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copied!<p><strong>Edit</strong> (now that I've done the math)</p> <p>There are around 6*10^36 possible combinations you'll need to iterate through - the largest <code>long</code> value is about 9*10^18 - a <em>much</em> smaller number. </p> <p>That being said, say you find an optimized way to iterate over the combinations where you can generate and compare a trillion (10^12) combinations per second (<em>much</em> faster than your average developer's machine), and you can parallelize it across a million machines - that would be (60*60*24*365*10^12)*10^6 per year, or about 3*10^25 combinations checked per year.</p> <p>At that blazing speed, <strong>it would still take ~190 billion years to go over all combinations.</strong> </p> <p>I strongly urge you to investigate another alternative for achieving your goal instead of trying every single key.</p> <p>Now (back to my original answer), if you had a reasonably sized subset of keys you wanted to iterate over, I could imagine doing something like this with a straight up number loop that just converted the number to a modified base-26 for the key.</p> <p>Some pseudo-code:</p> <pre><code>public void runAlgorithm () { for (int i=startKey; i<endKey; i++) { String key = toBase26(i); testKey(key); } } </code></pre> <p>Use something like <a href="http://en.wikipedia.org/wiki/Hexavigesimal" rel="nofollow">this hexavigesimal converter from wikipedia</a> for the impl of <code>toBase26</code> (copied below):</p> <pre><code>public static String toBase26(int number){ number = Math.abs(number); String converted = ""; // Repeatedly divide the number by 26 and convert the // remainder into the appropriate letter. do { int remainder = number % 26; converted = (char)(remainder + 'A') + converted; number = (number - remainder) / 26; } while (number > 0); return converted; } </code></pre>

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