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Scrypt password hashing using libsodium

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use Crypt::SodiumScrypt;

my $password =  'somepa55word';

my $hash     =  scrypt-hash($password);

if scrypt-verify($hash, $password ) {

    #  password ok



This module provides a binding to the scrypt password hashing functions provided by libsodium.

The Scrypt algorithm is designed to be prohibitively expensive in terms of time and memory for a brute force attack, so is considered relatively secure. However this means that it might not be suitable for use on resource constrained systems.

The hash returned by scrypt-hash is in the format used in /etc/shadow and can be verified by other libraries that understand the Scrypt algorithm ( such as the libxcrypt that is used for password hashing on some Linuc distributions.) By default the interactive limits for memory and CPU usage are used, which is a reasonable compromise for the time taken for both hashing and verification. If the :sensitive switch is supplied to scrypt-hash then both hashing and verification take significantly longer (and use more memory,) so this may not suitable for some applications.

The scrypt-verify should be able to verify passwords against Scrypt hashes produced by other libraries (that is the hash has the prefix $7$, ) but if you don't have control of the hashing parameters it may take longer than is desirable.


You will need to have C installed for this to work, it is commonly packaged for various Linux distributions, so you should be able to use the usual package management tools.

Assuming that you have a working installation of Rakudo then you should be able to install this with zef :

zef install Crypt::SodiumScrypt

# Or from a local clone

zef install .


If you any suggestions/patches feel free to send them via:


I've tested this with libsodium versions from 13 to 23, but if you find it doesn't work please let me know which version you have installed.

This is free software please see the LICENCE file in the distribution for details.

© Jonathan Stowe 2019 - 2021