I'm going to run SHA256 on a password + salt, but I don't know how long to make my VARCHAR when setting up the MySQL database. What is a good length?
Answer
A sha256 is 256 bits long -- as its name indicates.
Since sha256 returns a hexadecimal representation, 4 bits are enough to encode each character (instead of 8, like for ASCII), so 256 bits would represent 64 hex characters, therefore you need a varchar(64), or even a char(64), as the length is always the same, not varying at all.
And the demo :
$hash = hash('sha256', 'hello, world!');
var_dump($hash);
Will give you :
$ php temp.php
string(64) "68e656b251e67e8358bef8483ab0d51c6619f3e7a1a9f0e75838d41ff368f728"
i.e. a string with 64 characters.