Speed of Bcrypt

Crypt::Bcrypt can be used to encrypt passwords and it can be told how many times to encrypt the password. The more rounds, the longer it takes to encrypt the password and the longer it takes to verify it. The longer it takes to check one password, the more expensive it would be to mount an attack on the system, even if the encrupted password file leaked to the public.

Let's see how fast the Perl 6 version of Bcrupt works. (Tested on an Macbook Air.)

Note! This site is about Perl 6.
If you are looking for a solution for Perl 5, please check out the Perl 5 tutorial.


use v6;
use Crypt::Bcrypt;

my $password = 'secret';

for 4..17 -> $c {
    my $start = now;
    my $encrypted = bcrypt-hash($password, :rounds($c));
    my $end = now;
    say "hash  {$c}  {$end-$start}";

    $start = now;
    my $valid = bcrypt-match($password, $encrypted);
    $end = now;
    say "match {$c}  {$end-$start}";

hash  4  0.0224464
match 4  0.00190766
hash  5  0.0034416
match 5  0.00318386
hash  6  0.005926
match 6  0.0063915
hash  7  0.01221065
match 7  0.0102838
hash  8  0.024864
match 8  0.0208310
hash  9  0.0460490
match 9  0.044395
hash  10  0.0876536
match 10  0.0847933
hash  11  0.16753307
match 11  0.1677716
hash  12  0.331820
match 12  0.33977756
hash  13  0.6565040
match 13  0.667601
hash  14  1.3052052
match 14  1.3162349
hash  15  2.647807
match 15  2.5993138
hash  16  5.2211821
match 16  5.2359821
hash  17  10.5278777
match 17  10.51981935

12 is the default. You can pass any number between 4-31, but as you can see above 12 it is starting to take quite a lot of time to compute the hash of a password or to verify if a given password matches the hash we have.

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Published on 2017-12-03


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