Take for example SHA256. Is it possible for the hash of a 64 character hex string S to be S? i.e:
$$H(S)=S$$
Asked
Active
Viewed 47 times
1
kelalaka
- 48,443
- 11
- 116
- 196
François Huppé
- 113
- 4
-
Does this answer your question? Is there a string that's 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... – kelalaka Jan 12 '22 at 12:37
-
yes it does, thanks – François Huppé Jan 12 '22 at 12:39
-
1+1 for the fast acceptance. Welcome to [cryptography.se] – kelalaka Jan 12 '22 at 13:58
-
1Note that there is a limit to file the size on SHA2 series due to the padding. 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. – kelalaka Jan 12 '22 at 23:15
-
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. – knaccc Jan 13 '22 at 01:15