423
Creating a password in 2023 be like
(programming.dev)
Post funny things about programming here! (Or just rant about your favourite programming language.)
reversibly?
Yeah, you actually better not save the users passwords in plain text or in an encrypted way it could be decrypted. You rather save a (salted) hashed string of the password. When a user logs in you compare the hashed value of the password the user typed in against the hashed value in your database.
What is hashed? Think of it like a crossfoot of a number:
Let's say you have a number 69: It's crossfoot is (6+9) 15. But if someone steals this crossfoot they can't know the original number it's coming from. It could be 78 or 87.
Dumb question: isn't it irrelevant for the malicous party if it's 78 or 87 per your example, because the login only checks the hash anyway? Won't both numbers succesfully login?
It's actually a really good question. What you're explaining is called a collision, by creating the same hash with different numbers you can succesfully login.
This why some standard hashing function become deprecated and are replaced when someone finds a collision. MD5, which was used a lot to hash passwords or files, is considered insecure because of all the collisions people could find.