Score:1

Is there a string that's it's SHA-256 hash is equal to itself?

cn flag

Take for example SHA256. Is it possible for the hash of a 64 character hex string S to be S? i.e: $$H(S)=S$$

kelalaka avatar
in flag
Does this answer your question? [Is there a string that's hash is equal to itself?](https://crypto.stackexchange.com/questions/19493/is-there-a-string-thats-hash-is-equal-to-itself) Sights, 37 seconds to find the dupe. Well, apart from the theoretical and demonstrative example, we don't know for secure hashes...
François Huppé avatar
cn flag
yes it does, thanks
kelalaka avatar
in flag
+1 for the fast acceptance. Welcome to [cryptography.se]
kelalaka avatar
in flag
Note that there is a limit to file the size on [SHA2 series due to the padding](https://crypto.stackexchange.com/a/64716/18298). Therefore there are inputs that cannot be hashed though one cannot calculate such size for hashing. Your title when read alone can be read as this. I've changed the title to fit the body.
knaccc avatar
es flag
There is such a thing as a "Chameleon hash", where you can cause a collision if you know the private key for a specified public key.
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