		@@ -5,2 +5,8 @@ var Crypto = require('crypto');

		/**
		* Verifies a signature using the Steam "System" public key.
		* @param {Buffer} data
		* @param {Buffer} signature
		* @param {string} algorithm
		*/
		exports.verifySignature = function(data, signature, algorithm) {
		@@ -13,5 +19,10 @@ var verify = Crypto.createVerify(algorithm \|\| "RSA-SHA1");

		exports.generateSessionKey = function() {
		/**
		* Generate a 32-byte symmetric session key and encrypt it with Steam's public "System" key.
		* @param {Buffer} [nonce] - If provided, will be appended to the session key when encrypting
		* @returns {{plain: Buffer, encrypted: Buffer}}
		*/
		exports.generateSessionKey = function(nonce) {
		var sessionKey = Crypto.randomBytes(32);
		var cryptedSessionKey = Crypto.publicEncrypt(g_PubkeySystem, sessionKey);
		var cryptedSessionKey = Crypto.publicEncrypt(g_PubkeySystem, Buffer.concat([sessionKey, nonce \|\| new Buffer(0)]));
		return {
		@@ -23,23 +34,66 @@ plain: sessionKey,

		exports.symmetricEncrypt = function(input, key) {
		var iv = Crypto.randomBytes(16);
		/**
		* AES-encrypt some data with a symmetric key.
		* @param {Buffer} input
		* @param {Buffer} key
		* @param {Buffer} [iv] - If not provided, one will be generated randomly
		* @returns {Buffer}
		*/
		exports.symmetricEncrypt = function(input, key, iv) {
		iv = iv \|\| Crypto.randomBytes(16);
		var aesIv = Crypto.createCipheriv('aes-256-ecb', key, '');
		aesIv.setAutoPadding(false);
		aesIv.end(iv);


		var aesData = Crypto.createCipheriv('aes-256-cbc', key, iv);
		aesData.end(input);


		return Buffer.concat([aesIv.read(), aesData.read()]);
		};

		exports.symmetricDecrypt = function(input, key) {
		/**
		* AES-encrypt some data with a symmetric key, and add an HMAC.
		* @param {Buffer} input
		* @param {Buffer} key
		*/
		exports.symmetricEncryptWithHmacIv = function(input, key) {
		// IV is HMAC-SHA1(Random(3) + Plaintext) + Random(3). (Same random values for both)
		var random = Crypto.randomBytes(3);
		var hmac = Crypto.createHmac("sha1", key.slice(0, 16)); // we only want the first 16 bytes of the key for the hmac
		hmac.update(random);
		hmac.update(input);

		return exports.symmetricEncrypt(input, key, Buffer.concat([hmac.digest().slice(0, 16 - random.length), random])); // the resulting IV must be 16 bytes long, so truncate the hmac to make room for the random
		};

		/**
		* AES-decrypt some data with a symmetric key, and optionally check an HMAC.
		* @param {Buffer} input
		* @param {Buffer} key
		* @param {boolean} [checkHmac=false] - Does this data contain an HMAC for us to check?
		* @returns {*}
		*/
		exports.symmetricDecrypt = function(input, key, checkHmac) {
		var aesIv = Crypto.createDecipheriv('aes-256-ecb', key, '');
		aesIv.setAutoPadding(false);
		aesIv.end(input.slice(0, 16));

		var aesData = Crypto.createDecipheriv('aes-256-cbc', key, aesIv.read());
		var iv = aesIv.read();

		var aesData = Crypto.createDecipheriv('aes-256-cbc', key, iv);
		aesData.end(input.slice(16));

		return aesData.read();
		var plaintext = aesData.read();

		if (checkHmac) {
		// The last 3 bytes of the IV are a random value, and the remainder are a partial HMAC
		var remotePartialHmac = iv.slice(0, iv.length - 3);
		var random = iv.slice(iv.length - 3, iv.length);
		var hmac = Crypto.createHmac("sha1", key.slice(0, 16));
		hmac.update(random);
		hmac.update(plaintext);
		if (!remotePartialHmac.equals(hmac.digest().slice(0, remotePartialHmac.length))) {
		throw new Error("Received invalid HMAC from remote host.");
		}
		}

		return plaintext;
		};

package.json

		{
		"name": "@doctormckay/steam-crypto",
		"version": "1.0.0",
		"version": "1.1.0",
		"description": "Node.js implementation of Valve's crypto",
		@@ -5,0 +5,0 @@ "repository": {

@doctormckay/steam-crypto - npm Package Compare versions

New alerts

Fixed alerts

Improved metrics