Null characters in return buffer

[rflaperuta]

Hello, I've started using the module, but when calling:

var sodium_api = require('sodium').api;

var password_out = sodium_api.crypto_pwhash_argon2i_str(
    new Buffer(password_in),
    sodium_api.crypto_pwhash_OPSLIMIT_INTERACTIVE,
    sodium_api.crypto_pwhash_MEMLIMIT_INTERACTIVE);

password_out is a buffer (as it is supposed to) and contains null characters.

These are not stripped even after calling password_out.toString('ascii').

Although, printing on console using console.log strips them.

Is this by design? How to get rid of the trailing nulls?

The goal is to send the response inside a JSON object like:

var response = {password: password_out.toString('ascii')}

Thanks in advance.

[richchurcher]

Isn't it by design? In the libsodium docs it says,

The generated key has the size defined by the application, no matter what the password length is.

Assuming that the output buffer is always the same size but is null-padded, it would follow that to store the key in a database as a string, you'd need the string to be padded too. Otherwise when you regenerate the key in crypto_pwhash_argon2i_str_verify you'd not end up with the same result.

[jedisct1]

crypto_pwhash_argon2i_STRBYTES represents the maximum length of the returned string.

The string itself can be shorter, and should be trimmed after the first \0, even though the verification function will tolerate padding after it.

[richchurcher]

I see! Thanks, that's helpful.

[rflaperuta]

Do I need to close the Issue Before or After the PR is merged?

Thanks for the help.

[sarahscheffler]

Is it documented somewhere that you have to strip off the \0 bytes? Or is there any interest in removing them automatically? We just had the same issue encoding/decoding from base64 and it took us a little while to track down the error.