mymonero-core-js/cryptonote_utils/cryptonote_utils.js

// Copyright (c) 2014-2018, MyMonero.com
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without modification, are
// permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice, this list of
//	conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright notice, this list
//	of conditions and the following disclaimer in the documentation and/or other
//	materials provided with the distribution.
//
// 3. Neither the name of the copyright holder nor the names of its contributors may be
//	used to endorse or promote products derived from this software without specific
//	prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

// Original Author: Lucas Jones
// Modified to remove jQuery dep and support modular inclusion of deps by Paul Shapiro (2016)
// Modified to add RingCT support by luigi1111 (2017)
//
// v--- These should maybe be injected into a context and supplied to currencyConfig for future platforms
const JSBigInt = require("./biginteger").BigInteger;
const cnBase58 = require("./cryptonote_base58").cnBase58;
const CNCrypto = require("./cryptonote_crypto_EMSCRIPTEN");
const mnemonic = require("./mnemonic");
const nacl = require("./nacl-fast-cn");
const sha3 = require("./sha3");
const nettype_utils = require("./nettype");

var cnUtil = function(currencyConfig) {
	var config = {}; // shallow copy of initConfig
	for (var key in currencyConfig) {
		config[key] = currencyConfig[key];
	}

	config.coinUnits = new JSBigInt(10).pow(config.coinUnitPlaces);

	var HASH_STATE_BYTES = 200;
	var HASH_SIZE = 32;
	var ADDRESS_CHECKSUM_SIZE = 4;
	var INTEGRATED_ID_SIZE = 8;
	var ENCRYPTED_PAYMENT_ID_TAIL = 141;
	//
	var UINT64_MAX = new JSBigInt(2).pow(64);
	var CURRENT_TX_VERSION = 2;
	var OLD_TX_VERSION = 1;
	var RCTTypeFull = 1;
	var RCTTypeSimple = 2;
	var TX_EXTRA_NONCE_MAX_COUNT = 255;
	var TX_EXTRA_TAGS = {
		PADDING: "00",
		PUBKEY: "01",
		NONCE: "02",
		MERGE_MINING: "03",
	};
	var TX_EXTRA_NONCE_TAGS = {
		PAYMENT_ID: "00",
		ENCRYPTED_PAYMENT_ID: "01",
	};
	var KEY_SIZE = 32;
	var STRUCT_SIZES = {
		GE_P3: 160,
		GE_P2: 120,
		GE_P1P1: 160,
		GE_CACHED: 160,
		EC_SCALAR: 32,
		EC_POINT: 32,
		KEY_IMAGE: 32,
		GE_DSMP: 160 * 8, // ge_cached * 8
		SIGNATURE: 64, // ec_scalar * 2
	};

	//RCT vars
	var H = "8b655970153799af2aeadc9ff1add0ea6c7251d54154cfa92c173a0dd39c1f94"; //base H for amounts
	var l = JSBigInt(
		"7237005577332262213973186563042994240857116359379907606001950938285454250989",
	); //curve order (not RCT specific)
	var I = "0100000000000000000000000000000000000000000000000000000000000000"; //identity element
	var Z = "0000000000000000000000000000000000000000000000000000000000000000"; //zero scalar
	//H2 object to speed up some operations
	var H2 = [
		"8b655970153799af2aeadc9ff1add0ea6c7251d54154cfa92c173a0dd39c1f94",
		"8faa448ae4b3e2bb3d4d130909f55fcd79711c1c83cdbccadd42cbe1515e8712",
		"12a7d62c7791654a57f3e67694ed50b49a7d9e3fc1e4c7a0bde29d187e9cc71d",
		"789ab9934b49c4f9e6785c6d57a498b3ead443f04f13df110c5427b4f214c739",
		"771e9299d94f02ac72e38e44de568ac1dcb2edc6edb61f83ca418e1077ce3de8",
		"73b96db43039819bdaf5680e5c32d741488884d18d93866d4074a849182a8a64",
		"8d458e1c2f68ebebccd2fd5d379f5e58f8134df3e0e88cad3d46701063a8d412",
		"09551edbe494418e81284455d64b35ee8ac093068a5f161fa6637559177ef404",
		"d05a8866f4df8cee1e268b1d23a4c58c92e760309786cdac0feda1d247a9c9a7",
		"55cdaad518bd871dd1eb7bc7023e1dc0fdf3339864f88fdd2de269fe9ee1832d",
		"e7697e951a98cfd5712b84bbe5f34ed733e9473fcb68eda66e3788df1958c306",
		"f92a970bae72782989bfc83adfaa92a4f49c7e95918b3bba3cdc7fe88acc8d47",
		"1f66c2d491d75af915c8db6a6d1cb0cd4f7ddcd5e63d3ba9b83c866c39ef3a2b",
		"3eec9884b43f58e93ef8deea260004efea2a46344fc5965b1a7dd5d18997efa7",
		"b29f8f0ccb96977fe777d489d6be9e7ebc19c409b5103568f277611d7ea84894",
		"56b1f51265b9559876d58d249d0c146d69a103636699874d3f90473550fe3f2c",
		"1d7a36575e22f5d139ff9cc510fa138505576b63815a94e4b012bfd457caaada",
		"d0ac507a864ecd0593fa67be7d23134392d00e4007e2534878d9b242e10d7620",
		"f6c6840b9cf145bb2dccf86e940be0fc098e32e31099d56f7fe087bd5deb5094",
		"28831a3340070eb1db87c12e05980d5f33e9ef90f83a4817c9f4a0a33227e197",
		"87632273d629ccb7e1ed1a768fa2ebd51760f32e1c0b867a5d368d5271055c6e",
		"5c7b29424347964d04275517c5ae14b6b5ea2798b573fc94e6e44a5321600cfb",
		"e6945042d78bc2c3bd6ec58c511a9fe859c0ad63fde494f5039e0e8232612bd5",
		"36d56907e2ec745db6e54f0b2e1b2300abcb422e712da588a40d3f1ebbbe02f6",
		"34db6ee4d0608e5f783650495a3b2f5273c5134e5284e4fdf96627bb16e31e6b",
		"8e7659fb45a3787d674ae86731faa2538ec0fdf442ab26e9c791fada089467e9",
		"3006cf198b24f31bb4c7e6346000abc701e827cfbb5df52dcfa42e9ca9ff0802",
		"f5fd403cb6e8be21472e377ffd805a8c6083ea4803b8485389cc3ebc215f002a",
		"3731b260eb3f9482e45f1c3f3b9dcf834b75e6eef8c40f461ea27e8b6ed9473d",
		"9f9dab09c3f5e42855c2de971b659328a2dbc454845f396ffc053f0bb192f8c3",
		"5e055d25f85fdb98f273e4afe08464c003b70f1ef0677bb5e25706400be620a5",
		"868bcf3679cb6b500b94418c0b8925f9865530303ae4e4b262591865666a4590",
		"b3db6bd3897afbd1df3f9644ab21c8050e1f0038a52f7ca95ac0c3de7558cb7a",
		"8119b3a059ff2cac483e69bcd41d6d27149447914288bbeaee3413e6dcc6d1eb",
		"10fc58f35fc7fe7ae875524bb5850003005b7f978c0c65e2a965464b6d00819c",
		"5acd94eb3c578379c1ea58a343ec4fcff962776fe35521e475a0e06d887b2db9",
		"33daf3a214d6e0d42d2300a7b44b39290db8989b427974cd865db011055a2901",
		"cfc6572f29afd164a494e64e6f1aeb820c3e7da355144e5124a391d06e9f95ea",
		"d5312a4b0ef615a331f6352c2ed21dac9e7c36398b939aec901c257f6cbc9e8e",
		"551d67fefc7b5b9f9fdbf6af57c96c8a74d7e45a002078a7b5ba45c6fde93e33",
		"d50ac7bd5ca593c656928f38428017fc7ba502854c43d8414950e96ecb405dc3",
		"0773e18ea1be44fe1a97e239573cfae3e4e95ef9aa9faabeac1274d3ad261604",
		"e9af0e7ca89330d2b8615d1b4137ca617e21297f2f0ded8e31b7d2ead8714660",
		"7b124583097f1029a0c74191fe7378c9105acc706695ed1493bb76034226a57b",
		"ec40057b995476650b3db98e9db75738a8cd2f94d863b906150c56aac19caa6b",
		"01d9ff729efd39d83784c0fe59c4ae81a67034cb53c943fb818b9d8ae7fc33e5",
		"00dfb3c696328c76424519a7befe8e0f6c76f947b52767916d24823f735baf2e",
		"461b799b4d9ceea8d580dcb76d11150d535e1639d16003c3fb7e9d1fd13083a8",
		"ee03039479e5228fdc551cbde7079d3412ea186a517ccc63e46e9fcce4fe3a6c",
		"a8cfb543524e7f02b9f045acd543c21c373b4c9b98ac20cec417a6ddb5744e94",
		"932b794bf89c6edaf5d0650c7c4bad9242b25626e37ead5aa75ec8c64e09dd4f",
		"16b10c779ce5cfef59c7710d2e68441ea6facb68e9b5f7d533ae0bb78e28bf57",
		"0f77c76743e7396f9910139f4937d837ae54e21038ac5c0b3fd6ef171a28a7e4",
		"d7e574b7b952f293e80dde905eb509373f3f6cd109a02208b3c1e924080a20ca",
		"45666f8c381e3da675563ff8ba23f83bfac30c34abdde6e5c0975ef9fd700cb9",
		"b24612e454607eb1aba447f816d1a4551ef95fa7247fb7c1f503020a7177f0dd",
		"7e208861856da42c8bb46a7567f8121362d9fb2496f131a4aa9017cf366cdfce",
		"5b646bff6ad1100165037a055601ea02358c0f41050f9dfe3c95dccbd3087be0",
		"746d1dccfed2f0ff1e13c51e2d50d5324375fbd5bf7ca82a8931828d801d43ab",
		"cb98110d4a6bb97d22feadbc6c0d8930c5f8fc508b2fc5b35328d26b88db19ae",
		"60b626a033b55f27d7676c4095eababc7a2c7ede2624b472e97f64f96b8cfc0e",
		"e5b52bc927468df71893eb8197ef820cf76cb0aaf6e8e4fe93ad62d803983104",
		"056541ae5da9961be2b0a5e895e5c5ba153cbb62dd561a427bad0ffd41923199",
		"f8fef05a3fa5c9f3eba41638b247b711a99f960fe73aa2f90136aeb20329b888",
	];

	//begin rct new functions
	//creates a Pedersen commitment from an amount (in scalar form) and a mask
	//C = bG + aH where b = mask, a = amount
	function commit(amount, mask) {
		if (
			!valid_hex(mask) ||
			mask.length !== 64 ||
			!valid_hex(amount) ||
			amount.length !== 64
		) {
			throw "invalid amount or mask!";
		}
		var C = this.ge_double_scalarmult_base_vartime(amount, H, mask);
		return C;
	}

	function zeroCommit(amount) {
		if (!valid_hex(amount) || amount.length !== 64) {
			throw "invalid amount!";
		}
		var C = this.ge_double_scalarmult_base_vartime(amount, H, I);
		return C;
	}

	this.decode_rct_ecdh = function(ecdh, key) {
		var first = this.hash_to_scalar(key);
		var second = this.hash_to_scalar(first);
		return {
			mask: this.sc_sub(ecdh.mask, first),
			amount: this.sc_sub(ecdh.amount, second),
		};
	};

	this.encode_rct_ecdh = function(ecdh, key) {
		var first = this.hash_to_scalar(key);
		var second = this.hash_to_scalar(first);
		return {
			mask: this.sc_add(ecdh.mask, first),
			amount: this.sc_add(ecdh.amount, second),
		};
	};

	//switch byte order for hex string
	function swapEndian(hex) {
		if (hex.length % 2 !== 0) {
			return "length must be a multiple of 2!";
		}
		var data = "";
		for (var i = 1; i <= hex.length / 2; i++) {
			data += hex.substr(0 - 2 * i, 2);
		}
		return data;
	}

	//switch byte order charwise
	function swapEndianC(string) {
		var data = "";
		for (var i = 1; i <= string.length; i++) {
			data += string.substr(0 - i, 1);
		}
		return data;
	}

	//for most uses you'll also want to swapEndian after conversion
	//mainly to convert integer "scalars" to usable hexadecimal strings
	function d2h(integer) {
		if (typeof integer !== "string" && integer.toString().length > 15) {
			throw "integer should be entered as a string for precision";
		}
		var padding = "";
		for (i = 0; i < 63; i++) {
			padding += "0";
		}
		return (
			padding +
			JSBigInt(integer)
				.toString(16)
				.toLowerCase()
		).slice(-64);
	}

	//integer (string) to scalar
	function d2s(integer) {
		return swapEndian(d2h(integer));
	}

	//scalar to integer (string)
	function s2d(scalar) {
		return JSBigInt.parse(swapEndian(scalar), 16).toString();
	}

	//convert integer string to 64bit "binary" little-endian string
	function d2b(integer) {
		if (typeof integer !== "string" && integer.toString().length > 15) {
			throw "integer should be entered as a string for precision";
		}
		var padding = "";
		for (i = 0; i < 63; i++) {
			padding += "0";
		}
		var a = new JSBigInt(integer);
		if (a.toString(2).length > 64) {
			throw "amount overflows uint64!";
		}
		return swapEndianC((padding + a.toString(2)).slice(-64));
	}

	//convert integer string to 64bit base 4 little-endian string
	function d2b4(integer) {
		if (typeof integer !== "string" && integer.toString().length > 15) {
			throw "integer should be entered as a string for precision";
		}
		var padding = "";
		for (i = 0; i < 31; i++) {
			padding += "0";
		}
		var a = new JSBigInt(integer);
		if (a.toString(2).length > 64) {
			throw "amount overflows uint64!";
		}
		return swapEndianC((padding + a.toString(4)).slice(-32));
	}
	//end rct new functions

	this.valid_hex = function(hex) {
		var exp = new RegExp("[0-9a-fA-F]{" + hex.length + "}");
		return exp.test(hex);
	};

	//simple exclusive or function for two hex inputs
	this.hex_xor = function(hex1, hex2) {
		if (
			!hex1 ||
			!hex2 ||
			hex1.length !== hex2.length ||
			hex1.length % 2 !== 0 ||
			hex2.length % 2 !== 0
		) {
			throw "Hex string(s) is/are invalid!";
		}
		var bin1 = hextobin(hex1);
		var bin2 = hextobin(hex2);
		var xor = new Uint8Array(bin1.length);
		for (i = 0; i < xor.length; i++) {
			xor[i] = bin1[i] ^ bin2[i];
		}
		return bintohex(xor);
	};

	function hextobin(hex) {
		if (hex.length % 2 !== 0) throw "Hex string has invalid length!";
		var res = new Uint8Array(hex.length / 2);
		for (var i = 0; i < hex.length / 2; ++i) {
			res[i] = parseInt(hex.slice(i * 2, i * 2 + 2), 16);
		}
		return res;
	}

	function bintohex(bin) {
		var out = [];
		for (var i = 0; i < bin.length; ++i) {
			out.push(("0" + bin[i].toString(16)).slice(-2));
		}
		return out.join("");
	}

	// Generate a 256-bit / 64-char / 32-byte crypto random
	this.rand_32 = function() {
		return mnemonic.mn_random(256);
	};

	// Generate a 128-bit / 32-char / 16-byte crypto random
	this.rand_16 = function() {
		return mnemonic.mn_random(128);
	};

	// Generate a 64-bit / 16-char / 8-byte crypto random
	this.rand_8 = function() {
		return mnemonic.mn_random(64);
	};

	this.encode_varint = function(i) {
		i = new JSBigInt(i);
		var out = "";
		// While i >= b10000000
		while (i.compare(0x80) >= 0) {
			// out.append i & b01111111 | b10000000
			out += ("0" + ((i.lowVal() & 0x7f) | 0x80).toString(16)).slice(-2);
			i = i.divide(new JSBigInt(2).pow(7));
		}
		out += ("0" + i.toJSValue().toString(16)).slice(-2);
		return out;
	};

	this.sc_reduce = function(hex) {
		var input = hextobin(hex);
		if (input.length !== 64) {
			throw "Invalid input length";
		}
		var mem = CNCrypto._malloc(64);
		CNCrypto.HEAPU8.set(input, mem);
		CNCrypto.ccall("sc_reduce", "void", ["number"], [mem]);
		var output = CNCrypto.HEAPU8.subarray(mem, mem + 64);
		CNCrypto._free(mem);
		return bintohex(output);
	};

	this.sc_reduce32 = function(hex) {
		var input = hextobin(hex);
		if (input.length !== 32) {
			throw "Invalid input length";
		}
		var mem = CNCrypto._malloc(32);
		CNCrypto.HEAPU8.set(input, mem);
		CNCrypto.ccall("sc_reduce32", "void", ["number"], [mem]);
		var output = CNCrypto.HEAPU8.subarray(mem, mem + 32);
		CNCrypto._free(mem);
		return bintohex(output);
	};

	this.cn_fast_hash = function(input, inlen) {
		/*if (inlen === undefined || !inlen) {
			inlen = Math.floor(input.length / 2);
		}*/
		if (input.length % 2 !== 0 || !this.valid_hex(input)) {
			throw "Input invalid";
		}
		//update to use new keccak impl (approx 45x faster)
		//var state = this.keccak(input, inlen, HASH_STATE_BYTES);
		//return state.substr(0, HASH_SIZE * 2);
		return sha3.keccak_256(hextobin(input));
	};

	//many functions below are commented out now, and duplicated with the faster nacl impl --luigi1111
	// to be removed completely later
	/*this.sec_key_to_pub = function(sec) {
		var input = hextobin(sec);
		if (input.length !== 32) {
			throw "Invalid input length";
		}
		var input_mem = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(input, input_mem);
		var ge_p3 = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var out_mem = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.ccall('ge_scalarmult_base', 'void', ['number', 'number'], [ge_p3, input_mem]);
		CNCrypto.ccall('ge_p3_tobytes', 'void', ['number', 'number'], [out_mem, ge_p3]);
		var output = CNCrypto.HEAPU8.subarray(out_mem, out_mem + KEY_SIZE);
		CNCrypto._free(ge_p3);
		CNCrypto._free(input_mem);
		CNCrypto._free(out_mem);
		return bintohex(output);
	};*/

	this.sec_key_to_pub = function(sec) {
		if (sec.length !== 64) {
			throw "Invalid sec length";
		}
		return bintohex(nacl.ll.ge_scalarmult_base(hextobin(sec)));
	};

	//alias
	this.ge_scalarmult_base = function(sec) {
		return this.sec_key_to_pub(sec);
	};

	//accepts arbitrary point, rather than G
	/*this.ge_scalarmult = function(pub, sec) {
		if (pub.length !== 64 || sec.length !== 64) {
			throw "Invalid input length";
		}
		var pub_b = hextobin(pub);
		var sec_b = hextobin(sec);
		var pub_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(pub_b, pub_m);
		var sec_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(sec_b, sec_m);
		var ge_p3_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var ge_p2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		if (CNCrypto.ccall("ge_frombytes_vartime", "bool", ["number", "number"], [ge_p3_m, pub_m]) !== 0) {
			throw "ge_frombytes_vartime returned non-zero error code";
		}
		CNCrypto.ccall("ge_scalarmult", "void", ["number", "number", "number"], [ge_p2_m, sec_m, ge_p3_m]);
		var derivation_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.ccall("ge_tobytes", "void", ["number", "number"], [derivation_m, ge_p2_m]);
		var res = CNCrypto.HEAPU8.subarray(derivation_m, derivation_m + KEY_SIZE);
		CNCrypto._free(pub_m);
		CNCrypto._free(sec_m);
		CNCrypto._free(ge_p3_m);
		CNCrypto._free(ge_p2_m);
		CNCrypto._free(derivation_m);
		return bintohex(res);
	};*/
	this.ge_scalarmult = function(pub, sec) {
		if (pub.length !== 64 || sec.length !== 64) {
			throw "Invalid input length";
		}
		return bintohex(nacl.ll.ge_scalarmult(hextobin(pub), hextobin(sec)));
	};

	this.pubkeys_to_string = function(spend, view, nettype) {
		var prefix = this.encode_varint(
			nettype_utils.cryptonoteBase58PrefixForStandardAddressOn(nettype),
		);
		var data = prefix + spend + view;
		var checksum = this.cn_fast_hash(data);
		return cnBase58.encode(
			data + checksum.slice(0, ADDRESS_CHECKSUM_SIZE * 2),
		);
	};

	this.new__int_addr_from_addr_and_short_pid = function(
		address,
		short_pid,
		nettype,
	) {
		// throws
		let decoded_address = this.decode_address(
			address, // TODO/FIXME: not super happy about having to decode just to re-encode… this was a quick hack
			nettype,
		); // throws
		if (!short_pid || short_pid.length != 16) {
			throw "expected valid short_pid";
		}
		var prefix = this.encode_varint(
			nettype_utils.cryptonoteBase58PrefixForIntegratedAddressOn(nettype),
		);
		var data =
			prefix + decoded_address.spend + decoded_address.view + short_pid;
		var checksum = this.cn_fast_hash(data);
		var encodable__data =
			data + checksum.slice(0, ADDRESS_CHECKSUM_SIZE * 2);
		//
		return cnBase58.encode(encodable__data);
	};

	// Generate keypair from seed
	this.generate_keys = function(seed) {
		if (seed.length !== 64) throw "Invalid input length!";
		var sec = this.sc_reduce32(seed);
		var pub = this.sec_key_to_pub(sec);
		return {
			sec: sec,
			pub: pub,
		};
	};

	this.random_keypair = function() {
		return this.generate_keys(this.rand_32());
	};

	// Random 32-byte ec scalar
	this.random_scalar = function() {
		//var rand = this.sc_reduce(mnemonic.mn_random(64 * 8));
		//return rand.slice(0, STRUCT_SIZES.EC_SCALAR * 2);
		return this.sc_reduce32(this.rand_32());
	};

	/* no longer used
	this.keccak = function(hex, inlen, outlen) {
		var input = hextobin(hex);
		if (input.length !== inlen) {
			throw "Invalid input length";
		}
		if (outlen <= 0) {
			throw "Invalid output length";
		}
		var input_mem = CNCrypto._malloc(inlen);
		CNCrypto.HEAPU8.set(input, input_mem);
		var out_mem = CNCrypto._malloc(outlen);
		CNCrypto._keccak(input_mem, inlen | 0, out_mem, outlen | 0);
		var output = CNCrypto.HEAPU8.subarray(out_mem, out_mem + outlen);
		CNCrypto._free(input_mem);
		CNCrypto._free(out_mem);
		return bintohex(output);
	};*/

	this.create_address = function(seed, nettype) {
		var keys = {};
		// updated by Luigi and PS to support reduced and non-reduced seeds
		var first;
		if (seed.length !== 64) {
			first = this.cn_fast_hash(seed);
		} else {
			first = this.sc_reduce32(seed);
		}
		keys.spend = this.generate_keys(first);
		var second = this.cn_fast_hash(first);
		keys.view = this.generate_keys(second);
		keys.public_addr = this.pubkeys_to_string(
			keys.spend.pub,
			keys.view.pub,
			nettype,
		);
		return keys;
	};

	this.create_addr_prefix = function(seed, nettype) {
		var first;
		if (seed.length !== 64) {
			first = this.cn_fast_hash(seed);
		} else {
			first = seed;
		}
		var spend = this.generate_keys(first);
		var prefix = this.encode_varint(
			nettype_utils.cryptonoteBase58PrefixForStandardAddressOn(nettype),
		);
		return cnBase58.encode(prefix + spend.pub).slice(0, 44);
	};

	this.decode_address = function(address, nettype) {
		var dec = cnBase58.decode(address);
		var expectedPrefix = this.encode_varint(
			nettype_utils.cryptonoteBase58PrefixForStandardAddressOn(nettype),
		);
		var expectedPrefixInt = this.encode_varint(
			nettype_utils.cryptonoteBase58PrefixForIntegratedAddressOn(nettype),
		);
		var expectedPrefixSub = this.encode_varint(
			nettype_utils.cryptonoteBase58PrefixForSubAddressOn(nettype),
		);
		var prefix = dec.slice(0, expectedPrefix.length);
		if (
			prefix !== expectedPrefix &&
			prefix !== expectedPrefixInt &&
			prefix !== expectedPrefixSub
		) {
			throw "Invalid address prefix";
		}
		dec = dec.slice(expectedPrefix.length);
		var spend = dec.slice(0, 64);
		var view = dec.slice(64, 128);
		if (prefix === expectedPrefixInt) {
			var intPaymentId = dec.slice(128, 128 + INTEGRATED_ID_SIZE * 2);
			var checksum = dec.slice(
				128 + INTEGRATED_ID_SIZE * 2,
				128 + INTEGRATED_ID_SIZE * 2 + ADDRESS_CHECKSUM_SIZE * 2,
			);
			var expectedChecksum = this.cn_fast_hash(
				prefix + spend + view + intPaymentId,
			).slice(0, ADDRESS_CHECKSUM_SIZE * 2);
		} else {
			var checksum = dec.slice(128, 128 + ADDRESS_CHECKSUM_SIZE * 2);
			var expectedChecksum = this.cn_fast_hash(
				prefix + spend + view,
			).slice(0, ADDRESS_CHECKSUM_SIZE * 2);
		}
		if (checksum !== expectedChecksum) {
			throw "Invalid checksum";
		}
		if (intPaymentId) {
			return {
				spend: spend,
				view: view,
				intPaymentId: intPaymentId,
			};
		} else {
			return {
				spend: spend,
				view: view,
			};
		}
	};

	this.is_subaddress = function(addr, nettype) {
		var decoded = cnBase58.decode(addr);
		var subaddressPrefix = this.encode_varint(
			nettype_utils.cryptonoteBase58PrefixForSubAddressOn(nettype),
		);
		var prefix = decoded.slice(0, subaddressPrefix.length);
		return prefix === subaddressPrefix;
	};

	this.valid_keys = function(view_pub, view_sec, spend_pub, spend_sec) {
		var expected_view_pub = this.sec_key_to_pub(view_sec);
		var expected_spend_pub = this.sec_key_to_pub(spend_sec);
		return (
			expected_spend_pub === spend_pub && expected_view_pub === view_pub
		);
	};

	this.hash_to_scalar = function(buf) {
		var hash = this.cn_fast_hash(buf);
		var scalar = this.sc_reduce32(hash);
		return scalar;
	};

	/*this.generate_key_derivation = function(pub, sec) {
		if (pub.length !== 64 || sec.length !== 64) {
			throw "Invalid input length";
		}
		var pub_b = hextobin(pub);
		var sec_b = hextobin(sec);
		var pub_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(pub_b, pub_m);
		var sec_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(sec_b, sec_m);
		var ge_p3_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var ge_p2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var ge_p1p1_m = CNCrypto._malloc(STRUCT_SIZES.GE_P1P1);
		if (CNCrypto.ccall("ge_frombytes_vartime", "bool", ["number", "number"], [ge_p3_m, pub_m]) !== 0) {
			throw "ge_frombytes_vartime returned non-zero error code";
		}
		CNCrypto.ccall("ge_scalarmult", "void", ["number", "number", "number"], [ge_p2_m, sec_m, ge_p3_m]);
		CNCrypto.ccall("ge_mul8", "void", ["number", "number"], [ge_p1p1_m, ge_p2_m]);
		CNCrypto.ccall("ge_p1p1_to_p2", "void", ["number", "number"], [ge_p2_m, ge_p1p1_m]);
		var derivation_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.ccall("ge_tobytes", "void", ["number", "number"], [derivation_m, ge_p2_m]);
		var res = CNCrypto.HEAPU8.subarray(derivation_m, derivation_m + KEY_SIZE);
		CNCrypto._free(pub_m);
		CNCrypto._free(sec_m);
		CNCrypto._free(ge_p3_m);
		CNCrypto._free(ge_p2_m);
		CNCrypto._free(ge_p1p1_m);
		CNCrypto._free(derivation_m);
		return bintohex(res);
	};*/

	this.generate_key_derivation = function(pub, sec) {
		if (pub.length !== 64 || sec.length !== 64) {
			throw "Invalid input length";
		}
		var P = this.ge_scalarmult(pub, sec);
		return this.ge_scalarmult(P, d2s(8)); //mul8 to ensure group
	};

	this.derivation_to_scalar = function(derivation, output_index) {
		var buf = "";
		if (derivation.length !== STRUCT_SIZES.EC_POINT * 2) {
			throw "Invalid derivation length!";
		}
		buf += derivation;
		var enc = encode_varint(output_index);
		if (enc.length > 10 * 2) {
			throw "output_index didn't fit in 64-bit varint";
		}
		buf += enc;
		return this.hash_to_scalar(buf);
	};

	this.derive_secret_key = function(derivation, out_index, sec) {
		if (derivation.length !== 64 || sec.length !== 64) {
			throw "Invalid input length!";
		}
		var scalar_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var scalar_b = hextobin(
			this.derivation_to_scalar(derivation, out_index),
		);
		CNCrypto.HEAPU8.set(scalar_b, scalar_m);
		var base_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(sec), base_m);
		var derived_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		CNCrypto.ccall(
			"sc_add",
			"void",
			["number", "number", "number"],
			[derived_m, base_m, scalar_m],
		);
		var res = CNCrypto.HEAPU8.subarray(
			derived_m,
			derived_m + STRUCT_SIZES.EC_SCALAR,
		);
		CNCrypto._free(scalar_m);
		CNCrypto._free(base_m);
		CNCrypto._free(derived_m);
		return bintohex(res);
	};

	/*this.derive_public_key = function(derivation, out_index, pub) {
		if (derivation.length !== 64 || pub.length !== 64) {
			throw "Invalid input length!";
		}
		var derivation_m = CNCrypto._malloc(KEY_SIZE);
		var derivation_b = hextobin(derivation);
		CNCrypto.HEAPU8.set(derivation_b, derivation_m);
		var base_m = CNCrypto._malloc(KEY_SIZE);
		var base_b = hextobin(pub);
		CNCrypto.HEAPU8.set(base_b, base_m);
		var point1_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var point2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var point3_m = CNCrypto._malloc(STRUCT_SIZES.GE_CACHED);
		var point4_m = CNCrypto._malloc(STRUCT_SIZES.GE_P1P1);
		var point5_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var derived_key_m = CNCrypto._malloc(KEY_SIZE);
		if (CNCrypto.ccall("ge_frombytes_vartime", "bool", ["number", "number"], [point1_m, base_m]) !== 0) {
			throw "ge_frombytes_vartime returned non-zero error code";
		}
		var scalar_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var scalar_b = hextobin(this.derivation_to_scalar(bintohex(CNCrypto.HEAPU8.subarray(derivation_m, derivation_m + STRUCT_SIZES.EC_POINT)), out_index));
		CNCrypto.HEAPU8.set(scalar_b, scalar_m);
		CNCrypto.ccall("ge_scalarmult_base", "void", ["number", "number"], [point2_m, scalar_m]);
		CNCrypto.ccall("ge_p3_to_cached", "void", ["number", "number"], [point3_m, point2_m]);
		CNCrypto.ccall("ge_add", "void", ["number", "number", "number"], [point4_m, point1_m, point3_m]);
		CNCrypto.ccall("ge_p1p1_to_p2", "void", ["number", "number"], [point5_m, point4_m]);
		CNCrypto.ccall("ge_tobytes", "void", ["number", "number"], [derived_key_m, point5_m]);
		var res = CNCrypto.HEAPU8.subarray(derived_key_m, derived_key_m + KEY_SIZE);
		CNCrypto._free(derivation_m);
		CNCrypto._free(base_m);
		CNCrypto._free(scalar_m);
		CNCrypto._free(point1_m);
		CNCrypto._free(point2_m);
		CNCrypto._free(point3_m);
		CNCrypto._free(point4_m);
		CNCrypto._free(point5_m);
		CNCrypto._free(derived_key_m);
		return bintohex(res);
	};*/

	this.derive_public_key = function(derivation, out_index, pub) {
		if (derivation.length !== 64 || pub.length !== 64) {
			throw "Invalid input length!";
		}
		var s = this.derivation_to_scalar(derivation, out_index);
		return bintohex(
			nacl.ll.ge_add(hextobin(pub), hextobin(this.ge_scalarmult_base(s))),
		);
	};

	// D' = P - Hs(aR|i)G
	this.derive_subaddress_public_key = function(
		output_key,
		derivation,
		out_index,
	) {
		if (output_key.length !== 64 || derivation.length !== 64) {
			throw "Invalid input length!";
		}
		var scalar = this.derivation_to_scalar(derivation, out_index);
		var point = this.ge_scalarmult_base(scalar);
		return this.ge_sub(output_key, point);
	};

	this.hash_to_ec = function(key) {
		if (key.length !== KEY_SIZE * 2) {
			throw "Invalid input length";
		}
		var h_m = CNCrypto._malloc(HASH_SIZE);
		var point_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var point2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P1P1);
		var res_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var hash = hextobin(this.cn_fast_hash(key, KEY_SIZE));
		CNCrypto.HEAPU8.set(hash, h_m);
		CNCrypto.ccall(
			"ge_fromfe_frombytes_vartime",
			"void",
			["number", "number"],
			[point_m, h_m],
		);
		CNCrypto.ccall(
			"ge_mul8",
			"void",
			["number", "number"],
			[point2_m, point_m],
		);
		CNCrypto.ccall(
			"ge_p1p1_to_p3",
			"void",
			["number", "number"],
			[res_m, point2_m],
		);
		var res = CNCrypto.HEAPU8.subarray(res_m, res_m + STRUCT_SIZES.GE_P3);
		CNCrypto._free(h_m);
		CNCrypto._free(point_m);
		CNCrypto._free(point2_m);
		CNCrypto._free(res_m);
		return bintohex(res);
	};

	//returns a 32 byte point via "ge_p3_tobytes" rather than a 160 byte "p3", otherwise same as above;
	this.hash_to_ec_2 = function(key) {
		if (key.length !== KEY_SIZE * 2) {
			throw "Invalid input length";
		}
		var h_m = CNCrypto._malloc(HASH_SIZE);
		var point_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var point2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P1P1);
		var res_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var hash = hextobin(this.cn_fast_hash(key, KEY_SIZE));
		var res2_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hash, h_m);
		CNCrypto.ccall(
			"ge_fromfe_frombytes_vartime",
			"void",
			["number", "number"],
			[point_m, h_m],
		);
		CNCrypto.ccall(
			"ge_mul8",
			"void",
			["number", "number"],
			[point2_m, point_m],
		);
		CNCrypto.ccall(
			"ge_p1p1_to_p3",
			"void",
			["number", "number"],
			[res_m, point2_m],
		);
		CNCrypto.ccall(
			"ge_p3_tobytes",
			"void",
			["number", "number"],
			[res2_m, res_m],
		);
		var res = CNCrypto.HEAPU8.subarray(res2_m, res2_m + KEY_SIZE);
		CNCrypto._free(h_m);
		CNCrypto._free(point_m);
		CNCrypto._free(point2_m);
		CNCrypto._free(res_m);
		CNCrypto._free(res2_m);
		return bintohex(res);
	};

	this.generate_key_image_2 = function(pub, sec) {
		if (!pub || !sec || pub.length !== 64 || sec.length !== 64) {
			throw "Invalid input length";
		}
		var pub_m = CNCrypto._malloc(KEY_SIZE);
		var sec_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(pub), pub_m);
		CNCrypto.HEAPU8.set(hextobin(sec), sec_m);
		if (CNCrypto.ccall("sc_check", "number", ["number"], [sec_m]) !== 0) {
			throw "sc_check(sec) != 0";
		}
		var point_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var point2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var point_b = hextobin(this.hash_to_ec(pub));
		CNCrypto.HEAPU8.set(point_b, point_m);
		var image_m = CNCrypto._malloc(STRUCT_SIZES.KEY_IMAGE);
		CNCrypto.ccall(
			"ge_scalarmult",
			"void",
			["number", "number", "number"],
			[point2_m, sec_m, point_m],
		);
		CNCrypto.ccall(
			"ge_tobytes",
			"void",
			["number", "number"],
			[image_m, point2_m],
		);
		var res = CNCrypto.HEAPU8.subarray(
			image_m,
			image_m + STRUCT_SIZES.KEY_IMAGE,
		);
		CNCrypto._free(pub_m);
		CNCrypto._free(sec_m);
		CNCrypto._free(point_m);
		CNCrypto._free(point2_m);
		CNCrypto._free(image_m);
		return bintohex(res);
	};

	this.generate_key_image = function(
		tx_pub,
		view_sec,
		spend_pub,
		spend_sec,
		output_index,
	) {
		if (tx_pub.length !== 64) {
			throw "Invalid tx_pub length";
		}
		if (view_sec.length !== 64) {
			throw "Invalid view_sec length";
		}
		if (spend_pub.length !== 64) {
			throw "Invalid spend_pub length";
		}
		if (spend_sec.length !== 64) {
			throw "Invalid spend_sec length";
		}
		var recv_derivation = this.generate_key_derivation(tx_pub, view_sec);
		var ephemeral_pub = this.derive_public_key(
			recv_derivation,
			output_index,
			spend_pub,
		);
		var ephemeral_sec = this.derive_secret_key(
			recv_derivation,
			output_index,
			spend_sec,
		);
		var k_image = this.generate_key_image_2(ephemeral_pub, ephemeral_sec);
		return {
			ephemeral_pub: ephemeral_pub,
			key_image: k_image,
		};
	};

	this.generate_key_image_helper_rct = function(
		keys,
		tx_pub_key,
		out_index,
		enc_mask,
	) {
		var recv_derivation = this.generate_key_derivation(
			tx_pub_key,
			keys.view.sec,
		);
		if (!recv_derivation) throw "Failed to generate key image";
		var mask = enc_mask
			? sc_sub(
					enc_mask,
					hash_to_scalar(
						derivation_to_scalar(recv_derivation, out_index),
					),
			  )
			: I; //decode mask, or d2s(1) if no mask
		var ephemeral_pub = this.derive_public_key(
			recv_derivation,
			out_index,
			keys.spend.pub,
		);
		if (!ephemeral_pub) throw "Failed to generate key image";
		var ephemeral_sec = this.derive_secret_key(
			recv_derivation,
			out_index,
			keys.spend.sec,
		);
		var image = this.generate_key_image_2(ephemeral_pub, ephemeral_sec);
		return {
			in_ephemeral: {
				pub: ephemeral_pub,
				sec: ephemeral_sec,
				mask: mask,
			},
			image: image,
		};
	};

	//curve and scalar functions; split out to make their host functions cleaner and more readable
	//inverts X coordinate -- this seems correct ^_^ -luigi1111
	this.ge_neg = function(point) {
		if (point.length !== 64) {
			throw "expected 64 char hex string";
		}
		return (
			point.slice(0, 62) +
			((parseInt(point.slice(62, 63), 16) + 8) % 16).toString(16) +
			point.slice(63, 64)
		);
	};

	//adds two points together, order does not matter
	/*this.ge_add2 = function(point1, point2) {
		var point1_m = CNCrypto._malloc(KEY_SIZE);
		var point2_m = CNCrypto._malloc(KEY_SIZE);
		var point1_m2 = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var point2_m2 = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		CNCrypto.HEAPU8.set(hextobin(point1), point1_m);
		CNCrypto.HEAPU8.set(hextobin(point2), point2_m);
		if (CNCrypto.ccall("ge_frombytes_vartime", "bool", ["number", "number"], [point1_m2, point1_m]) !== 0) {
			throw "ge_frombytes_vartime returned non-zero error code";
		}
		if (CNCrypto.ccall("ge_frombytes_vartime", "bool", ["number", "number"], [point2_m2, point2_m]) !== 0) {
			throw "ge_frombytes_vartime returned non-zero error code";
		}
		var sum_m = CNCrypto._malloc(KEY_SIZE);
		var p2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var p1_m = CNCrypto._malloc(STRUCT_SIZES.GE_P1P1);
		var p3_m = CNCrypto._malloc(STRUCT_SIZES.GE_CACHED);
		CNCrypto.ccall("ge_p3_to_cached", "void", ["number", "number"], [p3_m, point2_m2]);
		CNCrypto.ccall("ge_add", "void", ["number", "number", "number"], [p1_m, point1_m2, p3_m]);
		CNCrypto.ccall("ge_p1p1_to_p2", "void", ["number", "number"], [p2_m, p1_m]);
		CNCrypto.ccall("ge_tobytes", "void", ["number", "number"], [sum_m, p2_m]);
		var res = CNCrypto.HEAPU8.subarray(sum_m, sum_m + KEY_SIZE);
		CNCrypto._free(point1_m);
		CNCrypto._free(point1_m2);
		CNCrypto._free(point2_m);
		CNCrypto._free(point2_m2);
		CNCrypto._free(p2_m);
		CNCrypto._free(p1_m);
		CNCrypto._free(sum_m);
		CNCrypto._free(p3_m);
		return bintohex(res);
	};*/

	this.ge_add = function(p1, p2) {
		if (p1.length !== 64 || p2.length !== 64) {
			throw "Invalid input length!";
		}
		return bintohex(nacl.ll.ge_add(hextobin(p1), hextobin(p2)));
	};

	//order matters
	this.ge_sub = function(point1, point2) {
		point2n = ge_neg(point2);
		return ge_add(point1, point2n);
	};

	//adds two scalars together
	this.sc_add = function(scalar1, scalar2) {
		if (scalar1.length !== 64 || scalar2.length !== 64) {
			throw "Invalid input length!";
		}
		var scalar1_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var scalar2_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		CNCrypto.HEAPU8.set(hextobin(scalar1), scalar1_m);
		CNCrypto.HEAPU8.set(hextobin(scalar2), scalar2_m);
		var derived_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		CNCrypto.ccall(
			"sc_add",
			"void",
			["number", "number", "number"],
			[derived_m, scalar1_m, scalar2_m],
		);
		var res = CNCrypto.HEAPU8.subarray(
			derived_m,
			derived_m + STRUCT_SIZES.EC_SCALAR,
		);
		CNCrypto._free(scalar1_m);
		CNCrypto._free(scalar2_m);
		CNCrypto._free(derived_m);
		return bintohex(res);
	};

	//subtracts one scalar from another
	this.sc_sub = function(scalar1, scalar2) {
		if (scalar1.length !== 64 || scalar2.length !== 64) {
			throw "Invalid input length!";
		}
		var scalar1_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var scalar2_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		CNCrypto.HEAPU8.set(hextobin(scalar1), scalar1_m);
		CNCrypto.HEAPU8.set(hextobin(scalar2), scalar2_m);
		var derived_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		CNCrypto.ccall(
			"sc_sub",
			"void",
			["number", "number", "number"],
			[derived_m, scalar1_m, scalar2_m],
		);
		var res = CNCrypto.HEAPU8.subarray(
			derived_m,
			derived_m + STRUCT_SIZES.EC_SCALAR,
		);
		CNCrypto._free(scalar1_m);
		CNCrypto._free(scalar2_m);
		CNCrypto._free(derived_m);
		return bintohex(res);
	};

	//fun mul function
	this.sc_mul = function(scalar1, scalar2) {
		if (scalar1.length !== 64 || scalar2.length !== 64) {
			throw "Invalid input length!";
		}
		return d2s(
			JSBigInt(s2d(scalar1))
				.multiply(JSBigInt(s2d(scalar2)))
				.remainder(l)
				.toString(),
		);
	};

	//res = c - (ab) mod l; argument names copied from the signature implementation
	this.sc_mulsub = function(sigc, sec, k) {
		if (
			k.length !== KEY_SIZE * 2 ||
			sigc.length !== KEY_SIZE * 2 ||
			sec.length !== KEY_SIZE * 2 ||
			!this.valid_hex(k) ||
			!this.valid_hex(sigc) ||
			!this.valid_hex(sec)
		) {
			throw "bad scalar";
		}
		var sec_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(sec), sec_m);
		var sigc_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(sigc), sigc_m);
		var k_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(k), k_m);
		var res_m = CNCrypto._malloc(KEY_SIZE);

		CNCrypto.ccall(
			"sc_mulsub",
			"void",
			["number", "number", "number", "number"],
			[res_m, sigc_m, sec_m, k_m],
		);
		res = CNCrypto.HEAPU8.subarray(res_m, res_m + KEY_SIZE);
		CNCrypto._free(k_m);
		CNCrypto._free(sec_m);
		CNCrypto._free(sigc_m);
		CNCrypto._free(res_m);
		return bintohex(res);
	};

	//res = aB + cG; argument names copied from the signature implementation
	/*this.ge_double_scalarmult_base_vartime = function(sigc, pub, sigr) {
		var pub_m = CNCrypto._malloc(KEY_SIZE);
		var pub2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		CNCrypto.HEAPU8.set(hextobin(pub), pub_m);
		if (CNCrypto.ccall("ge_frombytes_vartime", "void", ["number", "number"], [pub2_m, pub_m]) !== 0) {
			throw "Failed to call ge_frombytes_vartime";
		}
		var sigc_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(sigc), sigc_m);
		var sigr_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(sigr), sigr_m);
		if (CNCrypto.ccall("sc_check", "number", ["number"], [sigc_m]) !== 0 || CNCrypto.ccall("sc_check", "number", ["number"], [sigr_m]) !== 0) {
			throw "bad scalar(s)";
		}
		var tmp_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var res_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.ccall("ge_double_scalarmult_base_vartime", "void", ["number", "number", "number", "number"], [tmp_m, sigc_m, pub2_m, sigr_m]);
		CNCrypto.ccall("ge_tobytes", "void", ["number", "number"], [res_m, tmp_m]);
		var res = CNCrypto. HEAPU8.subarray(res_m, res_m + KEY_SIZE);
		CNCrypto._free(pub_m);
		CNCrypto._free(pub2_m);
		CNCrypto._free(sigc_m);
		CNCrypto._free(sigr_m);
		CNCrypto._free(tmp_m);
		CNCrypto._free(res_m);
		return bintohex(res);
	};*/

	this.ge_double_scalarmult_base_vartime = function(c, P, r) {
		if (c.length !== 64 || P.length !== 64 || r.length !== 64) {
			throw "Invalid input length!";
		}
		return bintohex(
			nacl.ll.ge_double_scalarmult_base_vartime(
				hextobin(c),
				hextobin(P),
				hextobin(r),
			),
		);
	};

	//res = a * Hp(B) + c*D
	//res = sigr * Hp(pub) + sigc * k_image; argument names also copied from the signature implementation; note precomp AND hash_to_ec are done internally!!
	/*this.ge_double_scalarmult_postcomp_vartime = function(sigr, pub, sigc, k_image) {
		var image_m = CNCrypto._malloc(STRUCT_SIZES.KEY_IMAGE);
		CNCrypto.HEAPU8.set(hextobin(k_image), image_m);
		var image_unp_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var image_pre_m = CNCrypto._malloc(STRUCT_SIZES.GE_DSMP);
		var tmp3_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var sigr_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var sigc_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var tmp2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var res_m = CNCrypto._malloc(STRUCT_SIZES.EC_POINT);
		if (CNCrypto.ccall("ge_frombytes_vartime", "void", ["number", "number"], [image_unp_m, image_m]) !== 0) {
			throw "Failed to call ge_frombytes_vartime";
		}
		CNCrypto.ccall("ge_dsm_precomp", "void", ["number", "number"], [image_pre_m, image_unp_m]);
		var ec = this.hash_to_ec(pub);
		CNCrypto.HEAPU8.set(hextobin(ec), tmp3_m);
		CNCrypto.HEAPU8.set(hextobin(sigc), sigc_m);
		CNCrypto.HEAPU8.set(hextobin(sigr), sigr_m);
		CNCrypto.ccall("ge_double_scalarmult_precomp_vartime", "void", ["number", "number", "number", "number", "number"], [tmp2_m, sigr_m, tmp3_m, sigc_m, image_pre_m]);
		CNCrypto.ccall("ge_tobytes", "void", ["number", "number"], [res_m, tmp2_m]);
		var res = CNCrypto. HEAPU8.subarray(res_m, res_m + STRUCT_SIZES.EC_POINT);
		CNCrypto._free(image_m);
		CNCrypto._free(image_unp_m);
		CNCrypto._free(image_pre_m);
		CNCrypto._free(tmp3_m);
		CNCrypto._free(sigr_m);
		CNCrypto._free(sigc_m);
		CNCrypto._free(tmp2_m);
		CNCrypto._free(res_m);
		return bintohex(res);
	};*/

	this.ge_double_scalarmult_postcomp_vartime = function(r, P, c, I) {
		if (
			c.length !== 64 ||
			P.length !== 64 ||
			r.length !== 64 ||
			I.length !== 64
		) {
			throw "Invalid input length!";
		}
		var Pb = this.hash_to_ec_2(P);
		return bintohex(
			nacl.ll.ge_double_scalarmult_postcomp_vartime(
				hextobin(r),
				hextobin(Pb),
				hextobin(c),
				hextobin(I),
			),
		);
	};

	//begin RCT functions

	//xv: vector of secret keys, 1 per ring (nrings)
	//pm: matrix of pubkeys, indexed by size first
	//iv: vector of indexes, 1 per ring (nrings), can be a string
	//size: ring size
	//nrings: number of rings
	//extensible borromean signatures
	this.genBorromean = function(xv, pm, iv, size, nrings) {
		if (xv.length !== nrings) {
			throw "wrong xv length " + xv.length;
		}
		if (pm.length !== size) {
			throw "wrong pm size " + pm.length;
		}
		for (var i = 0; i < pm.length; i++) {
			if (pm[i].length !== nrings) {
				throw "wrong pm[" + i + "] length " + pm[i].length;
			}
		}
		if (iv.length !== nrings) {
			throw "wrong iv length " + iv.length;
		}
		for (var i = 0; i < iv.length; i++) {
			if (iv[i] >= size) {
				throw "bad indices value at: " + i + ": " + iv[i];
			}
		}
		//signature struct
		var bb = {
			s: [],
			ee: "",
		};
		//signature pubkey matrix
		var L = [];
		//add needed sub vectors (1 per ring size)
		for (var i = 0; i < size; i++) {
			bb.s[i] = [];
			L[i] = [];
		}
		//compute starting at the secret index to the last row
		var index;
		var alpha = [];
		for (var i = 0; i < nrings; i++) {
			index = parseInt(iv[i]);
			alpha[i] = random_scalar();
			L[index][i] = ge_scalarmult_base(alpha[i]);
			for (var j = index + 1; j < size; j++) {
				bb.s[j][i] = random_scalar();
				var c = hash_to_scalar(L[j - 1][i]);
				L[j][i] = ge_double_scalarmult_base_vartime(
					c,
					pm[j][i],
					bb.s[j][i],
				);
			}
		}
		//hash last row to create ee
		var ltemp = "";
		for (var i = 0; i < nrings; i++) {
			ltemp += L[size - 1][i];
		}
		bb.ee = hash_to_scalar(ltemp);
		//compute the rest from 0 to secret index
		for (var i = 0; i < nrings; i++) {
			var cc = bb.ee;
			for (var j = 0; j < iv[i]; j++) {
				bb.s[j][i] = random_scalar();
				var LL = ge_double_scalarmult_base_vartime(
					cc,
					pm[j][i],
					bb.s[j][i],
				);
				cc = hash_to_scalar(LL);
			}
			bb.s[j][i] = sc_mulsub(xv[i], cc, alpha[i]);
		}
		return bb;
	};

	//proveRange
	//proveRange gives C, and mask such that \sumCi = C
	//	 c.f. http://eprint.iacr.org/2015/1098 section 5.1
	//	 and Ci is a commitment to either 0 or s^i, i=0,...,n
	//	 thus this proves that "amount" is in [0, s^n] (we assume s to be 4) (2 for now with v2 txes)
	//	 mask is a such that C = aG + bH, and b = amount
	//commitMaskObj = {C: commit, mask: mask}
	this.proveRange = function(
		commitMaskObj,
		amount,
		nrings,
		enc_seed,
		exponent,
	) {
		var size = 2;
		var C = I; //identity
		var mask = Z; //zero scalar
		var indices = d2b(amount); //base 2 for now
		var sig = {
			Ci: [],
			//exp: exponent //doesn't exist for now
		};
		/*payload stuff - ignore for now
		seeds = new Array(3);
		for (var i = 0; i < seeds.length; i++){
		seeds[i] = new Array(1);
		}
		genSeeds(seeds, enc_seed);
		*/
		var ai = [];
		var PM = [];
		for (var i = 0; i < size; i++) {
			PM[i] = [];
		}
		var j;
		//start at index and fill PM left and right -- PM[0] holds Ci
		for (i = 0; i < nrings; i++) {
			ai[i] = random_scalar();
			j = indices[i];
			PM[j][i] = ge_scalarmult_base(ai[i]);
			while (j > 0) {
				j--;
				PM[j][i] = ge_add(PM[j + 1][i], H2[i]); //will need to use i*2 for base 4 (or different object)
			}
			j = indices[i];
			while (j < size - 1) {
				j++;
				PM[j][i] = ge_sub(PM[j - 1][i], H2[i]); //will need to use i*2 for base 4 (or different object)
			}
			mask = sc_add(mask, ai[i]);
		}
		/*
		* some more payload stuff here
		*/
		//copy commitments to sig and sum them to commitment
		for (i = 0; i < nrings; i++) {
			//if (i < nrings - 1) //for later version
			sig.Ci[i] = PM[0][i];
			C = ge_add(C, PM[0][i]);
		}
		/* exponent stuff - ignore for now
		if (exponent){
		n = JSBigInt(10);
		n = n.pow(exponent).toString();
		mask = sc_mul(mask, d2s(n)); //new sum
		}
		*/
		sig.bsig = this.genBorromean(ai, PM, indices, size, nrings);
		commitMaskObj.C = C;
		commitMaskObj.mask = mask;
		return sig;
	};

	function array_hash_to_scalar(array) {
		var buf = "";
		for (var i = 0; i < array.length; i++) {
			if (typeof array[i] !== "string") {
				throw "unexpected array element";
			}
			buf += array[i];
		}
		return hash_to_scalar(buf);
	}

	// Gen creates a signature which proves that for some column in the keymatrix "pk"
	//	 the signer knows a secret key for each row in that column
	// we presently only support matrices of 2 rows (pubkey, commitment)
	// this is a simplied MLSAG_Gen function to reflect that
	// because we don't want to force same secret column for all inputs
	this.MLSAG_Gen = function(message, pk, xx, kimg, index) {
		var cols = pk.length; //ring size
		if (index >= cols) {
			throw "index out of range";
		}
		var rows = pk[0].length; //number of signature rows (always 2)
		if (rows !== 2) {
			throw "wrong row count";
		}
		for (var i = 0; i < cols; i++) {
			if (pk[i].length !== rows) {
				throw "pk is not rectangular";
			}
		}
		if (xx.length !== rows) {
			throw "bad xx size";
		}

		var c_old = "";
		var alpha = [];

		var rv = {
			ss: [],
			cc: null,
		};
		for (i = 0; i < cols; i++) {
			rv.ss[i] = [];
		}
		var toHash = []; //holds 6 elements: message, pubkey, dsRow L, dsRow R, commitment, ndsRow L
		toHash[0] = message;

		//secret index (pubkey section)
		alpha[0] = random_scalar(); //need to save alphas for later
		toHash[1] = pk[index][0]; //secret index pubkey
		toHash[2] = ge_scalarmult_base(alpha[0]); //dsRow L
		toHash[3] = generate_key_image_2(pk[index][0], alpha[0]); //dsRow R (key image check)
		//secret index (commitment section)
		alpha[1] = random_scalar();
		toHash[4] = pk[index][1]; //secret index commitment
		toHash[5] = ge_scalarmult_base(alpha[1]); //ndsRow L

		c_old = array_hash_to_scalar(toHash);

		i = (index + 1) % cols;
		if (i === 0) {
			rv.cc = c_old;
		}
		while (i != index) {
			rv.ss[i][0] = random_scalar(); //dsRow ss
			rv.ss[i][1] = random_scalar(); //ndsRow ss

			//!secret index (pubkey section)
			toHash[1] = pk[i][0];
			toHash[2] = ge_double_scalarmult_base_vartime(
				c_old,
				pk[i][0],
				rv.ss[i][0],
			);
			toHash[3] = ge_double_scalarmult_postcomp_vartime(
				rv.ss[i][0],
				pk[i][0],
				c_old,
				kimg,
			);
			//!secret index (commitment section)
			toHash[4] = pk[i][1];
			toHash[5] = ge_double_scalarmult_base_vartime(
				c_old,
				pk[i][1],
				rv.ss[i][1],
			);
			c_old = array_hash_to_scalar(toHash); //hash to get next column c
			i = (i + 1) % cols;
			if (i === 0) {
				rv.cc = c_old;
			}
		}
		for (i = 0; i < rows; i++) {
			rv.ss[index][i] = sc_mulsub(c_old, xx[i], alpha[i]);
		}
		return rv;
	};

	//prepares for MLSAG_Gen
	this.proveRctMG = function(message, pubs, inSk, kimg, mask, Cout, index) {
		var cols = pubs.length;
		if (cols < 3) {
			throw "cols must be > 2 (mixin)";
		}
		var xx = [];
		var PK = [];
		//fill pubkey matrix (copy destination, subtract commitments)
		for (var i = 0; i < cols; i++) {
			PK[i] = [];
			PK[i][0] = pubs[i].dest;
			PK[i][1] = ge_sub(pubs[i].mask, Cout);
		}
		xx[0] = inSk.x;
		xx[1] = sc_sub(inSk.a, mask);
		return this.MLSAG_Gen(message, PK, xx, kimg, index);
	};

	this.get_pre_mlsag_hash = function(rv) {
		var hashes = "";
		hashes += rv.message;
		hashes += this.cn_fast_hash(this.serialize_rct_base(rv));
		var buf = serialize_range_proofs(rv);
		hashes += this.cn_fast_hash(buf);
		return this.cn_fast_hash(hashes);
	};

	function serialize_range_proofs(rv) {
		var buf = "";
		for (var i = 0; i < rv.p.rangeSigs.length; i++) {
			for (var j = 0; j < rv.p.rangeSigs[i].bsig.s.length; j++) {
				for (var l = 0; l < rv.p.rangeSigs[i].bsig.s[j].length; l++) {
					buf += rv.p.rangeSigs[i].bsig.s[j][l];
				}
			}
			buf += rv.p.rangeSigs[i].bsig.ee;
			for (j = 0; j < rv.p.rangeSigs[i].Ci.length; j++) {
				buf += rv.p.rangeSigs[i].Ci[j];
			}
		}
		return buf;
	}

	//message is normal prefix hash
	//inSk is vector of x,a
	//kimg is vector of kimg
	//destinations is vector of pubkeys (we skip and proxy outAmounts instead)
	//inAmounts is vector of strings
	//outAmounts is vector of strings
	//mixRing is matrix of pubkey, commit (dest, mask)
	//amountKeys is vector of scalars
	//indices is vector
	//txnFee is string
	this.genRct = function(
		message,
		inSk,
		kimg,
		/*destinations, */ inAmounts,
		outAmounts,
		mixRing,
		amountKeys,
		indices,
		txnFee,
	) {
		if (outAmounts.length !== amountKeys.length) {
			throw "different number of amounts/amount_keys";
		}
		for (var i = 0; i < mixRing.length; i++) {
			if (mixRing[i].length <= indices[i]) {
				throw "bad mixRing/index size";
			}
		}
		if (mixRing.length !== inSk.length) {
			throw "mismatched mixRing/inSk";
		}
		if (inAmounts.length !== inSk.length) {
			throw "mismatched inAmounts/inSk";
		}
		if (indices.length !== inSk.length) {
			throw "mismatched indices/inSk";
		}

		rv = {
			type: inSk.length === 1 ? RCTTypeFull : RCTTypeSimple,
			message: message,
			outPk: [],
			p: {
				rangeSigs: [],
				MGs: [],
			},
			ecdhInfo: [],
			txnFee: txnFee.toString(),
			pseudoOuts: [],
		};

		var sumout = Z;
		var cmObj = {
			C: null,
			mask: null,
		};
		var nrings = 64; //for base 2/current
		//compute range proofs, etc
		for (i = 0; i < outAmounts.length; i++) {
			var teststart = new Date().getTime();
			rv.p.rangeSigs[i] = this.proveRange(
				cmObj,
				outAmounts[i],
				nrings,
				0,
				0,
			);
			var testfinish = new Date().getTime() - teststart;
			console.log("Time take for range proof " + i + ": " + testfinish);
			rv.outPk[i] = cmObj.C;
			sumout = sc_add(sumout, cmObj.mask);
			rv.ecdhInfo[i] = this.encode_rct_ecdh(
				{ mask: cmObj.mask, amount: d2s(outAmounts[i]) },
				amountKeys[i],
			);
		}

		//simple
		if (rv.type === 2) {
			var ai = [];
			var sumpouts = Z;
			//create pseudoOuts
			for (i = 0; i < inAmounts.length - 1; i++) {
				ai[i] = random_scalar();
				sumpouts = sc_add(sumpouts, ai[i]);
				rv.pseudoOuts[i] = commit(d2s(inAmounts[i]), ai[i]);
			}
			ai[i] = sc_sub(sumout, sumpouts);
			rv.pseudoOuts[i] = commit(d2s(inAmounts[i]), ai[i]);
			var full_message = this.get_pre_mlsag_hash(rv);
			for (i = 0; i < inAmounts.length; i++) {
				rv.p.MGs.push(
					this.proveRctMG(
						full_message,
						mixRing[i],
						inSk[i],
						kimg[i],
						ai[i],
						rv.pseudoOuts[i],
						indices[i],
					),
				);
			}
		} else {
			var sumC = I;
			//get sum of output commitments to use in MLSAG
			for (i = 0; i < rv.outPk.length; i++) {
				sumC = ge_add(sumC, rv.outPk[i]);
			}
			sumC = ge_add(sumC, ge_scalarmult(H, d2s(rv.txnFee)));
			var full_message = this.get_pre_mlsag_hash(rv);
			rv.p.MGs.push(
				this.proveRctMG(
					full_message,
					mixRing[0],
					inSk[0],
					kimg[0],
					sumout,
					sumC,
					indices[0],
				),
			);
		}
		return rv;
	};

	//end RCT functions

	this.add_pub_key_to_extra = function(extra, pubkey) {
		if (pubkey.length !== 64) throw "Invalid pubkey length";
		// Append pubkey tag and pubkey
		extra += TX_EXTRA_TAGS.PUBKEY + pubkey;
		return extra;
	};

	this.add_nonce_to_extra = function(extra, nonce) {
		// Append extra nonce
		if (nonce.length % 2 !== 0) {
			throw "Invalid extra nonce";
		}
		if (nonce.length / 2 > TX_EXTRA_NONCE_MAX_COUNT) {
			throw "Extra nonce must be at most " +
				TX_EXTRA_NONCE_MAX_COUNT +
				" bytes";
		}
		// Add nonce tag
		extra += TX_EXTRA_TAGS.NONCE;
		// Encode length of nonce
		extra += ("0" + (nonce.length / 2).toString(16)).slice(-2);
		// Write nonce
		extra += nonce;
		return extra;
	};

	this.get_payment_id_nonce = function(payment_id, pid_encrypt) {
		if (payment_id.length !== 64 && payment_id.length !== 16) {
			throw "Invalid payment id";
		}
		var res = "";
		if (pid_encrypt) {
			res += TX_EXTRA_NONCE_TAGS.ENCRYPTED_PAYMENT_ID;
		} else {
			res += TX_EXTRA_NONCE_TAGS.PAYMENT_ID;
		}
		res += payment_id;
		return res;
	};

	this.abs_to_rel_offsets = function(offsets) {
		if (offsets.length === 0) return offsets;
		for (var i = offsets.length - 1; i >= 1; --i) {
			offsets[i] = new JSBigInt(offsets[i])
				.subtract(offsets[i - 1])
				.toString();
		}
		return offsets;
	};

	this.get_tx_prefix_hash = function(tx) {
		var prefix = this.serialize_tx(tx, true);
		return this.cn_fast_hash(prefix);
	};

	this.get_tx_hash = function(tx) {
		if (typeof tx === "string") {
			return this.cn_fast_hash(tx);
		} else {
			return this.cn_fast_hash(this.serialize_tx(tx));
		}
	};

	this.serialize_tx = function(tx, headeronly) {
		//tx: {
		//	version: uint64,
		//	unlock_time: uint64,
		//	extra: hex,
		//	vin: [{amount: uint64, k_image: hex, key_offsets: [uint64,..]},...],
		//	vout: [{amount: uint64, target: {key: hex}},...],
		//	signatures: [[s,s,...],...]
		//}
		if (headeronly === undefined) {
			headeronly = false;
		}
		var buf = "";
		buf += this.encode_varint(tx.version);
		buf += this.encode_varint(tx.unlock_time);
		buf += this.encode_varint(tx.vin.length);
		var i, j;
		for (i = 0; i < tx.vin.length; i++) {
			var vin = tx.vin[i];
			switch (vin.type) {
				case "input_to_key":
					buf += "02";
					buf += this.encode_varint(vin.amount);
					buf += this.encode_varint(vin.key_offsets.length);
					for (j = 0; j < vin.key_offsets.length; j++) {
						buf += this.encode_varint(vin.key_offsets[j]);
					}
					buf += vin.k_image;
					break;
				default:
					throw "Unhandled vin type: " + vin.type;
			}
		}
		buf += this.encode_varint(tx.vout.length);
		for (i = 0; i < tx.vout.length; i++) {
			var vout = tx.vout[i];
			buf += this.encode_varint(vout.amount);
			switch (vout.target.type) {
				case "txout_to_key":
					buf += "02";
					buf += vout.target.key;
					break;
				default:
					throw "Unhandled txout target type: " + vout.target.type;
			}
		}
		if (!this.valid_hex(tx.extra)) {
			throw "Tx extra has invalid hex";
		}
		buf += this.encode_varint(tx.extra.length / 2);
		buf += tx.extra;
		if (!headeronly) {
			if (tx.vin.length !== tx.signatures.length) {
				throw "Signatures length != vin length";
			}
			for (i = 0; i < tx.vin.length; i++) {
				for (j = 0; j < tx.signatures[i].length; j++) {
					buf += tx.signatures[i][j];
				}
			}
		}
		return buf;
	};

	this.serialize_rct_tx_with_hash = function(tx) {
		var hashes = "";
		var buf = "";
		buf += this.serialize_tx(tx, true);
		hashes += this.cn_fast_hash(buf);
		var buf2 = this.serialize_rct_base(tx.rct_signatures);
		hashes += this.cn_fast_hash(buf2);
		buf += buf2;
		var buf3 = serialize_range_proofs(tx.rct_signatures);
		//add MGs
		for (var i = 0; i < tx.rct_signatures.p.MGs.length; i++) {
			for (var j = 0; j < tx.rct_signatures.p.MGs[i].ss.length; j++) {
				buf3 += tx.rct_signatures.p.MGs[i].ss[j][0];
				buf3 += tx.rct_signatures.p.MGs[i].ss[j][1];
			}
			buf3 += tx.rct_signatures.p.MGs[i].cc;
		}
		hashes += this.cn_fast_hash(buf3);
		buf += buf3;
		var hash = this.cn_fast_hash(hashes);
		return {
			raw: buf,
			hash: hash,
		};
	};

	this.serialize_rct_base = function(rv) {
		var buf = "";
		buf += this.encode_varint(rv.type);
		buf += this.encode_varint(rv.txnFee);
		if (rv.type === 2) {
			for (var i = 0; i < rv.pseudoOuts.length; i++) {
				buf += rv.pseudoOuts[i];
			}
		}
		if (rv.ecdhInfo.length !== rv.outPk.length) {
			throw "mismatched outPk/ecdhInfo!";
		}
		for (i = 0; i < rv.ecdhInfo.length; i++) {
			buf += rv.ecdhInfo[i].mask;
			buf += rv.ecdhInfo[i].amount;
		}
		for (i = 0; i < rv.outPk.length; i++) {
			buf += rv.outPk[i];
		}
		return buf;
	};

	this.generate_ring_signature = function(
		prefix_hash,
		k_image,
		keys,
		sec,
		real_index,
	) {
		if (k_image.length !== STRUCT_SIZES.KEY_IMAGE * 2) {
			throw "invalid key image length";
		}
		if (sec.length !== KEY_SIZE * 2) {
			throw "Invalid secret key length";
		}
		if (
			prefix_hash.length !== HASH_SIZE * 2 ||
			!this.valid_hex(prefix_hash)
		) {
			throw "Invalid prefix hash";
		}
		if (real_index >= keys.length || real_index < 0) {
			throw "real_index is invalid";
		}
		var _ge_tobytes = CNCrypto.cwrap("ge_tobytes", "void", [
			"number",
			"number",
		]);
		var _ge_p3_tobytes = CNCrypto.cwrap("ge_p3_tobytes", "void", [
			"number",
			"number",
		]);
		var _ge_scalarmult_base = CNCrypto.cwrap("ge_scalarmult_base", "void", [
			"number",
			"number",
		]);
		var _ge_scalarmult = CNCrypto.cwrap("ge_scalarmult", "void", [
			"number",
			"number",
			"number",
		]);
		var _sc_add = CNCrypto.cwrap("sc_add", "void", [
			"number",
			"number",
			"number",
		]);
		var _sc_sub = CNCrypto.cwrap("sc_sub", "void", [
			"number",
			"number",
			"number",
		]);
		var _sc_mulsub = CNCrypto.cwrap("sc_mulsub", "void", [
			"number",
			"number",
			"number",
			"number",
		]);
		var _sc_0 = CNCrypto.cwrap("sc_0", "void", ["number"]);
		var _ge_double_scalarmult_base_vartime = CNCrypto.cwrap(
			"ge_double_scalarmult_base_vartime",
			"void",
			["number", "number", "number", "number"],
		);
		var _ge_double_scalarmult_precomp_vartime = CNCrypto.cwrap(
			"ge_double_scalarmult_precomp_vartime",
			"void",
			["number", "number", "number", "number", "number"],
		);
		var _ge_frombytes_vartime = CNCrypto.cwrap(
			"ge_frombytes_vartime",
			"number",
			["number", "number"],
		);
		var _ge_dsm_precomp = CNCrypto.cwrap("ge_dsm_precomp", "void", [
			"number",
			"number",
		]);

		var buf_size = STRUCT_SIZES.EC_POINT * 2 * keys.length;
		var buf_m = CNCrypto._malloc(buf_size);
		var sig_size = STRUCT_SIZES.SIGNATURE * keys.length;
		var sig_m = CNCrypto._malloc(sig_size);

		// Struct pointer helper functions
		function buf_a(i) {
			return buf_m + STRUCT_SIZES.EC_POINT * (2 * i);
		}
		function buf_b(i) {
			return buf_m + STRUCT_SIZES.EC_POINT * (2 * i + 1);
		}
		function sig_c(i) {
			return sig_m + STRUCT_SIZES.EC_SCALAR * (2 * i);
		}
		function sig_r(i) {
			return sig_m + STRUCT_SIZES.EC_SCALAR * (2 * i + 1);
		}
		var image_m = CNCrypto._malloc(STRUCT_SIZES.KEY_IMAGE);
		CNCrypto.HEAPU8.set(hextobin(k_image), image_m);
		var i;
		var image_unp_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var image_pre_m = CNCrypto._malloc(STRUCT_SIZES.GE_DSMP);
		var sum_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var k_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var h_m = CNCrypto._malloc(STRUCT_SIZES.EC_SCALAR);
		var tmp2_m = CNCrypto._malloc(STRUCT_SIZES.GE_P2);
		var tmp3_m = CNCrypto._malloc(STRUCT_SIZES.GE_P3);
		var pub_m = CNCrypto._malloc(KEY_SIZE);
		var sec_m = CNCrypto._malloc(KEY_SIZE);
		CNCrypto.HEAPU8.set(hextobin(sec), sec_m);
		if (_ge_frombytes_vartime(image_unp_m, image_m) != 0) {
			throw "failed to call ge_frombytes_vartime";
		}
		_ge_dsm_precomp(image_pre_m, image_unp_m);
		_sc_0(sum_m);
		for (i = 0; i < keys.length; i++) {
			if (i === real_index) {
				// Real key
				var rand = this.random_scalar();
				CNCrypto.HEAPU8.set(hextobin(rand), k_m);
				_ge_scalarmult_base(tmp3_m, k_m);
				_ge_p3_tobytes(buf_a(i), tmp3_m);
				var ec = this.hash_to_ec(keys[i]);
				CNCrypto.HEAPU8.set(hextobin(ec), tmp3_m);
				_ge_scalarmult(tmp2_m, k_m, tmp3_m);
				_ge_tobytes(buf_b(i), tmp2_m);
			} else {
				CNCrypto.HEAPU8.set(hextobin(this.random_scalar()), sig_c(i));
				CNCrypto.HEAPU8.set(hextobin(this.random_scalar()), sig_r(i));
				CNCrypto.HEAPU8.set(hextobin(keys[i]), pub_m);
				if (
					CNCrypto.ccall(
						"ge_frombytes_vartime",
						"void",
						["number", "number"],
						[tmp3_m, pub_m],
					) !== 0
				) {
					throw "Failed to call ge_frombytes_vartime";
				}
				_ge_double_scalarmult_base_vartime(
					tmp2_m,
					sig_c(i),
					tmp3_m,
					sig_r(i),
				);
				_ge_tobytes(buf_a(i), tmp2_m);
				var ec = this.hash_to_ec(keys[i]);
				CNCrypto.HEAPU8.set(hextobin(ec), tmp3_m);
				_ge_double_scalarmult_precomp_vartime(
					tmp2_m,
					sig_r(i),
					tmp3_m,
					sig_c(i),
					image_pre_m,
				);
				_ge_tobytes(buf_b(i), tmp2_m);
				_sc_add(sum_m, sum_m, sig_c(i));
			}
		}
		var buf_bin = CNCrypto.HEAPU8.subarray(buf_m, buf_m + buf_size);
		var scalar = this.hash_to_scalar(prefix_hash + bintohex(buf_bin));
		CNCrypto.HEAPU8.set(hextobin(scalar), h_m);
		_sc_sub(sig_c(real_index), h_m, sum_m);
		_sc_mulsub(sig_r(real_index), sig_c(real_index), sec_m, k_m);
		var sig_data = bintohex(
			CNCrypto.HEAPU8.subarray(sig_m, sig_m + sig_size),
		);
		var sigs = [];
		for (var k = 0; k < keys.length; k++) {
			sigs.push(
				sig_data.slice(
					STRUCT_SIZES.SIGNATURE * 2 * k,
					STRUCT_SIZES.SIGNATURE * 2 * (k + 1),
				),
			);
		}
		CNCrypto._free(image_m);
		CNCrypto._free(image_unp_m);
		CNCrypto._free(image_pre_m);
		CNCrypto._free(sum_m);
		CNCrypto._free(k_m);
		CNCrypto._free(h_m);
		CNCrypto._free(tmp2_m);
		CNCrypto._free(tmp3_m);
		CNCrypto._free(buf_m);
		CNCrypto._free(sig_m);
		CNCrypto._free(pub_m);
		CNCrypto._free(sec_m);
		return sigs;
	};

	this.construct_tx = function(
		keys,
		sources,
		dsts,
		fee_amount,
		payment_id,
		pid_encrypt,
		realDestViewKey,
		unlock_time,
		rct,
		nettype,
	) {
		//we move payment ID stuff here, because we need txkey to encrypt
		var txkey = this.random_keypair();
		console.log(txkey);
		var extra = "";
		if (payment_id) {
			if (pid_encrypt && payment_id.length !== INTEGRATED_ID_SIZE * 2) {
				throw "payment ID must be " +
					INTEGRATED_ID_SIZE +
					" bytes to be encrypted!";
			}
			console.log("Adding payment id: " + payment_id);
			if (pid_encrypt) {
				//get the derivation from our passed viewkey, then hash that + tail to get encryption key
				var pid_key = this.cn_fast_hash(
					this.generate_key_derivation(realDestViewKey, txkey.sec) +
						ENCRYPTED_PAYMENT_ID_TAIL.toString(16),
				).slice(0, INTEGRATED_ID_SIZE * 2);
				console.log("Txkeys:", txkey, "Payment ID key:", pid_key);
				payment_id = this.hex_xor(payment_id, pid_key);
			}
			var nonce = this.get_payment_id_nonce(payment_id, pid_encrypt);
			console.log("Extra nonce: " + nonce);
			extra = this.add_nonce_to_extra(extra, nonce);
		}
		var tx = {
			unlock_time: unlock_time,
			version: rct ? CURRENT_TX_VERSION : OLD_TX_VERSION,
			extra: extra,
			vin: [],
			vout: [],
		};
		if (rct) {
			tx.rct_signatures = {};
		} else {
			tx.signatures = [];
		}

		var in_contexts = [];
		var inputs_money = JSBigInt.ZERO;
		var i, j;
		console.log("Sources: ");
		//run the for loop twice to sort ins by key image
		//first generate key image and other construction data to sort it all in one go
		for (i = 0; i < sources.length; i++) {
			console.log(i + ": " + this.formatMoneyFull(sources[i].amount));
			if (sources[i].real_out >= sources[i].outputs.length) {
				throw "real index >= outputs.length";
			}
			var res = this.generate_key_image_helper_rct(
				keys,
				sources[i].real_out_tx_key,
				sources[i].real_out_in_tx,
				sources[i].mask,
			); //mask will be undefined for non-rct
			if (
				res.in_ephemeral.pub !==
				sources[i].outputs[sources[i].real_out].key
			) {
				throw "in_ephemeral.pub != source.real_out.key";
			}
			sources[i].key_image = res.image;
			sources[i].in_ephemeral = res.in_ephemeral;
		}
		//sort ins
		sources.sort(function(a, b) {
			return (
				JSBigInt.parse(a.key_image, 16).compare(
					JSBigInt.parse(b.key_image, 16),
				) * -1
			);
		});
		//copy the sorted sources data to tx
		for (i = 0; i < sources.length; i++) {
			inputs_money = inputs_money.add(sources[i].amount);
			in_contexts.push(sources[i].in_ephemeral);
			var input_to_key = {};
			input_to_key.type = "input_to_key";
			input_to_key.amount = sources[i].amount;
			input_to_key.k_image = sources[i].key_image;
			input_to_key.key_offsets = [];
			for (j = 0; j < sources[i].outputs.length; ++j) {
				input_to_key.key_offsets.push(sources[i].outputs[j].index);
			}
			input_to_key.key_offsets = this.abs_to_rel_offsets(
				input_to_key.key_offsets,
			);
			tx.vin.push(input_to_key);
		}
		var outputs_money = JSBigInt.ZERO;
		var out_index = 0;
		var amountKeys = []; //rct only
		for (i = 0; i < dsts.length; ++i) {
			if (new JSBigInt(dsts[i].amount).compare(0) < 0) {
				throw "dst.amount < 0"; //amount can be zero if no change
			}
			dsts[i].keys = this.decode_address(dsts[i].address, nettype);

			// R = rD for subaddresses
			if (this.is_subaddress(dsts[i].address, nettype)) {
				if (typeof payment_id !== "undefined" && payment_id) {
					// this could stand to be placed earlier in the function but we save repeating a little algo time this way
					throw "Payment ID must not be supplied when sending to a subaddress";
				}
				txkey.pub = this.ge_scalarmult(dsts[i].keys.spend, txkey.sec);
			}

			var out_derivation;

			// send change to ourselves
			if (dsts[i].keys.view == keys.view.pub) {
				out_derivation = this.generate_key_derivation(
					txkey.pub,
					keys.view.sec,
				);
			} else {
				out_derivation = this.generate_key_derivation(
					dsts[i].keys.view,
					txkey.sec,
				);
			}

			if (rct) {
				amountKeys.push(
					this.derivation_to_scalar(out_derivation, out_index),
				);
			}
			var out_ephemeral_pub = this.derive_public_key(
				out_derivation,
				out_index,
				dsts[i].keys.spend,
			);
			var out = {
				amount: dsts[i].amount.toString(),
			};
			// txout_to_key
			out.target = {
				type: "txout_to_key",
				key: out_ephemeral_pub,
			};
			tx.vout.push(out);
			++out_index;
			outputs_money = outputs_money.add(dsts[i].amount);
		}

		// add pub key to extra after we know whether to use R = rG or R = rD
		tx.extra = this.add_pub_key_to_extra(tx.extra, txkey.pub);

		if (outputs_money.add(fee_amount).compare(inputs_money) > 0) {
			throw "outputs money (" +
				this.formatMoneyFull(outputs_money) +
				") + fee (" +
				this.formatMoneyFull(fee_amount) +
				") > inputs money (" +
				this.formatMoneyFull(inputs_money) +
				")";
		}
		if (!rct) {
			for (i = 0; i < sources.length; ++i) {
				var src_keys = [];
				for (j = 0; j < sources[i].outputs.length; ++j) {
					src_keys.push(sources[i].outputs[j].key);
				}
				var sigs = this.generate_ring_signature(
					this.get_tx_prefix_hash(tx),
					tx.vin[i].k_image,
					src_keys,
					in_contexts[i].sec,
					sources[i].real_out,
				);
				tx.signatures.push(sigs);
			}
		} else {
			//rct
			var txnFee = fee_amount;
			var keyimages = [];
			var inSk = [];
			var inAmounts = [];
			var mixRing = [];
			var indices = [];
			for (i = 0; i < tx.vin.length; i++) {
				keyimages.push(tx.vin[i].k_image);
				inSk.push({
					x: in_contexts[i].sec,
					a: in_contexts[i].mask,
				});
				inAmounts.push(tx.vin[i].amount);
				if (in_contexts[i].mask !== I) {
					//if input is rct (has a valid mask), 0 out amount
					tx.vin[i].amount = "0";
				}
				mixRing[i] = [];
				for (j = 0; j < sources[i].outputs.length; j++) {
					mixRing[i].push({
						dest: sources[i].outputs[j].key,
						mask: sources[i].outputs[j].commit,
					});
				}
				indices.push(sources[i].real_out);
			}
			var outAmounts = [];
			for (i = 0; i < tx.vout.length; i++) {
				outAmounts.push(tx.vout[i].amount);
				tx.vout[i].amount = "0"; //zero out all rct outputs
			}
			var tx_prefix_hash = this.get_tx_prefix_hash(tx);
			tx.rct_signatures = genRct(
				tx_prefix_hash,
				inSk,
				keyimages,
				/*destinations, */ inAmounts,
				outAmounts,
				mixRing,
				amountKeys,
				indices,
				txnFee,
			);
		}
		console.log(tx);
		return tx;
	};

	this.create_transaction = function(
		pub_keys,
		sec_keys,
		dsts,
		outputs,
		mix_outs,
		fake_outputs_count,
		fee_amount,
		payment_id,
		pid_encrypt,
		realDestViewKey,
		unlock_time,
		rct,
		nettype,
	) {
		unlock_time = unlock_time || 0;
		mix_outs = mix_outs || [];
		var i, j;
		if (dsts.length === 0) {
			throw "Destinations empty";
		}
		if (mix_outs.length !== outputs.length && fake_outputs_count !== 0) {
			throw "Wrong number of mix outs provided (" +
				outputs.length +
				" outputs, " +
				mix_outs.length +
				" mix outs)";
		}
		for (i = 0; i < mix_outs.length; i++) {
			if ((mix_outs[i].outputs || []).length < fake_outputs_count) {
				throw "Not enough outputs to mix with";
			}
		}
		var keys = {
			view: {
				pub: pub_keys.view,
				sec: sec_keys.view,
			},
			spend: {
				pub: pub_keys.spend,
				sec: sec_keys.spend,
			},
		};
		if (
			!this.valid_keys(
				keys.view.pub,
				keys.view.sec,
				keys.spend.pub,
				keys.spend.sec,
			)
		) {
			throw "Invalid secret keys!";
		}
		var needed_money = JSBigInt.ZERO;
		for (i = 0; i < dsts.length; ++i) {
			needed_money = needed_money.add(dsts[i].amount);
			if (needed_money.compare(UINT64_MAX) !== -1) {
				throw "Output overflow!";
			}
		}
		var found_money = JSBigInt.ZERO;
		var sources = [];
		console.log("Selected transfers: ", outputs);
		for (i = 0; i < outputs.length; ++i) {
			found_money = found_money.add(outputs[i].amount);
			if (found_money.compare(UINT64_MAX) !== -1) {
				throw "Input overflow!";
			}
			var src = {
				outputs: [],
			};
			src.amount = new JSBigInt(outputs[i].amount).toString();
			if (mix_outs.length !== 0) {
				// Sort fake outputs by global index
				mix_outs[i].outputs.sort(function(a, b) {
					return new JSBigInt(a.global_index).compare(b.global_index);
				});
				j = 0;
				while (
					src.outputs.length < fake_outputs_count &&
					j < mix_outs[i].outputs.length
				) {
					var out = mix_outs[i].outputs[j];
					if (out.global_index === outputs[i].global_index) {
						console.log("got mixin the same as output, skipping");
						j++;
						continue;
					}
					var oe = {};
					oe.index = out.global_index.toString();
					oe.key = out.public_key;
					if (rct) {
						if (out.rct) {
							oe.commit = out.rct.slice(0, 64); //add commitment from rct mix outs
						} else {
							if (outputs[i].rct) {
								throw "mix rct outs missing commit";
							}
							oe.commit = zeroCommit(d2s(src.amount)); //create identity-masked commitment for non-rct mix input
						}
					}
					src.outputs.push(oe);
					j++;
				}
			}
			var real_oe = {};
			real_oe.index = new JSBigInt(
				outputs[i].global_index || 0,
			).toString();
			real_oe.key = outputs[i].public_key;
			if (rct) {
				if (outputs[i].rct) {
					real_oe.commit = outputs[i].rct.slice(0, 64); //add commitment for real input
				} else {
					real_oe.commit = zeroCommit(d2s(src.amount)); //create identity-masked commitment for non-rct input
				}
			}
			var real_index = src.outputs.length;
			for (j = 0; j < src.outputs.length; j++) {
				if (
					new JSBigInt(real_oe.index).compare(src.outputs[j].index) <
					0
				) {
					real_index = j;
					break;
				}
			}
			// Add real_oe to outputs
			src.outputs.splice(real_index, 0, real_oe);
			src.real_out_tx_key = outputs[i].tx_pub_key;
			// Real output entry index
			src.real_out = real_index;
			src.real_out_in_tx = outputs[i].index;
			if (rct) {
				if (outputs[i].rct) {
					src.mask = outputs[i].rct.slice(64, 128); //encrypted
				} else {
					src.mask = null; //will be set by generate_key_image_helper_rct
				}
			}
			sources.push(src);
		}
		console.log("sources: ", sources);
		var change = {
			amount: JSBigInt.ZERO,
		};
		var cmp = needed_money.compare(found_money);
		if (cmp < 0) {
			change.amount = found_money.subtract(needed_money);
			if (change.amount.compare(fee_amount) !== 0) {
				throw "early fee calculation != later";
			}
		} else if (cmp > 0) {
			throw "Need more money than found! (have: " +
				cnUtil.formatMoney(found_money) +
				" need: " +
				cnUtil.formatMoney(needed_money) +
				")";
		}
		return this.construct_tx(
			keys,
			sources,
			dsts,
			fee_amount,
			payment_id,
			pid_encrypt,
			realDestViewKey,
			unlock_time,
			rct,
			nettype,
		);
	};

	this.estimateRctSize = function(inputs, mixin, outputs) {
		var size = 0;
		// tx prefix
		// first few bytes
		size += 1 + 6;
		size += inputs * (1 + 6 + (mixin + 1) * 3 + 32); // original C implementation is *2+32 but author advised to change 2 to 3 as key offsets are variable size and this constitutes a best guess
		// vout
		size += outputs * (6 + 32);
		// extra
		size += 40;
		// rct signatures
		// type
		size += 1;
		// rangeSigs
		size += (2 * 64 * 32 + 32 + 64 * 32) * outputs;
		// MGs
		size += inputs * (32 * (mixin + 1) + 32);
		// mixRing - not serialized, can be reconstructed
		/* size += 2 * 32 * (mixin+1) * inputs; */
		// pseudoOuts
		size += 32 * inputs;
		// ecdhInfo
		size += 2 * 32 * outputs;
		// outPk - only commitment is saved
		size += 32 * outputs;
		// txnFee
		size += 4;
		// const logStr = `estimated rct tx size for ${inputs} at mixin ${mixin} and ${outputs} : ${size}  (${((32 * inputs/*+1*/) + 2 * 32 * (mixin+1) * inputs + 32 * outputs)}) saved)`
		// console.log(logStr)

		return size;
	};

	function trimRight(str, char) {
		while (str[str.length - 1] == char) str = str.slice(0, -1);
		return str;
	}

	function padLeft(str, len, char) {
		while (str.length < len) {
			str = char + str;
		}
		return str;
	}

	this.printDsts = function(dsts) {
		for (var i = 0; i < dsts.length; i++) {
			console.log(
				dsts[i].address + ": " + this.formatMoneyFull(dsts[i].amount),
			);
		}
	};

	this.formatMoneyFull = function(units) {
		units = units.toString();
		var symbol = units[0] === "-" ? "-" : "";
		if (symbol === "-") {
			units = units.slice(1);
		}
		var decimal;
		if (units.length >= config.coinUnitPlaces) {
			decimal = units.substr(
				units.length - config.coinUnitPlaces,
				config.coinUnitPlaces,
			);
		} else {
			decimal = padLeft(units, config.coinUnitPlaces, "0");
		}
		return (
			symbol +
			(units.substr(0, units.length - config.coinUnitPlaces) || "0") +
			"." +
			decimal
		);
	};

	this.formatMoneyFullSymbol = function(units) {
		return this.formatMoneyFull(units) + " " + config.coinSymbol;
	};

	this.formatMoney = function(units) {
		var f = trimRight(this.formatMoneyFull(units), "0");
		if (f[f.length - 1] === ".") {
			return f.slice(0, f.length - 1);
		}
		return f;
	};

	this.formatMoneySymbol = function(units) {
		return this.formatMoney(units) + " " + config.coinSymbol;
	};

	this.parseMoney = function(str) {
		if (!str) return JSBigInt.ZERO;
		var negative = str[0] === "-";
		if (negative) {
			str = str.slice(1);
		}
		var decimalIndex = str.indexOf(".");
		if (decimalIndex == -1) {
			if (negative) {
				return JSBigInt.multiply(str, config.coinUnits).negate();
			}
			return JSBigInt.multiply(str, config.coinUnits);
		}
		if (decimalIndex + config.coinUnitPlaces + 1 < str.length) {
			str = str.substr(0, decimalIndex + config.coinUnitPlaces + 1);
		}
		if (negative) {
			return new JSBigInt(str.substr(0, decimalIndex))
				.exp10(config.coinUnitPlaces)
				.add(
					new JSBigInt(str.substr(decimalIndex + 1)).exp10(
						decimalIndex + config.coinUnitPlaces - str.length + 1,
					),
				).negate;
		}
		return new JSBigInt(str.substr(0, decimalIndex))
			.exp10(config.coinUnitPlaces)
			.add(
				new JSBigInt(str.substr(decimalIndex + 1)).exp10(
					decimalIndex + config.coinUnitPlaces - str.length + 1,
				),
			);
	};

	this.decompose_amount_into_digits = function(amount) {
		/*if (dust_threshold === undefined) {
			dust_threshold = config.dustThreshold;
		}*/
		amount = amount.toString();
		var ret = [];
		while (amount.length > 0) {
			//split all the way down since v2 fork
			/*var remaining = new JSBigInt(amount);
			if (remaining.compare(config.dustThreshold) <= 0) {
				if (remaining.compare(0) > 0) {
					ret.push(remaining);
				}
				break;
			}*/
			//check so we don't create 0s
			if (amount[0] !== "0") {
				var digit = amount[0];
				while (digit.length < amount.length) {
					digit += "0";
				}
				ret.push(new JSBigInt(digit));
			}
			amount = amount.slice(1);
		}
		return ret;
	};

	this.decompose_tx_destinations = function(dsts, rct) {
		var out = [];
		if (rct) {
			for (var i = 0; i < dsts.length; i++) {
				out.push({
					address: dsts[i].address,
					amount: dsts[i].amount,
				});
			}
		} else {
			for (var i = 0; i < dsts.length; i++) {
				var digits = this.decompose_amount_into_digits(dsts[i].amount);
				for (var j = 0; j < digits.length; j++) {
					if (digits[j].compare(0) > 0) {
						out.push({
							address: dsts[i].address,
							amount: digits[j],
						});
					}
				}
			}
		}
		return out.sort(function(a, b) {
			return a["amount"] - b["amount"];
		});
	};

	this.is_tx_unlocked = function(unlock_time, blockchain_height) {
		if (!config.maxBlockNumber) {
			throw "Max block number is not set in config!";
		}
		if (unlock_time < config.maxBlockNumber) {
			// unlock time is block height
			return blockchain_height >= unlock_time;
		} else {
			// unlock time is timestamp
			var current_time = Math.round(new Date().getTime() / 1000);
			return current_time >= unlock_time;
		}
	};

	this.tx_locked_reason = function(unlock_time, blockchain_height) {
		if (unlock_time < config.maxBlockNumber) {
			// unlock time is block height
			var numBlocks = unlock_time - blockchain_height;
			if (numBlocks <= 0) {
				return "Transaction is unlocked";
			}
			var unlock_prediction = moment().add(
				numBlocks * config.avgBlockTime,
				"seconds",
			);
			return (
				"Will be unlocked in " +
				numBlocks +
				" blocks, ~" +
				unlock_prediction.fromNow(true) +
				", " +
				unlock_prediction.calendar() +
				""
			);
		} else {
			// unlock time is timestamp
			var current_time = Math.round(new Date().getTime() / 1000);
			var time_difference = unlock_time - current_time;
			if (time_difference <= 0) {
				return "Transaction is unlocked";
			}
			var unlock_moment = moment(unlock_time * 1000);
			return (
				"Will be unlocked " +
				unlock_moment.fromNow() +
				", " +
				unlock_moment.calendar()
			);
		}
	};

	function assert(stmt, val) {
		if (!stmt) {
			throw "assert failed" + (val !== undefined ? ": " + val : "");
		}
	}

	return this;
};
exports.cnUtil = cnUtil;