What data type to use for hashed password field and what length?

Question

I\'m not sure how password hashing works (will be implementing it later), but need to create database schema now.

I\'m thinking of limiting passwords to 4-20 charact

Answer 1

As a fixed length string (VARCHAR(n) or however MySQL calls it). A hash has always a fixed length of for example 12 characters (depending on the hash algorithm you use). So a 20 char password would be reduced to a 12 char hash, and a 4 char password would also yield a 12 char hash.