How does bcrypt.compare() verify passwords if it uses different salts?

Exactly! In a bcrypt hash, the salt is included in the hashed output. So, when you want to check a password, the bcrypt library will extract the salt from the hash, use it to hash the candidate password, and then compare the two hashes. This is how it ensures security while allowing for password verification.

What you save in the database is basically a combination of the hash and the salt, formatted in such a way that makes both retrievable. It could be something like "hash:salt" or even a fixed length where the first part is the salt and the rest is the hash. When you need to verify a password, you extract the salt and rehash the input password with it.

Yes, the salt is actually a part of the hashed result in bcrypt. It prevents attackers from using precomputed hash tables to crack the hash. When you hash a password, the salt is included in the final result, and it’s crucial for verification. If I remember right, the salt is positioned in the hash string itself, typically between slashes (/).

To add to that, the bcrypt hashing string includes the salt and other details like version and cost factor. So when you call `bcrypt.compare(password, storedHash)`, it automatically retrieves the necessary salt and hashes the provided password using it. Then it simply checks if the two hashes match.