https://en.wikipedia.org/wiki/Cryptographic_hash_function https://en.wikipedia.org/wiki/Cryptographic_hash_function TLDR: they are designed to behave that way.

https://en.wikipedia.org/wiki/Cryptographic_hash_function https://en.wikipedia.org/wiki/Cryptographic_hash_function TLDR: they are designed to behave that way. Their alternative name is "one-way hash function".