--) {
			var alphaIndex = alphabet.indexOf(buffer[i]);
			if (alphaIndex < 0) {
				throw "Invalid character";
			}
			bi = bi.add(BigInteger.valueOf(alphaIndex).multiply(base.pow(buffer.length - 1 - i)));

			if (buffer[i] == "1") leadingZerosNum++;
			else leadingZerosNum = 0;
		}

		var bytes = bi.toByteArrayUnsigned();
		while (leadingZerosNum-- > 0) bytes.unshift(0);
		return bytes;		
	}

	/* raw ajax function to avoid needing bigger frame works like jquery, mootools etc */
	coinjs.ajax = function(u, f, m, a){
		var x = false;
		try{
			x = new ActiveXObject('Msxml2.XMLHTTP')
		} catch(e) {
			try {
				x = new ActiveXObject('Microsoft.XMLHTTP')
			} catch(e) {
				x = new XMLHttpRequest()
			}
		}

		if(x==false) {
			return false;
		}

		x.open(m, u, true);
		x.onreadystatechange=function(){
			if((x.readyState==4) && f)
				f(x.responseText);
		};

		if(m == 'POST'){
			x.setRequestHeader('Content-type','application/x-www-form-urlencoded');
		}

		x.send(a);
	}

	/* clone an object */
	coinjs.clone = function(obj) {
		if(obj == null || typeof(obj) != 'object') return obj;
		var temp = new obj.constructor();

		for(var key in obj) {
			if(obj.hasOwnProperty(key)) {
				temp[key] = coinjs.clone(obj[key]);
			}
		}
 		return temp;
	}

	coinjs.numToBytes = function(num,bytes) {
		if (typeof bytes === "undefined") bytes = 8;
		if (bytes == 0) { 
			return [];
		} else if (num == -1){
			return Crypto.util.hexToBytes("ffffffffffffffff");
		} else {
			return [num % 256].concat(coinjs.numToBytes(Math.floor(num / 256),bytes-1));
		}
	}

	coinjs.numToByteArray = function(num) {
		if (num <= 256) { 
			return [num];
		} else {
			return [num % 256].concat(coinjs.numToByteArray(Math.floor(num / 256)));
		}
	}

	coinjs.numToVarInt = function(num) {
		if (num < 253) {
			return [num];
		} else if (num < 65536) {
			return [253].concat(coinjs.numToBytes(num,2));
		} else if (num < 4294967296) {
			return [254].concat(coinjs.numToBytes(num,4));
		} else {
			return [255].concat(coinjs.numToBytes(num,8));
		}
	}

	coinjs.bytesToNum = function(bytes) {
		if (bytes.length == 0) return 0;
		else return bytes[0] + 256 * coinjs.bytesToNum(bytes.slice(1));
	}

	coinjs.uint = function(f, size) {
		if (f.length < size)
			throw new Error("not enough data");
		var n = 0;
		for (var i = 0; i < size; i++) {
			n *= 256;
			n += f[i];
		}
		return n;
	}

	coinjs.isArray = function(o){
		return Object.prototype.toString.call(o) === '[object Array]';
	}

	coinjs.countObject = function(obj){
		var count = 0;
		var i;
		for (i in obj) {
			if (obj.hasOwnProperty(i)) {
				count++;
			}
		}
		return count;
	}

	coinjs.random = function(length) {
		var r = "";
		var l = length || 25;
		var chars = "!$%^&*()_+{}:@~?><|\./;'#][=-abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
		for(x=0;x<l;x++) {
			r += chars.charAt(Math.floor(Math.random() * 62));
		}
		return r;
	}

})();