Merge pull request #11 from cryptochangements34/derive-subaddress-public-key

add derive_subaddress_public_key function + basic cryptonote tests

cryptonote_utils/cryptonote_utils.js

@@ -661,6 +661,16 @@ var cnUtil = function(currencyConfig)
 		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)) {

tests/cryptonote_utils.js

@@ -0,0 +1,59 @@
+"use strict"
+const mymonero = require('mymonero-core-js');
+const assert = require('assert');
+
+var public_key = "904e49462268d771cc1649084c35aa1296bfb214880fe2e7f373620a3e2ba597";
+var private_key = "52aa4c69b93b780885c9d7f51e6fd5795904962c61a2e07437e130784846f70d";
+
+describe('cryptonote_utils tests', function() {
+	
+	it('is valid hex', function() {
+		var valid = mymonero.monero_utils.valid_hex(private_key);
+		assert.strictEqual(valid, true);
+	});
+	
+	it('fast hash / keccak-256', function() {
+		var hash = mymonero.monero_utils.cn_fast_hash(private_key , private_key.length);
+		assert.equal(hash, "64997ff54f0d82ee87d51e971a0329d4315481eaeb4ad2403c65d5843480c414");
+	});
+	
+	it('generate key derivation', function() {
+		var derivation = mymonero.monero_utils.generate_key_derivation(public_key, private_key);
+		assert.equal(derivation, "591c749f1868c58f37ec3d2a9d2f08e7f98417ac4f8131e3a57c1fd71273ad00");
+	});
+	
+	it('decode mainnet primary address', function() {
+		var decoded = mymonero.monero_utils.decode_address("49qwWM9y7j1fvaBK684Y5sMbN8MZ3XwDLcSaqcKwjh5W9kn9qFigPBNBwzdq6TCAm2gKxQWrdZuEZQBMjQodi9cNRHuCbTr");
+		var expected = { spend: "d8f1e81ecbe25ce8b596d426fb02fe7b1d4bb8d14c06b3d3e371a60eeea99534", view: "576f0e61e250d941746ed147f602b5eb1ea250ca385b028a935e166e18f74bd7" }
+		assert.deepEqual(decoded, expected);
+	});
+	
+	it('decode mainnet integrated address', function() {
+		var decoded = mymonero.monero_utils.decode_address("4KYcX9yTizXfvaBK684Y5sMbN8MZ3XwDLcSaqcKwjh5W9kn9qFigPBNBwzdq6TCAm2gKxQWrdZuEZQBMjQodi9cNd3mZpgrjXBKMx9ee7c");
+		var expected = { spend: "d8f1e81ecbe25ce8b596d426fb02fe7b1d4bb8d14c06b3d3e371a60eeea99534", view: "576f0e61e250d941746ed147f602b5eb1ea250ca385b028a935e166e18f74bd7", intPaymentId: "83eab71fbee84eb9" }
+		assert.deepEqual(decoded, expected);
+	});
+	
+	it('hash_to_scalar', function() {
+		var scalar = mymonero.monero_utils.hash_to_scalar(private_key);
+		assert.equal(scalar, "77c5899835aa6f96b13827f43b094abf315481eaeb4ad2403c65d5843480c404");
+	});
+	
+	it('derivation_to_scalar', function() {
+		var derivation = mymonero.monero_utils.generate_key_derivation(public_key, private_key);
+		var scalar = mymonero.monero_utils.derivation_to_scalar(derivation, 1);
+		assert.equal(scalar, "201ce3c258e09eeb6132ec266d24ee1ca957828f384ce052d5bc217c2c55160d");
+	});
+	
+	it('derive public key', function() {
+		var derivation = mymonero.monero_utils.generate_key_derivation(public_key, private_key);
+		var output_key = mymonero.monero_utils.derive_public_key(derivation, 1, public_key);
+		assert.equal(output_key, "da26518ddb54cde24ccfc59f36df13bbe9bdfcb4ef1b223d9ab7bef0a50c8be3");
+	});
+	
+	it('derive subaddress public key', function() {
+		var derivation = mymonero.monero_utils.generate_key_derivation(public_key, private_key);
+		var subaddress_public_key = mymonero.monero_utils.derive_subaddress_public_key(public_key, derivation, 1);
+		assert.equal(subaddress_public_key, "dfc9e4a0039e913204c1c0f78e954a7ec7ce291d8ffe88265632f0da9d8de1be")
+	});
+});