Raku Land



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.

Licence & Copyright

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

© Jonathan Stowe 2019 - 2021