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

This commit is contained in:
neandrake 2014-08-29 23:17:11 -04:00
parent 6c31389327
commit 8b112cc257

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@ -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;