Something like:
$$ h = Hash(\texttt{"Some String"} \mathbin\| h)$$
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Sign up to join this communitySomething like:
$$ h = Hash(\texttt{"Some String"} \mathbin\| h)$$
Yes, it is possible. You can create many such functions. For instance, define hash function as last 16 symbols or bytes of the original message:
$h(x) = substring(x, length(x)-16, length(x))$
As @kelalaka noticed, it is trivial to find preimages for any hash that fits your requirement. That's why such functions are useless for typical cryptographic purposes.
If you have a cryptographic hash that is not 'broken', yet, essentially the only way to create this special string is through brute force.
Yes, in theory if you apply enough brute force computations, you can find such strings.