sepiroth sepiroth - 1 year ago 96
MySQL Question

When using a SHA256 hash, how long is the hash? (ie, how long should my mysql VARCHAR be?)

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 Source

A sha256 is 256 bits long -- as its name indicates.

If you are using an hexadecimal representation, each digit codes for 4 bits ; so you need 64 digits to represent 256 bits -- so, you need a varchar(64), or a char(64), as the length is always the same, not varying at all.

And the demo :

$hash = hash('sha256', 'hello, world!');

Will give you :

$ php temp.php
string(64) "68e656b251e67e8358bef8483ab0d51c6619f3e7a1a9f0e75838d41ff368f728"

i.e. a string with 64 characters.

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