user38775: I am running this command
$ vanitygen64.exe 1abcdefg
Difficulty: 778316249440
[125.17 Kkey/s][total 39015067414][Prob 4.9%][50% in 46.3d]


What is it mean Difficulty? I understand that higher takes more time, but what is the scale, why it is different from total? Why alphabet is more difficult than only digits vanitygen1234567`?
What is it mean 50% in 46 days, why it not tell me 100%. After 46 days, how much percent will be that it will complete in the next 46 days? If it is same reasons  as in Half-Life in nuclear physics I understand it.
The big question. What it is Prob 4.9%? Prob of what?


user31470: 
Difficulty tells you how likely it is that vanitygen will be able to find the address pattern you're looking for on the next guess. A value of 2n is twice as difficult (half as likely) than a value of n.
Because the process is completely random, it's impossible to give you a '100%' ETA. We can only estimate that, on average, you will find your key before some time period half the time (hence why 50% is used). Note that it re-adjusts the value to 75% once it hits that 50% mark (and re-adjusts again after hitting 75%, until the key is eventually found).
That is the likelihood that you would have found your key by now, from the time when you started generating your key.


38775: <p>I am running this command</p>

<pre><code>$ vanitygen64.exe 1abcdefg
Difficulty: 778316249440
[125.17 Kkey/s][total 39015067414][Prob 4.9%][50% in 46.3d]
</code></pre>

<ol>
<li><p>What is it mean <code>Difficulty</code>? I understand that higher takes more time, but what is the scale, why it is different from total? Why alphabet is more difficult than only digits <code>vanitygen</code>1234567`?</p></li>
<li><p>What is it mean <code>50%</code> in 46 days, why it not tell me 100%. After 46 days, how much percent will be that it will complete in the next 46 days? If it is same reasons  as in <a href="https://en.wikipedia.org/wiki/Half-life" rel="nofollow">Half-Life in nuclear physics</a> I understand it.</p></li>
<li><p>The big question. What it is <strong><code>Prob 4.9%</code></strong>? <code>Prob</code> of what?</p></li>
</ol>
 31470: <ol>
<li>Difficulty tells you how likely it is that vanitygen will be able to find the address pattern you're looking for on the next guess. A value of 2n is twice as difficult (half as likely) than a value of n.</li>
<li>Because the process is completely random, it's impossible to give you a '100%' ETA. We can only estimate that, on average, you will find your key before some time period <em>half</em> the time (hence why 50% is used). Note that it re-adjusts the value to 75% once it hits that 50% mark (and re-adjusts again after hitting 75%, until the key is eventually found).</li>
<li>That is the likelihood that you would have found your key by <em>now</em>, from the time when you started generating your key.</li>
</ol>
