All the methods listed by @kokolegorille are hashing methods that are irreversible, and they are all designed to be slow so that it’s infeasible to brute-force the original password.
- PBKDF2 is CPU-proof (meaning you are unable to crack the original password using only some CPUs) but not GPU-proof.
- BCrypt is both CPU-proof and GPU-proof, but may be vulnerable to quantum computers.
- Argon2 is safe to all known brute-force and rainbow table attacking vectors.
