Issue #8 - Added 'betterrand' key generator which bases the key around the current time rather than a series of random values

lib/key_generators/betterrand.js

@@ -0,0 +1,53 @@
+/*
+	The current timestamp is sha1 hashed, then that hash value is converted
+	into a number system represented by a 'legible' alphabet.
+
+	This provides several enhancements over the default random keygen.
+		1) Keys are unlikely to collide due to using timestamp as seed
+		2) Keys will display more entropy due to sha1-hashing
+		3) Similar-looking letters have been removed from alphabet
+*/
+
+var crypto = require('crypto');
+
+// the alphabet is separated this way so when we convert hex to this system,
+// we can have some manner of style, like upper case, followed by 2 lower case, etc.
+var code = ['ABCDEFGHJKMNPRSTWXYZ',
+			'abcdefhkmnprstwxyz',
+			/*'abcdefhkmnprstwxyz',
+			'0123456789'*/];
+
+function sha1(str) {
+ 	var hash = crypto.createHash('sha1');
+ 	hash.update(str);
+ 	return hash.digest('hex');
+}
+
+function convertNumberToLegible(n) {
+	var legible = '';
+	var codeIndex = 0;
+	var alphabet = code[codeIndex];
+	while (n > 0) {
+		var c = n % alphabet.length;
+		n = Math.floor(n / alphabet.length);
+		legible += alphabet.charAt(c);
+		codeIndex = (codeIndex+1) % code.length;
+		alphabet = code[codeIndex];
+	}
+	return legible;
+}
+
+function createKey(keyLength) {
+	// process.hrtime() gives more precision (nanoseconds?) than new Date().getTime() (milliseconds)
+	var time = process.hrtime().join('');
+	var sha1Hex= sha1(time).substring(0, 8);
+	var key = convertNumberToLegible(parseInt(sha1Hex, 16));
+	if (key.length > keyLength) {
+		return key.substring(0, keyLength);
+	}
+	return key;
+};
+
+var UniqueRandomKeyGenerator = function() {};
+UniqueRandomKeyGenerator.prototype.createKey = createKey;
+module.exports = UniqueRandomKeyGenerator;