I am making a messaging system where users are identified by their public keys. It doesn't matter which friendly username they have, so I'm not going to prompt them to choose one. Each user will have a directory that will get their messages saved to, so it would be nice if the directory that belongs to them has a short name. I.e. I can't create a very large directory name by using the entirety of their public keys (might be too long and hit file system limits).
I was considering to use, say,
sha3_244(their_public_key) and consider that hash for their home directory names.
But then I thought, how about I take the 1st 50 bytes of their public key, base32 encode it, and use this instead of the
sha3_244 checksum? Should I be worried about collisions?