<story><title>How easy is it in 2022 to find a SHA1 collision?</title><url>https://crypto.stackexchange.com/questions/99767/how-easy-is-it-in-2022-to-find-a-sha1-collision</url></story><parent_chain><item><author>dijit</author><text>This was fun, but my gut reaction to the title was “it doesn’t have to be easy, just possible” and that holds. Unless, I guess, you want to collide a sha1 for some reason.&lt;p&gt;I found the AWS vs GPU cost comparison to be fun. 10x the cost of the hardware to run the collisions in the same time window. Crazy.</text></item></parent_chain><comment><author>PragmaticPulp</author><text>&amp;gt; I found the AWS vs GPU cost comparison to be fun. 10x the cost of the hardware to run the collisions in the same time window. Crazy.&lt;p&gt;The real benefit of the AWS solution is that you could rent a large number of AWS nodes and run the calculations to completion right now if you wanted to. As in, literally tonight. And you wouldn’t have to source the hardware, assemble machines, install software, power it all, cool it, figure out all of the power complexities and so on.</text></comment>
<story><title>How easy is it in 2022 to find a SHA1 collision?</title><url>https://crypto.stackexchange.com/questions/99767/how-easy-is-it-in-2022-to-find-a-sha1-collision</url></story><parent_chain><item><author>dijit</author><text>This was fun, but my gut reaction to the title was “it doesn’t have to be easy, just possible” and that holds. Unless, I guess, you want to collide a sha1 for some reason.&lt;p&gt;I found the AWS vs GPU cost comparison to be fun. 10x the cost of the hardware to run the collisions in the same time window. Crazy.</text></item></parent_chain><comment><author>rco8786</author><text>Collisions are possible in any hashing algo. You’re taking infinite inputs and mapping them to finite number of outputs. There are literal infinite collisions in any hashing function.</text></comment>