Quick function for building a HASH of a file?

Question

Qt

Need a quick function of building a "cast" of the file. Now I use Sha256+MD5. But is there something faster?
ps needed to compare file identity

Answer 1

Do you need a cryptographic hash function or a simple one?
If you do not need to protect yourself from the fact that an attacker will forge a file so that the hash matches, then it is enough to calculate CRC32.

Answer 2

Faster only md5 or sha1

Answer 3

In general, you can take SHA1 for modern hardware and use it safely. If the libraries are updated to normal versions, then new processor instructions specially created for this function will be used.
For a benchmark, you can run openssl speed. There will be a report on all hashing algorithms for your hardware.