Transaction

j"1LAnZuoQdcKCkpDBKQMCgziGMoPC4VQUckM<div class="post">SHA256 is not like the step from 128 bit to 160 bit.<br/><br/>To use an analogy, it's more like the step from 32-bit to 64-bit address space.&nbsp; We quickly ran out of address space with 16-bit computers, we ran out of address space with 32-bit computers at 4GB, that doesn't mean we're going to run out again with 64-bit anytime soon.<br/><br/>SHA256 is not going to be broken by Moore's law computational improvements in our lifetimes.&nbsp; If it's going to get broken, it'll be by some breakthrough cracking method.&nbsp; An attack that could so thoroughly vanquish SHA256 to bring it within computationally tractable range has a good chance of clobbering SHA512 too.<br/><br/>If we see a weakness in SHA256 coming gradually, we can transition to a new hash function after a certain block number.&nbsp; Everyone would have to upgrade their software by that block number.&nbsp; The new software would keep a new hash of all the old blocks to make sure they're not replaced with another block with the same old hash.</div> text/html