user62790: I'm not interested in bitcoin mining , I just want to generate  sha256 hash of all possible input string of 64 characters length , can I use bitcoin mining hardware just to generate just sha256 hash for my personal use? 

user61332: Most bitcoin ASICs take as input a SHA256 chaining value and a 480-bit block, and they try every possible 32-bit suffix to check if SHA256(SHA256(block + suffix)) begins with sufficiently many zero bits.
So, it won't be easy to do what you want to do (crack a password?).
There are use cases where this limited functionnality is sufficient though, see the 3SUM-pool for instance (disclaimer : it's mine).

62790: <p>I'm not interested in bitcoin mining , I just want to generate  sha256 hash of all possible input string of 64 characters length , can I use bitcoin mining hardware just to generate just sha256 hash for my personal use? </p>
 61332: <p>Most bitcoin ASICs take as input a SHA256 chaining value and a 480-bit block, and they try every possible 32-bit suffix to check if SHA256(SHA256(block + suffix)) begins with sufficiently many zero bits.</p>

<p>So, it won't be easy to do what you want to do (crack a password?).</p>

<p>There are use cases where this limited functionnality is sufficient though, see the <a href="http://cristal.univ-lille.fr/3sum-pool" rel="nofollow noreferrer">3SUM-pool</a> for instance (disclaimer : it's mine).</p>
