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Data::Password::zxcvbn::TimeEstimate(3pm) User Contributed Perl Documentation Data::Password::zxcvbn::TimeEstimate(3pm)


Data::Password::zxcvbn::TimeEstimate - functions to estimate cracking times


version 1.1.2


  use Data::Password::zxcvbn::TimeEstimate qw(estimate_attack_times);
  my $estimates = estimate_attack_times($number_of_guesses);


This module provides functions for back-of-the-envelope crack time estimations, in seconds, based on a few scenarios.



  my $estimates = estimate_attack_times($number_of_guesses);

Returns a hashref with two keys:


hashref of back-of-the-envelope crack time estimations, in seconds, based on a few scenarios:

  • "online_throttling_100_per_hour"

    online attack on a service that rate-limits authentication attempts

  • "online_no_throttling_10_per_second"

    online attack on a service that doesn't rate-limit, or where an attacker has outsmarted rate-limiting.

  • "offline_slow_hashing_1e4_per_second"

    offline attack. assumes multiple attackers, proper user-unique salting, and a slow hash function with moderate work factor, such as bcrypt, scrypt, PBKDF2.

  • "offline_fast_hashing_1e10_per_second"

    offline attack with user-unique salting but a fast hash function like SHA-1, SHA-256 or MD5. A wide range of reasonable numbers anywhere from one billion - one trillion guesses per second, depending on number of cores and machines; ball-parking at 10B/sec.


same keys as "crack_times_seconds", but more useful for display: the values are arrayrefs "["english string",$value]" that can be passed to I18N libraries like "Locale::Maketext" to get localised versions with proper plurals


 my $score = guesses_to_score($number_of_guesses);

Returns an integer from 0-4 (useful for implementing a strength bar):

  • 0

    too guessable: risky password. ("guesses < 10e3")

  • 1

    very guessable: protection from throttled online attacks. ("guesses < 10e6")

  • 2

    somewhat guessable: protection from un-throttled online attacks. ("guesses < 10e8")

  • 3

    safely un-guessable: moderate protection from offline slow-hash scenario. ("guesses < 10e10")

  • 4

    very un-guessable: strong protection from offline slow-hash scenario. ("guesses >= 10e10")


  my ($string,@values) = @{ display_time($time) };
  print My::Localise->get_handle->maketext($string,@values);

Given a $time in seconds, returns an arrayref suitable for "Locale::Maketext", like:

 [ 'quant,_1,day', 23 ]


Gianni Ceccarelli <>


This software is copyright (c) 2022 by BroadBean UK, a CareerBuilder Company.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

2023-04-04 perl v5.36.0