user12062: I want to generate very long vanity addresses, with the relaxed constraint that I don't need the corresponding private key, they only need to be valid Bitcoin addresses. How would I do this?
Example:
Input Prefix: 1XXXXXXXXXXXXXXXXXXXX
Output: 1XXXXXXXXXXXXXXXXXXXXUW9j3f3


user13751: You can do this manually using the hex/base58check converter (such as the converter on brainwallet.org)

Remove the starting 1 and convert from base58 XXXXXXXXXXXXXXXXXXXXXXXXXXX to hex: 25c7415deb828c49ccb799c452ae17589bca1af2 (make sure result is 24 bytes)
Remove last 4 bytes to get a 20-byte hash:
25c7415deb828c49ccb799c452ae17589bca1af2 -> 25c7415deb828c49ccb799c452ae1758
Convert from hex 25c7415deb828c49ccb799c452ae1758 to base58check: 1XXXXXXXXXXXXXXXXXXXXXYDgWVE

Final result is valid 1XXXXXXXXXXXXXXXXXXXXXYDgWVE

12062: <p>I want to generate very long vanity addresses, with the relaxed constraint that I don't need the corresponding private key, they only need to be valid Bitcoin addresses. How would I do this?</p>

<p>Example:</p>

<pre><code>Input Prefix: 1XXXXXXXXXXXXXXXXXXXX
Output: 1XXXXXXXXXXXXXXXXXXXXUW9j3f3
</code></pre>
 13751: <p>You can do this manually using the hex/base58check converter (such as the converter on brainwallet.org)</p>

<ol>
<li><p>Remove the starting <code>1</code> and convert from base58 <code>XXXXXXXXXXXXXXXXXXXXXXXXXXX</code> to hex: <code>25c7415deb828c49ccb799c452ae17589bca1af2</code> (make sure result is 24 bytes)</p></li>
<li><p>Remove last 4 bytes to get a 20-byte hash:
<code>25c7415deb828c49ccb799c452ae17589bca1af2</code> -> <code>25c7415deb828c49ccb799c452ae1758</code></p></li>
<li><p>Convert from hex <code>25c7415deb828c49ccb799c452ae1758</code> to base58check: <code>1XXXXXXXXXXXXXXXXXXXXXYDgWVE</code></p></li>
</ol>

<p>Final result is valid <code>1XXXXXXXXXXXXXXXXXXXXXYDgWVE</code></p>
