NAME
`Crypt::HSXKPasswd' - A secure memorable password generator inspired by
Steve Gibson's Passord Haystacks (https://www.grc.com/haystack.htm), and
the famous XKCD password cartoon (https://xkcd.com/936/).
VERSION
This documentation refers to `Crypt::HSXKPasswd' version 3.6.
SYNOPSIS
use Crypt::HSXKPasswd;
#
# Functional Interface - a shortcut for generating single passwords
#
# generate a single password using the default word source, configuration,
# and random number generator
my $password = hsxkpasswd();
# the above call is simply a shortcut for the following
my $password = Crypt::HSXKPasswd->new()->password();
# this function passes all arguments on to Crypt::HSXKPasswd->new()
# so all the same customisations can be specified, e.g. specifying a
# config preset:
my $password = hsxkpasswd(preset => 'XKCD');
#
# Object Oriented Interface - recommended for generating multiple passwords
#
# create a new instance with the default dictionary, config, and random
# number generator
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new();
# generate a single password
my $password = $hsxkpasswd_instance->password();
# generate multiple passwords
my @passwords = $hsxkpasswd_instance->passwords(10);
DESCRIPTION
A secure memorable password generator inspired by the wonderful XKCD
webcomic at http://www.xkcd.com/ and Steve Gibson's Password Haystacks
page at https://www.grc.com/haystack.htm. This is the Perl module that
powers https://www.xkpasswd.net.
PHILOSOPHY
More and more of the things we do on our computer require passwords, and
at the same time it seems we hear about organisations or sites losing
user database on every day that ends in a *y*. If we re-use our
passwords we expose ourself to an ever greater risk, but we need more
passwords than we can possibly remember or invent. Coming up with one
good password is easy, but coming up with one good password a week is a
lot harder, let alone one a day!
Obviously we need some technological help. We need our computers to help
us generate robust password and store them securely. There are many
great password managers out there to help us securely store and sync our
passwords, including commercial offerings and open-source projects. Many
of these managers also offer to generate random passwords for us,
usually in the form of a random string of meaningless letters numbers
and symbols. These kinds of nonsense passwords are certainly secure, but
they are often impractical.
Regardless of how good your chosen password manager is, there will
always be times when you need to type in your passwords, and that's when
random gibberish passwords become a real pain point. As annoying as it
is to have to glance over and back at a small cellphone screen to
manually type a gibberish password into a computer, that's nothing
compared to the annoyance of trying to communicate such a password to a
family member, friend, colleague or customer over the phone.
Surely it would be better to have passwords that are still truly random
in the way humans can't be, but are also human-friendly in the way
random gibberish never will be? This is the problem this module aims to
solve.
Rather than randomly choosing many letters, digits, and symbols from a
fairly small alphabet of possible characters, this library chooses a
small number of words from a large *alphabet* of possible words as the
basis for passwords. Words are easy to remember, easy to read from a
screen, easy to type, and easy to communicate over the telephone.
This module uses words to make up the bulk of the passwords it
generates, but it also adds carefully placed symbols and digits to add
security without making the passwords difficult to remember, read, type,
and speak.
In shot, this module is for people who prefer passwords that look like
this:
!15.play.MAJOR.fresh.FLAT.23!
to passwords that look like this:
eB8.GJXa@TuM
PASSWORD GENERATION ALGORITHM
This module always uses a simple five-step algorithm to generate
passwords, but each step can be customised, and many steps can be
skipped completely.
It's important to understand the algorithm before trying to create your
own custom configurations for this module.
The algorithm is broken in to the following steps:
1 Pick random words from the dictionary.
2 Apply transformations to the words.
3 Create pseudo-words made up for randomly chosen digits and add them
as the first and last words.
4 Insert a copy of the same symbol between each of the words and
pseudo-words. This symbol is referred to as the *separator
character*.
5 Pad the password with multiple instances of the same symbol front
and/or back. This symbol is referred to as the *padding character*.
You can visualise this process as follows:
correct horse batter staple
correct HORSE battery staple
25 correct HORSE battery staple 83
25*correct*HORSE*battery*staple*83
++25*correct*HORSE*battery*staple*83++
Each of these steps can be customised in the following ways:
1 The number of words to be used, and the minimum and maximum lengths
of the words can be configured.
2 The case of the words can be modified in a number of ways, including
randomly choosing the case for each word.
It is also possible to specify so-called *133t-style* character
substitutions, e.g. replacing all occurrences of the letter `e' with
the digit `3', or all occurrences of the letter `s' with the symbol
`$'.
3 The number of digits to add as pseudo words to the front and back of
the password can be configured. A length of zero can be specified
for both to generate passwords without any randomly chosen digits.
4 The separator character can be specified directly, or it can be
randomly chosen from a list of symbols. It is also possible to
specify that no separator should be used.
5 The padding character can also be specified directly, or remotely
chosen from a list of possible symbols. Padding can also be disabled
completely. If padding is to be used it can be applied in two modes
- fixed, and adaptive.
With fixed padding a specified number of copies of the separator
character are added to the front and back of the password. The fixed
padding does not have to be symmetric.
With adaptive padding the required number of copies of the separator
character are added to the back of the password until it reaches a
specified length.
THE MATHS
Before examining the password strength of passwords generated with this
module we need to lay out the relatively simple maths underlying it all.
Maths Primer
A coin could be used as a very simple password generator. Each character
in the password would be the result of a single coin toss. If the coin
lands heads up, we add a `H' to our password, if it lands tails up, we
add a `T'.
If you made a one-letter password in this way there would only be two
possibilities, `H', or `T', or two permutations. If you made a
two-letter password in this way there would be four possible
combinations, or permutations, `HH', `HT', `TH', and `TT'. If you made a
three-character password in this way there would be 16 permutations, a
five character one would have 32 permutations, and so forth.
So, for a coin toss, which has two possible values for each character,
the formula for the number of permutations `P' for a given length of
password `L' is:
P = 2^L
Or, two to the power of the length of the password.
If we now swapped our coin for a dice, we would go from two possible
values per letter, to six possible values per letter. For one dice roll
there would be six permutations, for two there would be 36, for three
there would be 108 and so on.
This means that for a dice, the number of permutations can be calculated
with the formula:
P = 6^L
When talking about passwords, the set of possible symbols used for each
character in the password is referred to as the password's *alphabet*.
So, for the coin toss the alphabet was just `H' and `T', and for the
dice it was `1', `2', `3', `4', `5', and `6'. The actual characters used
in the alphabet make no difference to the strength of the password, all
that matters is the size of the alphabet, which we'll call `A'.
As you can probably infer from the two examples above, the formula for
the number of possible permutations `P' for a password of length `L'
created from an alphabet of size `A' is:
P = A^L
In the real world our passwords are generally made up of a mix of
letters, digits, and symbols. If we use mixed case that gives us 52
letters alone, then add in the ten digits from `0' to `9' and we're
already up to 62 possible characters before we even start on the array
of symbols and punctuation characters on our keyboards. It's generally
accepted that if you include symbols and punctuation, there are 95
characters available for use in randomly generated passwords. Hence, in
the real-world, the value for `A' is assumed to be 95. When you start
raising a number as big as 95 to even low powers the number of
permutations quickly rises.
A two character password with alphabet of 95 has 9025 permutations,
increasing the length to three characters brings that up to 857,375, and
so on. These numbers very quickly become too big to handle. For just an
8 character password we are talking about 6,634,204,312,890,625
permutations, which is a number so big most people couldn't say it (what
do you call something a thousand times bigger than a trillion?).
Because the numbers get so astronomically big so quickly, computer
scientists use bits of entropy to measure password strength rather than
the number of permutations. The formula to turn permutations into bits
of entropy `E' is very simple:
E = Log(2)P
In other words, the entropy is the log to base two of the permutations.
For our eight character example that equates to about 52 bits.
There are two approaches to increasing the number of permutations, and
hence the entropy, you can choose more characters, or, you can make the
alphabet you are choosing from bigger.
The Entropy of HSXKPasswd Passwords
Exactly how much entropy does a password need? That's the subject of
much debate, and the answer ultimately depends on the value of the
assets being protected by the password.
Two common recommendations you hear are 8 characters containing a mix of
upper and lower case letters, digits, and symbols, or 12 characters with
the same composition. These evaluation to approximately 52 bits of
entropy and 78 bits of entropy respectively.
When evaluating the entropy of passwords generated by this module, it
has to be done from two points of view for the answer to be meaningful.
Firstly, a best-case scenario - the attacker has absolutely no knowledge
of how the password was generated, and hence must mount a brute-force
attack. Then, secondly from the point of view of an attacker with full
knowledge of how the password was generated. Not just the knowledge that
this module was used, but a copy of the dictionary file used, and, a
copy of the configuration settings used.
For the purpose of this documentation, the entropy in the first
scenario, the brute force attack, will be referred to as the blind
entropy, and the entropy in the second scenario the seen entropy.
The blind entropy is solely determined by the configuration settings,
the seen entropy depends on both the settings and the dictionary file
used.
Calculating the bind entropy `Eb' is quite straightforward, we just need
to know the size of the alphabet resulting from the configuration `A',
and the minimum length of passwords generated with the configuration
`L', and plug those values into this formula:
Eb = Log(2)(A^L)
Calculating `A' simply involves determining whether or not the
configuration results in a mix of letter cases (26 or 52 characters),
the inclusion of at least one symbol (if any one is present, assume the
industry standard of a 33 character search space), and the inclusion of
at least one digit (10 character). This will result in a value between
26 and 95.
Calculating `L' is also straightforward. The one minor complication is
that some configurations result in a variable length password. In this
case, assume the shortest possible length the configuration could
produce.
The example password from the PHILOSOPHY section
(`!15.play.MAJOR.fresh.FLAT.23!') was generated using the preset
`WEB32'. This preset uses four words of between four and five letters
long, with the case of each word randomly set to all lower or all upper
as the basis for the password, it then chooses two pairs of random
digits as extra words to go front and back, before separating each word
with a copy of a randomly chosen symbol, and padding the front and back
of the password with a copy of a different randomly chosen symbol. This
results in passwords that contain a mix of cases, digits, and symbols,
and are between 27 and 31 characters long. If we add these values into
the formula we find that the blind entropy for passwords created with
this preset is:
Eb = Log(2)(95^27) = 163 bits
This is spectacularly secure! And, this is the most likely kind of
attack for a password to face. However, to have confidence in the
password we must also now calculate the entropy when the attacker knows
everything about how the password was generated.
We will calculate the entropy resulting from the same `WEB32' config
being used to generate a password using the sample library file that
ships with the module.
The number of permutations the attacker needs to check is purely the
product of possibly results for each random choice made during the
assembly of the password.
Lets start with the words that will form the core of the password. The
configuration chooses four words of between four and five letters long
from the dictionary, and then randomises their case, effectively making
it a choice from twice as many words (each word in each case).
The sample dictionary file contains 698 words of the configured length,
which doubles to 1396. Choosing four words from that very large alphabet
gives a starting point of `1396^4', or 3,797,883,801,856 permutations.
Next we need to calculate the permutations for the separator character.
The configuration specifies just nine permitted characters, and we
choose just one, so that equates to 9 permutations.
Similarly, the padding character on the end is chosen from 13 permitted
symbols giving 13 more permutations.
Finally, there are four randomly chosen digits, giving `10^4', or 10,000
permutations.
The total number of permutations is the product of all these
permutations:
Pseen = 3,797,883,801,856 * 9 * 13 * 10,000 = 2.77x10^17
Finally, we convert this to entropy by taking the base 2 log:
Eseen = Log(2)2.77x10^17 = ~57bits
What this means is that most probably, passwords generated with this
preset using the sample dictionary file are spectacularly more secure
than even 12 randomly chosen characters, and, that in the very unlikely
event that an attackers knows absolutely everything about how the
password was generated, it is still significantly more secure than 8
randomly chosen characters.
Because the exact strength of the passwords produced by this module
depend on the configuration and dictionary file used, the constructor
does the above math when creating an HSXKPasswd object, and throws a
warning if either the blind entropy falls below 78bits, or the seen
entropy falls below 52 bits.
SUBROUTINES/METHODS
MODULE CONFIGURATION
It is possible to tweak the module's behaviour in certain areas by
updating the values contained within a set of module configuration keys.
The values associated with these keys can be accessed and updated via
the class function `module_config()'.
# get the current debug status
my $debug_status = Crypt::HSXKPasswd->module_config('DEBUG');
# configure the module to suppress all entropy warnings
Crypt::HSXKPasswd->module_config('ENTROPY_WARNINGS', 'NONE');
The following module configuration keys exist within the module:
* `DEBUG' - A True/False value denoting whether or not the module
should print debug messages. The default is not to print debug
messages.
For more details see the DIAGNOSTICS section of this document.
* `LOG_ERRORS' - A True/False value denoting whether or not errors
should be logged. The default is not to log.
For more details see the DIAGNOSTICS section of this document.
* `LOG_STREAM' - the stream to which debug messages should be printed
if debugging is enabled, and log messages should be printed when
error logging is enabled. The default is to print to `STDERR'.
For more details see the DIAGNOSTICS section of this document.
* `ENTROPY_MIN_BLIND' - the minimum allowable entropy against brute
force attacks in bits. The default is 78 bits.
For more details see the ENTROPY CHECKING section of this document.
* `ENTROPY_MIN_SEEN' - the minimum allowable entropy against an
attacker with full knowledge. The default is 52 bits.
For more details see the ENTROPY CHECKING section of this document.
* `ENTROPY_WARNINGS' - control the emission of entropy warnings. The
value must be one of `ALL', `BLIND', or `NONE'. The default value is
`ALL'.
For more details see the ENTROPY CHECKING section of this document.
CUSTOM DATA TYPES
This module uses a custom type library created with `Type::Library' for
data validation. It is important to know this for two reasons - firstly,
these custom types are mentioned in many error messages, and secondly
these custom types are available for developers to use in their own
code, either when utilising `Crypt::HSXKPasswd', or writing custom word
sources by extending `Crypt::HSXKPasswd::Dictionary', or when writing
custom random number generators by extending `Crypt::HSXKPasswd::RNG'.
Defined Types
* `NonEmptyString' - a string containing at least one character.
* `PositiveInteger' - a whole number greater than or equal to zero.
* `NonZeroPositiveInteger' - a whole number greater than zero.
* `TrueFalse' - a reasonable boolean value, specifically, `undef', and
empty string, or 0 to indicate false, and a 1 to indicate true.
* `PerlPackageName' - string representing a valid Perl package name
like `Crypt::HSXKPasswd::Dictionary::NL'.
* `Letter' - a string containing a single letter. Because this module
is Unicode-aware, it should be noted that a letter is defined as a
single Unicode grapheme with the Unicode property `Letter'. What
this means is that accented letters like `é' are considered valid,
as are ligatures like `æ'.
* `Symbol' - a string containing a single non-letter character.
Because this module is Unicode-aware, should be noted that a
non-letter character is defined as a single Unicode grapheme that
does not have the Unicode property `Letter'. What this means is that
neither letters, accented characters, nor ligatures can be used as
symbols, but just about every other Unicode character can, including
punctuation symbols, mathematical symbols, and even emoji!
* `Word' - a string containing only letters (as defined by the type
`Letter'), and at least four long.
* `SymbolAlphabet' - a symbol alphabet is a reference to an array that
contains at least two distinct symbols (as defined by the type
`Symbol'), and no values that are not symbols.
* `WordLength' - a valid value when specifying the length of a word,
specifically, a whole number greater than or equal to four.
* `ConfigKeyDefinition' - a valid configuration key definition. A
reference to a hash mapping `required' to a true/false value,
`expects' to a non-empty string, and `type' to a `Type::Tiny'
object.
* `ConfigKeyName' - a valid configuration key name, see the
CONFIGURATION section of this document for a description of each
configuration key supported by this module. You can get a list of
valid configuration key names programatically by calling the
function `Crypt::HSXKPasswd-'defined_config_keys()>.
* `ConfigKeyAssignment' - a mapping between a valid configuration key
name and a valid value for that configuration key.
* `ConfigOverride' - a reference to hash containing one or more
configuration key assignments as defined by the type
`ConfigKeyAssignment'.
* `Config' - a reference to a hash that contains a complete and valid
set of mappings between configuration key names and values. For a
config to be considered valid it must contain only valid valid
configuration key assignments as defined by the type
`ConfigKeyAssignment', must contain a configuration key assignment
for each required configuration key and all interdependencies
between the specified configuration key assignments must be
fulfilled.
See the CONFIG section of this document for a detailed description
of each of the defined configuration keys and their various
interdependencies.
* `PresetDefinition' - a valid preset definition. A reference to a
hash mapping `description' to a non-empty string, and `config' to a
valid Config.
* `PresetName' - a valid preset name, see the PRESETS section of this
document for a description of each preset supported by this module.
You can get a list of valid preset names programatically by calling
the function `Crypt::HSXKPasswd-'defined_presets()>.
Using the Custom Types
The library of custom types is defined in the package
`Crypt::HSXKPasswd::Types', and it is a standard `Type::Library' type
library containing `Type::Tiny' type definitions.
Useful Links:
* The documentation for `Type::Tiny' -
http://search.cpan.org/perldoc?Type%3A%3ATiny
* The documentation for `Type::Library' -
http://search.cpan.org/perldoc?Type%3A%3ALibrary
To use the bare type definitions listed above, import the module as
follows:
use Crypt::HSXKPasswd::Types qw( :types );
Each type listed above will now be imported, and become available as a
bare word. The `Type::Tiny' documentation provides a full list of
available functions, but the examples below illustrate some of the more
useful ones:
$is_valid = Letter->check('e'); # $is_valid = 1
$is_valid = Letter->check('-'); # $is_valid = undef
$err_msg = Letter->validate('e'); # $err_msg = undef
$err_msg = Letter->validate('-'); # $err_msg = "'-' is not a Letter ...
# ... (must be a string containing exactly one letter)"
`Type::Library' automatically creates an `is_TypeName' function for each
type defined in the library. These are not imported by default. To
import them add the export tag `:is' to the `use' line. I would
recommend the following `use' line:
use Crypt::HSXKPasswd::Types qw( :types :is );
You can now do things like the following:
$is_valid = is_Letter('e'); # $is_valid = 1
$is_valid = is_Letter('-'); # $is_valid = undef
Each of the types listed above also contains a custom function using
`Type::Tiny''s new, and still officially experimental, `my_methods'
feature. The custom function is called `my_english', and can be used to
return an English description of the values considered valid by the
type, e.g.:
print Letter->my_english(); # prints: a string containing exactly one letter
As well as the named types listed above, there are also anonymous types
defined for each supported configuration key. These can be accessed
using the function `Crypt::HSXKPasswd-'config_key_definitions()>.
If declaring your own `Type::Tiny' types, you may also find the public
subroutine `Crypt::HSXKPasswd::Types::var_to_string()' useful - it will
turn anything passed as a scalar into a meaningful string, truncating
any resulting strings longer than 72 characters in nice way. All the
custom error messages in all the types defined in
`Crypt::HSXKPasswd::Types' make use of this subroutine.
CONFIGURATION
The module builds passwords using the following process.
First, a set of words are randomly chosen from the word source. Then,
two pseudo-words made of one or more digits may added before and/or
after the words from. Next, a separator character may be placed between
all the words (including the groups of digits), and one or more
occurrences of a padding symbol may be added front and/or back.
You can envisage the process as follows:
correct HORSE BATTERY staple
34 correct HORSE BATTERY staple 56
34-correct-HORSE-BATTERY-staple-56
!!34-correct-HORSE-BATTERY-staple-56!!
Many aspects of this password generation process are configurable. You
can control the length and number of words chosen, and what, if any,
case transformations should be applied to those words, and how accented
characters should be treated. How many, if any, digits should be added
front and back. What symbol, if any, should be used as a separator. And
finally how the password should be padded, if at all, and with what
symbol. Passwords can be padded to a given length, or by a given number
of symbols front and back.
The symbols used as the separator and for padding can be explicitly
specified, or the they can be randomly chosen from a given alphabet of
possible symbols. Both symbols can be randomly chosen from the same
alphabet, or from two separately specified alphabets.
Every instance of an HSXKPasswd password generator stores its
configuration as a set of name-value pairs, referred to as
*configuration keys* throughout this documentation.
Configurations can be specified either as a complete set of
configuration keys with values that together form a valid configuration,
as a named preset, or, as a named preset accompanied by a list of one or
more configuration keys with new values to override those specified by
the preset.
The module contains a preset called `DEFAULT', and this preset is used
if no configuration is specified. The function `default_config()' will
return a copy of this configuration as a reference to a hashtable.
For more details on how to specify configurations, see the documentation
for the constructor (the function `new()') below.
Password Generator Configuration Keys
Below is a list of all the configuration keys that can be used to
customise the password generation algorithm. Each configuration key is
accompanied by a description of what aspect of the algorithm they
control, and any validation rules that apply to the key.
Note that some keys are always required, and that there are dependencies
between keys. For examples, if you specify that the separator symbol
should be chosen at random, you must also specify an alphabet from which
the symbol should be randomly chosen.
* `allow_accents' (optional) - if not specified, or if a falsy value
is specified, accents will be removed from letters in the generated
passwords. E.g. `é' becomes `e'. If a truthy value is specified,
accents will be preserved, and appear in the generated passwords.
* `case_transform' (required) - the transformations, if any, that
should be applied to the words that appear in the generated
passwords. The value specified must be one of the following:
* `ALTERNATE' - each alternate word will be converted to all upper
case and all lower case. The case of the first word is chosen at
random.
* `CAPITALISE' - the first letter in every word will be converted
to upper case, all other letters will be converted to lower
case.
* `INVERT' - the first letter in every word will be converted to
lower case, all other letters will be converted to upper case.
* `LOWER' - all letters in all the words will be converted to
lower case. Use of this option is strongly discouraged for
security reasons.
* `NONE' - the case of the letters that make up the words will not
be altered from how they were specified in the original word
source.
* `RANDOM' - each word will be randomly converted to all upper
case or all lower case.
* `UPPER' - all letters in all the words will be converted to
upper case. Use of this option is strongly discouraged for
security reasons.
The function `default_config()' returns a value of `CAPITALISE' for
this key.
* `character_substitutions' (optional) - a reference to a hashtable
containing containing zero or more character substitutions to be
applied to the randomly chosen words when generating passwords. The
keys in the hashtable must be single letters. The substitutions can
contain multiple characters. Specifying one or more substitutions
with a length greater than one could lead to passwords being longer
than expected, and to entropy calculations being under estimated.
The module will issue a warning when such a config is loaded.
* `num_words' (required) - the number of words to randomly choose from
the word source as the basis for the generated passwords.
The function `default_config()' returns a value of `3' for this key.
* `pad_to_length' (conditionally required) - the length generated
passwords must be padded to when using adaptive padding, i.e. when
`padding_type' is set to `ADAPTIVE'). The value must be an integer
greater than or equal to 12. Lengths of less than 12 are not
permitted for security reasons.
* `padding_alphabet' (optional) - this key is ignored unless the
configuration specifies that the padding character should be
randomly chosen, i.e. unless `padding_character' is set to `RANDOM'.
When the padding character is set to be randomly chosen, the module
will check for the presence of this key. If it is specified, the
padding character will be randomly chosen from the set of symbols
defined by this key. If this key is not set, the module will use the
set of symbols specified by the key `symbol_alphabet'. If neither
this key nor `symbol_alphabet' are specified, then the configuration
will be considered invalid.
If specified, this key must be a reference to an array of
single-character strings.
* `padding_character' (conditionally required) - this key is unless
the key `padding_type' is set to `NONE'. It specifies the padding
symbol to be used when generating passwords.
If specified, they key's value must be a single character string, or
one of the following special values:
* `RANDOM' - the character should be randomly chosen from the set
of characters specified by the key `padding_alphabet' or
`symbol_alphabet'. If specified, `padding_alphabet' takes
precedence over `symbol_alphabet'. If this value is specified
for `padding_character', and neither `padding_alphabet' nor
`symbol_alphabet' are specified, the configuration will be
considered invalid.
* `SEPARATOR' - pad the password with the same symbol that is used
to separate the words. The key `padding_character' cannot be set
to `SEPARATOR' when the key `separator_character' is set to
`NONE'.
The function `default_config' return the value `RANDOM' for this
key.
* `padding_characters_before' & `padding_characters_after'
(conditionally required) - both of these keys are required if the
key `padding_type' is set to `FIXED'.
These keys specify the number of padding symbols that should be
added to the front and back of the password.
Both keys require that the specified value be an integer greater
than or equal to zero.
The function `default_config()' returns a value of `2' for both of
these keys.
* `padding_digits_before' & `padding_digits_after' (required) - the
number of random digits to include before and after the randomly
chosen words when generating passwords.
Both keys require that the specified value be an integer greater
than or equal to zero.
The function `default_config()' returns a value of `2' for both of
these keys.
* `padding_type' (required) - the way in which padding symbols should
be added when generating passwords.
Only the following values are valid for this key:
* `NONE' - do not add any padding symbols when generating
passwords.
* `FIXED' - add an exactly specified number of copies of the
padding symbol to the front and back of generated passwords.
When they key `padding_type' is set to `FIXED', the three keys
`padding_character', `padding_characters_before' &
`padding_characters_after' become required.
* `ADAPTIVE' - add no copies of the padding symbol will be added
to the front of the generated passwords, and copies of the
padding character will be added to the end of the generated
passwords until the total length of the password is equal to the
value specified for the key `pad_to_length'.
Note that If the password is longer than the value specified by
the key `pad_to_length' before any copies of the padding symbol
are added, the password will be truncated to the length
specified by the key `pad_to_length'.
When they key `padding_type' is set to `ADAPTIVE', the three
keys `padding_character', `padding_characters_before' &
`padding_characters_after' become required.
The function `default_config()' returns a value of `FIXED' for this
key.
* `separator_alphabet' (optional) - this key is ignored unless the
configuration specifies that the separator character should be
randomly chosen, i.e. unless `separator_character' is set to
`RANDOM'.
When the separator character is set to be randomly chosen, the
module will check for the presence of this key. If it is specified,
the separator character will be randomly chosen from the set of
symbols defined by this key. If this key is not set, the module will
use the set of symbols specified by the key `symbol_alphabet'. If
neither this key nor `symbol_alphabet' are specified, then the
configuration will be considered invalid.
If specified, this key must be a reference to an array of
single-character strings.
* `separator_character' (required) - the symbol to use to separate the
words when generating passwords.
The value specified for this key must be a single-character string,
or one of the following special values:
* `NONE' - no separator character will be used. I.e. the words,
and the groups of digits before and after the words, if any,
will be directly joined together.
`RANDOM' - a single character will be randomly chosen from the
list of symbols specified by one of the keys
`separator_alphabet' or `symbol_alphabet'. If both keys are set,
`separator_alphabet' takes precedence.
The function `default_config()' returns a value of `RANDOM' for this
key.
* `symbol_alphabet' (optional) - this key specifies a default alphabet
of symbols that can be used when either or both the separator
character and the padding character are set to be chosen at random.
I.e. when either or both of the keys `separator_character' and
`padding_character' are set to `RANDOM'.
Note that the keys `separator_alphabet' and `padding_alphabet' take
precedence over this key if specified.
The value specified for this key must be a reference to an array of
single-character strings.
The function `default_config()' returns a value of `['!', '@', '$',
'%', '^', '&', '*', '-', '_', '+', '=', ':', '|', '~', '?', '/',
'.', ';']' for this key.
* `word_length_min' & `word_length_max' (required) - the minimum and
maximum length of the words that will form the basis of the
generated passwords.
The values specified for both keys must be integers greater than
three, and the value specified for `word_length_max' must be greater
than or equal to the value specified for `word_length_min'.
The function `default_config()' returns values of `4' and `8' for
these keys.
PRESETS
Below is a list of all the presets defined by this module.
This information can be accessed programatically using the functions
`defined_presets()', `presets_to_string()', `preset_description()', and
`preset_config()'.
* `APPLEID' - a preset respecting the many prerequisites Apple places
on Apple ID passwords. Apple's official password policy cam be found
at the following URL: http://support.apple.com/kb/ht4232. Note that
Apple's knowledge base article omits to mention that passwords can't
be longer than 32 characters. This preset is also configured to use
only characters that are easy to type on the standard iOS keyboard,
i.e. those appearing on the letters keyboard (`ABC') or the numbers
keyboard `.?123', and not those on the harder to reach symbols
keyboard `#+='.
Sample Password:
-25,favor,MANY,BEAR,53-
Preset Definition:
{
padding_alphabet => [qw{- : . ! ? @ &}],
separator_alphabet => [qw{- : . @}, q{,}, q{ }],
word_length_min => 4,
word_length_max => 7,
num_words => 3,
separator_character => 'RANDOM',
padding_digits_before => 2,
padding_digits_after => 2,
padding_type => 'FIXED',
padding_character => 'RANDOM',
padding_characters_before => 1,
padding_characters_after => 1,
case_transform => 'RANDOM',
allow_accents => 0,
}
* `DEFAULT' - the default configuration.
Sample Password:
~~12:settle:SUCCEED:summer:48~~
Preset Definition:
{
symbol_alphabet => [qw{! @ $ % ^ & * - _ + = : | ~ ? / . ;}],
word_length_min => 4,
word_length_max => 8,
num_words => 3,
separator_character => 'RANDOM',
padding_digits_before => 2,
padding_digits_after => 2,
padding_type => 'FIXED',
padding_character => 'RANDOM',
padding_characters_before => 2,
padding_characters_after => 2,
case_transform => 'ALTERNATE',
allow_accents => 0,
}
* `NTLM' - a preset for 14 character NTMLv1 (NTLM Version 1)
passwords. ONLY USE THIS PRESET IF YOU MUST! The 14 character limit
does not allow for sufficient entropy in scenarios where the
attacker knows the dictionary and config used to generate the
password. Use of this preset will generate a low entropy warning.
Sample Password:
0=mAYAN=sCART@
Preset Definition:
{
padding_alphabet => [qw{! @ $ % ^ & * + = : | ~ ?}],
separator_alphabet => [qw{- + = . * _ | ~}, q{,}],
word_length_min => 5,
word_length_max => 5,
num_words => 2,
separator_character => 'RANDOM',
padding_digits_before => 1,
padding_digits_after => 0,
padding_type => 'FIXED',
padding_character => 'RANDOM',
padding_characters_before => 0,
padding_characters_after => 1,
case_transform => 'INVERT',
allow_accents => 0,
}
* `SECURITYQ' - a preset for creating fake answers to security
questions. This preset generates long nonsense sentences ending in
`.' `!' or `?'.
Sample 'Password':
Wales outside full month minutes gentle?
Preset Definition:
{
word_length_min => 4,
word_length_max => 8,
num_words => 6,
separator_character => q{ },
padding_digits_before => 0,
padding_digits_after => 0,
padding_type => 'FIXED',
padding_character => 'RANDOM',
padding_alphabet => [qw{. ! ?}],
padding_characters_before => 0,
padding_characters_after => 1,
case_transform => 'NONE',
allow_accents => 0,
}
* `WEB16' - a preset for websites that don't allow passwords to be
longer than 16 characters. ONLY USE THIS PRESET IF YOU MUST! The 14
character limit does not allow for sufficient entropy in scenarios
where the attacker knows the dictionary and config used to generate
the password. Use of this preset will generate a low entropy
warning.
Sample Password:
tube+NICE+iron+02
Preset Definition:
{
symbol_alphabet => [qw{! @ $ % ^ & * - _ + = : | ~ ? / . ;}],
word_length_min => 4,
word_length_max => 4,
num_words => 3,
separator_character => 'RANDOM',
padding_digits_before => 0,
padding_digits_after => 2,
padding_type => 'NONE',
case_transform => 'RANDOM',
allow_accents => 0,
}
* `WEB32' - a preset for websites that don't allow passwords to be
longer than 32 characters.
Sample Password:
+93-took-CASE-money-AHEAD-31+
Preset Definition:
{
padding_alphabet => [qw{! @ $ % ^ & * + = : | ~ ?}],
separator_alphabet => [qw{- + = . * _ | ~}, q{,}],
word_length_min => 4,
word_length_max => 5,
num_words => 4,
separator_character => 'RANDOM',
padding_digits_before => 2,
padding_digits_after => 2,
padding_type => 'FIXED',
padding_character => 'RANDOM',
padding_characters_before => 1,
padding_characters_after => 1,
case_transform => 'ALTERNATE',
allow_accents => 0,
}
* `WIFI' - a preset for generating 63 character long WPA2 keys (most
routers allow 64 characters, but some only allow 63, hence the
somewhat unexpected length).
Sample Password:
2736_ITSELF_PARTIAL_QUICKLY_SCOTLAND_wild_people_7441!!!!!!!!!!
Preset Definition:
{
padding_alphabet => [qw{! @ $ % ^ & * + = : | ~ ?}],
separator_alphabet => [qw{- + = . * _ | ~}, q{,}],
word_length_min => 4,
word_length_max => 8,
num_words => 6,
separator_character => 'RANDOM',
padding_digits_before => 4,
padding_digits_after => 4,
padding_type => 'ADAPTIVE',
padding_character => 'RANDOM',
pad_to_length => 63,
case_transform => 'RANDOM',
allow_accents => 0,
}
* `XKCD' - a preset inspired by the original XKCD comic
(http://xkcd.com/936/), but with some alterations to provide
sufficient entropy to avoid low entropy warnings.
Sample Password:
quiet-children-OCTOBER-today-HOPE
Preset Definition:
{
word_length_min => 4,
word_length_max => 8,
num_words => 5,
separator_character => q{-},
padding_digits_before => 0,
padding_digits_after => 0,
padding_type => 'NONE',
case_transform => 'RANDOM',
allow_accents => 0,
}
FUNCTIONAL INTERFACE
Although the package was primarily designed to be used in an
object-oriented way, there is a functional interface too. The functional
interface initialises an object internally and then uses that object to
generate a single password. If you only need one password, this is no
less efficient than the object-oriented interface, however, if you are
generating multiple passwords it is much less efficient.
There is only a single function exported by the module:
hsxkpasswd()
my $password = hsxkpasswd();
This function call is equivalent to the following Object-Oriented code:
my $password = Crypt::HSXKPasswd->new()->password();
This function passes all arguments it receives through to the
constructor, so all arguments that are valid in `new()' are valid here.
This function Croaks if there is a problem generating the password.
Note that it is inefficient to use this function to generate multiple
passwords because the dictionary will be re-loaded, and the entropy
stats re-calculated each time the function is called.
CONSTRUCTOR
# create a new instance with the default dictionary, config, and random
# number generator
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new();
# the constructor takes optional named arguments, these can be used to
# customise the word source, config, and random number source.
# create an instance that uses the UNIX words file as the word source
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(
dictionary => Crypt::HSXKPasswd::Dictionary::System->new()
);
# create an instance that uses an array reference as the word source
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(dictionary_list => $array_ref);
# create an instance that uses a dictionary file as the word source
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(
dictionary_file => 'sample_dict_EN.txt'
);
# the class Crypt::HSXKPasswd::Dictionary::Basic can be used to aggregate
# multiple array refs and/or dictionary files into a single word source
my $dictionary = Crypt::HSXKPasswd::Dictionary::Basic->new();
$dictionary->add_words('dict1.txt');
$dictionary->add_words('dict2.txt');
$dictionary->add_words($array_ref);
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(dictionary => $dictionary);
# create an instance from the preset 'XKCD'
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(preset => 'XKCD');
# create an instance based on the preset 'XKCD' with one customisation
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(
preset => 'XKCD',
preset_override => {separator_character => q{ }}
);
# create an instance from a config based on a preset
# but with many alterations
my $config = Crypt::HSXKPasswd->preset_config('XKCD');
$config->{separator_character} = q{ };
$config->{case_transform} = 'INVERT';
$config->{padding_type} = "FIXED";
$config->{padding_characters_before} = 1;
$config->{padding_characters_after} = 1;
$config->{padding_character} = '*';
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(config => $config);
# create an instance from an entirely custom configuration
my $config = {
padding_alphabet => [qw{! @ $ % ^ & * + = : ~ ?}],
separator_alphabet => [qw{- + = . _ | ~}],
word_length_min => 6,
word_length_max => 6,
num_words => 3,
separator_character => 'RANDOM',
padding_digits_before => 2,
padding_digits_after => 2,
padding_type => 'FIXED',
padding_character => 'RANDOM',
padding_characters_before => 2,
padding_characters_after => 2,
case_transform => 'CAPITALISE',
}
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(config => $config);
# create an instance from an entire custom config passed as a JSON string
# a convenient way to use configs generated using the web interface at
# https://xkpasswd.net
my $config = <<'END_CONF';
{
"num_words": 4,
"word_length_min": 4,
"word_length_max": 8,
"case_transform": "RANDOM",
"separator_character": " ",
"padding_digits_before": 0,
"padding_digits_after": 0,
"padding_type": "NONE",
}
END_CONF
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(config_json => $config);
# create an instance which uses /dev/urandom as the RNG
# (only possible on Linux/Unix only systems)
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(
rng => Crypt::HSXKPasswd::RNG::DevUrandom->new();
);
# create an instance which uses Random.Org as the random number generator
# NOTE - this should be used sparingly, and only by the paranoid. If you
# abuse this RNG your IP will get blacklisted on Random.Org. You must pass
# a valid email address to the constructor for
# Crypt::HSXKPasswd::RNG::RandomDorOrg because Random.Org's usage
# guidelines request that all invocations to their API contain a contact
# email in the useragent header, and this module honours that request.
my $hsxkpasswd_instance = Crypt::HSXKPasswd->new(
rng => Crypt::HSXKPasswd::RNG::RandomDorOrg->new('your.email@addre.ss');
);
The constructor must be called via the package name.
If called with no arguments the constructor will use an instance of
`Crypt::HSXKPasswd::Dictionary::EN' as the word source, the preset
`DEFAULT', and an instance of the class `Crypt::HSXKPasswd::RNG::Basic'
to generate random numbers.
The function accepts named arguments to allow for custom specification
of the word source, config, and random number source.
Specifying Custom Word Sources
Three named arguments can be used to specify a word source, but only one
should be specified at a time. If multiple are specified, the one with
the highest priority will be used, and the rest ignored. The variables
are listed below in descending order of priority:
* `dictionary' - an instance of a class that extends
`Crypt::HSXKPasswd::Dictionary'.
* `dictionary_list' - a reference to an array containing words as
scalars.
* `dictionary_file' - the path to a dictionary file. Dictionary files
should contain one word per. Lines starting with a # symbol will be
ignored. It is assumed files will be UTF-8 encoded. If not, a second
named argument, `dictionary_file_encoding', can be used to specify
another encoding.
Specifying Custom Password Generator Configurations
Two primary named arguments can be used to specify the config the
instance should use to generate passwords. Only one should be specified
at a time. If multiple are specified, the one with the highest priority
will be used, and the rest ignored. The variables are listed below in
descending order of priority:
* `config' - a valid config hashref.
* `config_json' - a JSON string representing a valid config hashref.
This named argument provides a convenient way to use configs
generated using the web interface at https://xkpasswd.net/. The
Save/Load tab in that interface saves and loads configs in JSON
format.
* `preset' - a valid preset name. If this variable is used, then any
desired config overrides can be passed as a hashref using the
variable `preset_overrides'.
Specifying Custom Random Number Generators
A custom RNG can be specified using the named argument `rng'. The passed
value must be an instance of a class that extends
`Crypt::HSXKPasswd::RNG' and overrides the function `random_numbers()'.
INSTANCE METHODS
NOTE - all instance methods must be invoked on a Crypt::HSXKPasswd
object or they will croak.
->config()
my $config = $hsxkpasswd_instance->config(); # getter
$hsxkpasswd_instance->config($config_hashref); # setter
$hsxkpasswd_instance->config($config_json_string); # setter
When called with no arguments the function returns a clone of the
instance's config hashref.
When called with a single argument the function sets the config of the
instance to a clone of the passed config. If present, the argument must
be either a hashref containing valid config keys and values, or a JSON
string representing a hashref containing valid config keys and values.
The function will croak if an invalid config is passed.
->config_as_json()
my $config_json_string = $hsxkpasswd_instance->config_as_json();
This function returns the content of the instance's loaded config
hashref as a JSON string.
The output from this function can be loaded into the web interface at
https://xkpasswd.net (using the load/save tab).
->config_as_string()
my $config_string = $hsxkpasswd_instance->config_as_string();
This function returns the content of the instance's loaded config
hashref as a scalar string.
->dictionary()
my $dictionary_clone = $hsxkpasswd_instance->dictionary();
$hsxkpasswd_instance->dictionary($dictionary_instance);
$hsxkpasswd_instance->dictionary($array_ref);
$hsxkpasswd_instance->dictionary('sample_dict_EN.txt');
$hsxkpasswd_instance->dictionary('sample_dict_EN.txt', 'Latin1');
When called with no arguments this function returns a clone of the
currently loaded dictionary which will be an instance of a class that
extends `Crypt::HSXKPasswd::Dictionary'.
To load a new dictionary into an instance, call this function with
arguments. The first argument argument can be an instance of a class
that extends `Crypt::HSXKPasswd::Dictionary', a reference to an array of
words, or the path to a dictionary file. If either an array reference or
a file path are passed, they will be used to instantiate an instance of
the class `Crypt::HSXKPasswd::Dictionary::Basic', and that new instance
will then be loaded into the object. If a file path is passed, it will
be assumed to be UTF-8 encoded. If not, an optional second argument can
be passed to specify the file's encoding.
->password()
my $password = $hsxkpasswd_instance->password();
This function generates a random password based on the instance's loaded
config and returns it as a scalar. The function takes no arguments.
The function croaks if there is an error generating the password. The
most likely cause of and error is the random number generation,
particularly if the loaded random generation function relies on a cloud
service or a non-standard library.
->passwords()
my @passwords = $hsxkpasswd_instance->passwords(10);
This function generates a number of passwords and returns them all as an
array.
The function uses `password()' to generate the passwords, and hence will
croak if there is an error generating any of the requested passwords.
->passwords_json()
my $json_string = $hsxkpasswd_instance->passwords_json(10);
This function generates a number of passwords and returns them and the
instance's entropy stats as a JSON string representing a hashref
containing an array of passwords indexed by `passwords', and a hashref
of entropy stats indexed by `stats'. The stats hashref itself is indexed
by: `password_entropy_blind', `password_permutations_blind',
`password_entropy_blind_min', `password_entropy_blind_max',
`password_permutations_blind_max', `password_entropy_seen' &
`password_permutations_seen'.
The function uses `passwords()' to generate the passwords, and hence
will croak if there is an error generating any of the requested
passwords.
->rng()
my $rng_instance = $hsxkpasswd_instance->rng();
$hsxkpasswd_instance->rng($rng_instance);
When called with no arguments this function returns currently loaded
Random Number Generator (RNG) which will be an instance of a class that
extends `Crypt::HSXKPasswd::RNG'.
To load a new RNG into an instance, call this function with a single
argument, an instance of a class that extends `Crypt::HSXKPasswd::RNG'.
->stats()
my %stats = $hsxkpasswd_instance->stats();
This function generates a hash containing stats about the instance
indexed by the following keys:
* `dictionary_contains_accents' - 1 if the filtered word list contains
accented letters, 0 otherwise.
* `dictionary_filter_length_min' & `dictionary_filter_length_max' -
the minimum and maximum word lengths allowed by the dictionary
filter (defined by config keys `word_length_min' and
`word_length_max')
* `dictionary_source' - the source of the word list loaded into the
instance.
* `dictionary_words_filtered' - the number of words loaded from the
dictionary file that meet the criteria defined by the loaded config.
* `dictionary_words_percent_available' - the percentage of the words
in the dictionary file that are available for use with the loaded
config.
* `dictionary_words_total' - the total number of words loaded from the
dictionary file.
* `password_entropy_blind_min' - the entropy (in bits) of the shortest
password the loaded config can generate from the point of view of a
brute-force attacker.
* `password_entropy_blind_max' - the entropy (in bits) of the longest
password the loaded config can generate from the point of view of a
brute-force attacker.
* `password_entropy_blind' - the entropy (in bits) of the average
length of passwords the loaded config can generate from the point of
view of a brute-force attacker.
* `password_entropy_seen' - the entropy (in bits) of passwords
generated by the instance assuming the dictionary and config are
known to the attacker.
* `password_length_min' - the minimum length of passwords generated by
the loaded config.
* `password_length_max' - the maximum length of passwords generated by
the loaded config.
* `password_permutations_blind_min' - the number of permutations a
brute-force attacker would have to try to be sure of cracking the
shortest possible passwords generated by this instance. Because this
number can be very big, it's returned as a `Math::BigInt' object.
* `password_permutations_blind_max' - the number of permutations a
brute-force attacker would have to try to be sure of cracking the
longest possible passwords generated by this instance. Because this
number can be very big, it's returned as a `Math::BigInt' object.
* `password_permutations_blind' - the number of permutations a
brute-force attacker would have to try to be sure of cracking an
average length password generated by this instance. Because this
number can be very big, it's returned as a `Math::BigInt' object.
* `password_permutations_seen' - the number of permutations an
attacker with a copy of the dictionary and config would need to try
to be sure of cracking a password generated by this instance.
Because this number can be very big, it's returned as a
`Math::BigInt' object.
* `passwords_generated' - the number of passwords this instance has
generated.
* `password_random_numbers_required' - the number of random numbers
needed to generate a single password using the loaded config.
* `randomnumbers_cached' - the number of random numbers currently
cached within the instance.
* `randomnumbers_cache_increment' - the number of random numbers
generated at once to replenish the cache when it's empty.
* `randomnumbers_source' - the class used by the instance to generate
random numbers.
->status()
print $hsxkpasswd_instance->status();
Generates a string detailing the internal status of the instance. Below
is a sample status string:
*DICTIONARY*
Source: Crypt::HSXKPasswd::Dictionary::EN
# words: 1425
# words of valid length: 1194 (84%)
*CONFIG*
case_transform: 'ALTERNATE'
num_words: '3'
padding_character: 'RANDOM'
padding_characters_after: '2'
padding_characters_before: '2'
padding_digits_after: '2'
padding_digits_before: '2'
padding_type: 'FIXED'
separator_alphabet: ['!', '$', '%', '&', '*', '+', '-', '.', '/', ':', ';', '=', '?', '@', '^', '_', '|', '~']
separator_character: 'RANDOM'
symbol_alphabet: ['!', '$', '%', '&', '*', '+', '-', '.', '/', ':', ';', '=', '?', '@', '^', '_', '|', '~']
word_length_max: '8'
word_length_min: '4'
*RANDOM NUMBER CACHE*
Random Number Generator: Crypt::HSXKPasswd::RNG::Basic
# in cache: 0
*PASSWORD STATISTICS*
Password length: between 24 & 36
Permutations (brute-force): between 2.91x10^47 & 1.57x10^71 (average 2.14x10^59)
Permutations (given dictionary & config): 5.51x10^15
Entropy (Brute-Force): between 157bits and 236bits (average 197bits)
Entropy (given dictionary & config): 52bits
# Random Numbers needed per-password: 9
Passwords Generated: 0
->update_config()
$hsxkpasswd_instance->update_config({separator_character => '+'});
The function updates the config within an HSXKPasswd instance. A hashref
with the config options to be changed must be passed. The function
returns a reference to the instance to enable function chaining. The
function will croak if the updated config would be invalid in some way.
Note that if this happens the running config will not have been altered
in any way.
CLASS METHODS
NOTE - All class methods must be invoked via the package name, or they
will croak.
clone_config()
my $clone = Crypt::HSXKPasswd->clone_config($config);
This function must be passed a valid config hashref as the first
argument or it will croak. The function returns a hashref.
config_key_definition()
my %key_definition = Crypt::HSXKPasswd->config_key_definition($key_name);
A function to return the definition for a config key. The definition is
returned as a hash indexed by the following keys:
* `required' - 1 if the key is a required key, and 0 otherwise.
* `type' - a `Type::Tiny' object representing the valid data type for
the key.
* `expects' - an English description of valid values for the key.
config_key_definitions()
my %key_definitions = Crypt::HSXKPasswd->config_key_definitions();
A function to return definitions for all defined config keys as a hash
indexed by config key names. Each definition is represented as a hash
with the same keys as the hashes returned by the function
`config_key_definition()'.
config_stats()
my %stats = Crypt::HSXKPasswd->config_stats($config);
my %stats = Crypt::HSXKPasswd->config_stats(
$config,
suppress_warnings => 1,
);
This function requires one argument, a valid config hashref. It returns
a hash of statistics about a given configuration. The hash is indexed by
the following:
* `length_min' - the minimum length a password generated with the
given config could be.
* `length_max' - the maximum length a password generated with the
given config could be. (see caveat below)
* `random_numbers_required' - the amount of random numbers needed to
generate a password using the given config.
There is one scenario in which the calculated maximum length will not be
reliably accurate, and that's when a character substitution with a
length greater than 1 is specified, and `padding_type' is not set to
`ADAPTIVE'. If the config passed contains such a character substitution,
the length will be calculated ignoring the possibility that one or more
extra characters could be introduced depending on how many, if any, of
the long substitutions get triggered by the randomly chosen words. If
this happens the function will also carp with a warning. Such warnings
can be suppressed by passing an optional named argument
`suppress_warnings' with the value `1'.
config_to_json()
my $config_json_string = Crypt::HSXKPasswd->config_to_json($config);
This function returns a JSON representation of the passed config hashref
as a scalar string.
The function must be passed a valid config hashref or it will croak.
config_to_string()
my $config_string = Crypt::HSXKPasswd->config_to_string($config);
This function returns the content of the passed config hashref as a
scalar string. The function must be passed a valid config hashref or it
will croak.
default_config()
my $config = Crypt::HSXKPasswd->default_config();
This function returns a hashref containing a config with default values.
This function can optionally be called with a single argument, a hashref
containing keys with values to override the defaults with.
my $config = Crypt::HSXKPasswd->default_config({num_words => 3});
When overrides are present, the function will carp if an invalid key or
value is passed, and croak if the resulting merged config is invalid.
This function is a shortcut for `preset_config()', and the two examples
above are equivalent to the following:
my $config = Crypt::HSXKPasswd->preset_config('DEFAULT');
my $config = Crypt::HSXKPasswd->preset_config('DEFAULT', {num_words => 3});
defined_config_keys()
my @config_key_names = Crypt::HSXKPasswd->defined_config_keys();
This function returns the list of valid config key names as an array of
strings.
defined_presets()
my @preset_names = Crypt::HSXKPasswd->defined_presets();
This function returns the list of defined preset names as an array of
strings.
distil_to_config_keys()
my $dist_hashref = Crypt::HSXKPasswd->distil_to_config_keys($hashref);
This function takes a hashref as an argument, and returns a deep clone
of that hashref containing only valid config keys with valid values.
By default the function silently drops keys that are not valid config
keys, but issues a warning when dropping a key that is a valid config
key, but contains an invalid value. The function can also issue warnings
when dropping keys that are not valid config keys.
The warnings can be controlled with a pair of optional named arguments
that can be added as a second argument:
# suppress all warnings
my $dist_hashref = Crypt::HSXKPasswd->distil_to_config_keys(
$hashref,
suppress_warnings => 1,
);
# emit warnings when dropping invalidly named keys
my $dist_hashref = Crypt::HSXKPasswd->distil_to_config_keys(
$hashref,
warn_invalid_key_names => 1,
);
distil_to_symbol_alphabet()
my @unique_syms = Crypt::HSXKPasswd->distil_to_symbol_alphabet($arrayref);
my @unique_syms = Crypt::HSXKPasswd->distil_to_symbol_alphabet(
$arrayref,
warn => 1,
);
This function takes reference to an array of strings and returns a new
array containing all the valid symbols from the referenced array. The
valid symbols are de-duplicated before being returned.
By default the function silently skips over strings that are not valid
symbols. The function can be made issue warnings each time a string is
skipped by passing a named argument `warn' with a value of `1' (`0' can
also be passed to explicitly disable warnings).
distil_to_words()
my @valid_unique_words = Crypt::HSXKPasswd->distil_to_words($arrayref);
my @valid_unique_words = Crypt::HSXKPasswd->distil_to_words(
$arrayref,
warn => 1,
);
This function takes reference to an array of strings and returns a new
array containing all the valid words from the referenced array. The
valid words are de-duplicated before being returned.
By default the function silently skips over strings that are not valid
words. The function can be made issue warnings each time a string is
skipped by passing a named argument `warn' with a value of `1' (`0' can
also be passed to explicitly disable warnings).
is_valid_config()
# determine the validity
my $is_ok = Crypt::HSXKPasswd->is_valid_config($config);
# assert the validity - will croak if the config is invalid
Crypt::HSXKPasswd->is_valid_config($config, croak => 1);
This function must be passed a hashref to test as the first argument.
The function returns 1 if the passed config is valid, and 0 otherwise.
Optionally, a named argument `croak' can also be passed to control
whether or not the function should croak if the config is invalid. The
value of this named argument should be `1' or `0'.
When calling the function with `croak' set to `1', the message thrown by
croak will explain why the config is invalid.
use English qw( -no_match_vars );
eval{
Crypt::HSXKPasswd->is_valid_config($config, croak => 1);
}or do{
print "ERROR - config is invalid because: $EVAL_ERROR\n";
}
module_config()
my $debug_val = Crypt::HSXKPasswd->module_config('DEBUG'); # getter
Crypt::HSXKPasswd->module_config('DEBUG', 1); # setter
This function is used to access or alter the value of one of the module
configuration settings. The first function must always be a valid module
configuration key name. If no second argument is provided, the value
stored in the module configuration key will not be updated. To update
the stored value, pass a new value as a second argument. Regardless of
whether or not a second argument is passed, the value stored in the
module configuration key is always returned.
The function will croak if called with an invalid module configuration
key name, or passed an invalid new value.
For a list of the module configuration keys, see the MODULE
CONFIGURATION section of this document.
preset_config()
my $config = Crypt::HSXKPasswd->preset_config('XKCD');
This function returns the config hashref for a given preset. See above
for the list of available presets.
The first argument this function accepts is the name of the desired
preset as a scalar. If an invalid name is passed, the function will
carp. If no preset is passed the preset `DEFAULT' is assumed.
This function can optionally accept a second argument, a hashref
containing keys with values to override the defaults with.
my $config = Crypt::HSXKPasswd->preset_config(
'XKCD',
{case_transform => 'INVERT'}
);
When overrides are present, the function will carp if an invalid key or
value is passed, and croak if the resulting merged config is invalid.
preset_definition()
my %preset_def = Crypt::HSXKPasswd->preset_definition('XKCD');
This function returns a hash defining a preset. The hash contains an
English description of the preset indexed be `description' and a config
hashref indexed by `config'.
The function expects to be called with one argument, a valid preset
name, but it can be called without arguments, in which case it will
return the definition for the preset c<DEFAULT>.
You can see all the defined presets in the PRESETS section of this
document, and you can get a list of valid preset names programatically
with the function `defined_presets()'.
preset_definitions()
my %preset_defs = Crypt::HSXKPasswd->preset_definitions();
This function returns a hash of all defined presets indexed by preset
name. Each preset definition is a hash as returned by
`preset_definition()'.
This function does not take any arguments.
presets_json()
my $json_string = Crypt::HSXKPasswd->presets_json();
This function returns a JSON string representing all the defined
configs, including their descriptions.
The returned JSON string represents a hashref indexed by three keys:
`defined_keys' contains an array of preset identifiers, `presets'
contains the preset configs indexed by reset identifier, and
`preset_descriptions' contains a hashref of descriptions indexed by
preset identifiers.
preset_description()
my $description = Crypt::HSXKPasswd->preset_description('XKCD');
This function returns the description for a given preset. See above for
the list of available presets.
The first argument this function accepts is the name of the desired
preset as a scalar. If an invalid name is passed, the function will
carp. If no preset is passed the preset `DEFAULT' is assumed.
presets_to_string()
print Crypt::HSXKPasswd->presets_to_string();
This function returns a string containing a description of each defined
preset and the configs associated with the presets.
COMMANDLINE INTERFACE
The module ships with a commandline interface to this library, simply
called `hsxkpasswd'.
This interface allows for the generation of multiple passwords at a
time, the use of presets and preset overrides, the use of custom
password generator configurations, the use of custom word sources, and
the use of custom random number generators.
Both preset overrides and password generator configurations must be
specified in JSON format.
Examples
Generate a single password using all the default settings:
hsxkpasswd
Generate five passwords using the default settings:
hsxkpasswd 5
Generate five passwords using the `XKCD' preset:
hsxkpasswd -p XKCD 5
Generate five passwords using the `XKCD' preset with an overridden
password generator configuration key:
hsxkpasswd -p XKCD -o '{"separator_character" : "*"}' 5
Generate five passwords using a custom password generator configuration
stored in a text file in JSON format:
hsxkpasswd -c my_config.json
Further Reading
The examples above are just a sample of what the command can do, for
complete documentation, run the command with the -h flag:
hsxkpasswd -h
If you are new to JSON, you may find the following links useful:
* JSON on Wikipedia - http://en.wikipedia.org/wiki/JSON
* A free online JSON validator -
http://jsonformatter.curiousconcept.com
* A JSON tutorial from W3Schools - http://www.w3schools.com/json/
ENTROPY CHECKING
For security reasons, this module's default behaviour is to warn (using
`carp()') when ever the loaded combination of word source and
configuration would result in low-entropy passwords. When the
constructor is invoked, or when an instance's the word source or config
are altered (using `dictionary()' or `config()'), the entropy is
re-calculated and re-checked against the defined minima.
Entropy is calculated and checked for two scenarios. Firstly, for the
best-case scenario, when an attacker has no prior knowledge about the
password, and must resort to a brute-force attack. And secondly, for the
worst-case scenario, when the attacker is assumed to know that this
module was used to generate the password, and, that the attacker has a
copy of the word source and config settings used to generate the
password.
Entropy checking is controlled via three module configuration variables
(which can be accessed and updated using the function
`module_config()'):
* `ENTROPY_MIN_BLIND' - the minimum acceptable entropy in bits for a
brute-force attack. The default value is 78bits, the equivalent to a
12 character password consisting of mixed-case letters, digits, and
symbols.
* `ENTROPY_MIN_SEEN' - the minimum acceptable entropy in bits for a
worst-case scenario (where the word source and config are known).
The default value is 52bits, equivalent to an 8 character password
consisting of mixed-case letters, digits, and symbols.
* `ENTROPY_WARNINGS' - this variable can be used to control the
emission of entropy warnings. The following values are valid:
* `ALL' - all entropy warnings are emitted. This is the default
value.
* `BLIND' - only warnings for the best-case scenario are emitted.
I.e. warnings for the worst-case scenario (attacker has full
knowledge) are suppressed.
* `NONE' - all entropy warnings are suppressed.
Caveats
The entropy calculations make some assumptions which may in some cases
lead to the results being inaccurate. In general, an attempt has been
made to always round down, meaning that in reality the entropy of the
produced passwords may be higher than the values calculated by the
package.
When calculating the entropy for brute force attacks on configurations
that can result in variable length passwords, the shortest possible
password is assumed.
When calculating the entropy for brute force attacks on configurations
that contain at least one symbol, it is assumed that an attacker would
have to brute-force-check 33 symbols. This is the same value used by
Steve Gibson's *Password Haystacks* calculator
(https://www.grc.com/haystack.htm).
When calculating the entropy for worst-case attacks on configurations
that contain symbol substitutions where the replacement is more than 1
character long the possible extra length is ignored.
WORD SOURCES (DICTIONARIES)
The abstract class `Crypt::HSXKPasswd::Dictionary' acts as a base class
for sources of words for use by this module. Word sources should extend
this base class and implement the function `word_list()', which should
return an array of words.
In order to produce secure passwords it's important to use a word source
that contains a large selection of words with a good mix of different
lengths of words.
The module ships with a number of pre-defined word sources:
`Crypt::HSXKPasswd::Dictionary::DE'
A German word list based on the GPL-licensed German dictionary for
WinEdit by Juergen Vierheilig.
Note: This module is licensed under the GPL, not the BSD license used
for the majority of this project.
`Crypt::HSXKPasswd::Dictionary::EN'
A default word list consisting of English words and place names.
`Crypt::HSXKPasswd::Dictionary::ES'
A Spanish word list based on the BSD-licensed Spanish dictionary for
WinEdit by Juan L. Varona from the Universidad de La Rioja.
`Crypt::HSXKPasswd::Dictionary::FR'
A French word list based on the GPL-licensed French dictionary for
WinEdit.
Note: This module is licensed under GPL V2, not the BSD license used for
the majority of this project.
`Crypt::HSXKPasswd::Dictionary::IT'
An Italian word list based on the free-for-non-commerical-use Italian
dictionary for WinEdit by Karl Koeller.
Note: This module is licensed under GPL V2, not the BSD license used for
the majority of this project.
`Crypt::HSXKPasswd::Dictionary::NL'
A Dutch/Flemish word list based on the GPL-licensed Dutch dictionary for
WinEdit.
Note: This module is licensed under GPL V2, not the BSD license used for
the majority of this project.
`Crypt::HSXKPasswd::Dictionary::PT'
A Portuguese word list based on the GPL-licensed Portuguese dictionary
for WinEdit compiled by Bernhard Enders (building on work by Raimundo
Santos Moura & Ricardo Ueda Karpischek).
Note: This module is licensed under GPL V2.1, not the BSD license used
for the majority of this project.
`Crypt::HSXKPasswd::Dictionary::System'
This class tries to find and use a Unix words file on the system.
The constructor croaks if no system words file can be found.
Usage
my $word_source = Crypt::HSXKPasswd::Dictionary::System->new();
`Crypt::HSXKPasswd::Dictionary::Basic'
This class can be initialised from a words file, or from an array ref
containing words.
Usage
my $word_source = Crypt::HSXKPasswd::Dictionary::Basic->new('file_path');
my $word_source = Crypt::HSXKPasswd::Dictionary::Basic->new(
'file_path',
'Latin1'
);
my $word_source = Crypt::HSXKPasswd::Dictionary::Basic->new($array_ref);
The rules for the formatting of dictionary files are simple. Dictionary
files must contain one word per line. Words shorter than four letters
will be ignored, as will all lines starting with the # symbol. Files are
assumed to be UTF-8 encoded, but an optional second argument can be
passed specifying a different file encoding.
This format is the same as that of the standard Unix Words file, usually
found at `/usr/share/dict/words' on Unix and Linux operating systems
(including OS X).
RANDOM NUMBER SOURCES
In order to minimise the number of non-standard modules this module
requires, the default source of randomness is Perl's built-in `rand()'
function. This provides a reasonable level of randomness, and should
suffice for most users, however, some users will prefer to make use of
one of the many advanced randomisation modules in CPAN, or, reach out to
a web service like http://random.org for their random numbers. To
facilitate both of these options, this module uses a cache of
randomness, and provides an abstract Random Number Generator (RNG) class
that can be extended.
The module can use an instance of any class that extends
`Crypt::HSXKPasswd::RNG' as it's source of randomness. Custom RNG
classes must implement the method `random_numbers()' which will be
invoked on an instance of the class and passed one argument, the number
of random numbers required to generate a single password. The function
must return an array of random numbers between 0 and 1. The number of
random numbers returned is entirely up to the module to decide. The
number required for a single password is passed purely as a guide. The
function must always return at least one random number.
The module ships with five standard RNGs (described below).
By default, the module will try to use one of the following four RNGs,
listed from most to least preferred, depending on what is available on
the system:
1 `Crypt::HSXKPasswd::RNG::Math_Random_Secure' (only available if
`Math::Random::Secure' is installed on the system).
2 `Crypt::HSXKPasswd::RNG::Data_Entropy' (only available if
`Data::Entropy::Algorithms' is installed on the system).
3 `Crypt::HSXKPasswd::RNG::DevUrandom' (only available on Linux/Unix
systems with a `/dev/urandom').
4 `Crypt::HSXKPasswd::RNG::Basic' (available on all systems because it
uses Perl's built-in `rand()' function).
If the constructor is called without specifying an RNG, and if the only
available RNG is `Crypt::HSXKPasswd::RNG::Basic', a warning will be
thrown suggesting installing `Math::Random::Secure' or
`Data::Entropy::Algorithms'.
The module also ships with a fifth RNG,
`Crypt::HSXKPasswd::RNG::RandomDotOrg', but this one must be explicitly
used, the constructor will never used it by default. As its name
suggests, this class uses http://Random.Org/'s HTTP API to generate
random numbers.
To explicitly use any particular RNG, create an instance of it, and
either pass that instance to the constructor with the named argument
`rng', or, set the RNG after instantiating the object using the `rng()'
function.
Crypt::HSXKPasswd::RNG::Math_Random_Secure
my $rng = Crypt::HSXKPasswd::RNG::Math_Random_Secure->new();
This is the preferred RNG because it is both fast and secure, but, it
requires the non-standard module `Math::Random::Secure'
(http://search.cpan.org/perldoc?Math%3A%3ARandom%3A%3ASecure) be
installed.
Crypt::HSXKPasswd::RNG::Data_Entropy
my $rng = Crypt::HSXKPasswd::RNG::Data_Entropy->new();
This RNG is secure, but it is quite slow (about six times slower than
`Crypt::HSXKPasswd::RNG::Math_Random_Secure'), and it requires the
non-standard module `Data::Entropy::Algorithms'
(http://search.cpan.org/perldoc?Data%3A%3AEntropy%3A%3AAlgorithms) be
installed.
Crypt::HSXKPasswd::RNG::DevUrandom
my $rng = Crypt::HSXKPasswd::RNG::DevUrandom->new();
This RNG is secure and relatively fast (faster than
`Crypt::HSXKPasswd::RNG::Data_Entropy' but slower than
`Crypt::HSXKPasswd::RNG::Math_Random_Secure'), but is only available on
Linux/Unix systems with a `/dev/urandom' special file.
Crypt::HSXKPasswd::RNG::Basic
my $rng = Crypt::HSXKPasswd::RNG::Basic->new();
This RNG uses Perl's built-in `rand()' function as its source of
randomness, and this is sub-optimal. The Perl docs warn that `rand()' is
not a particularly good source of random numbers, and advises against
its use for cryptography.
This RNG provides a base-line, and should only be used if none of the
better RNGs are available. While it is sub-optimal, it will still
generate passwords with sufficient entropy in most situations.
Ultimately, even using this imperfect RNG, this module will still
produce passwords that are much better than those produced by the human
imagination!
Crypt::HSXKPasswd::RNG::RandomDotOrg
my $rng = Crypt::HSXKPasswd::RNG::RandomDotOrg->new('my.address@my.dom');
my $rng = Crypt::HSXKPasswd::RNG::RandomDotOrg->new('my.address@my.dom',
timeout => 180,
num_passwords => 3,
);
This RNG serves as a usable example of an RNG that queries a web
service. As its name suggests, this class uses http://Random.Org/'s HTTP
API to generate random numbers.
In order to comply with Random.Org's client guidelines
(https://www.random.org/clients/), this module requires that a valid
email address be passed as the first argument.
The client guidelines also request that clients use long timeouts, and
batch their requests. They prefer to be asked for more number less
frequently than less numbers more frequently. For this reason the
class's default behaviour is to use a timeout of 180 seconds, and to
request enough random numbers to generate three passwords at a time.
These defaults can be overridden by passing named arguments to the
constructor after the email address. The following named arguments are
supported:
* `timeout' - the timeout to use when making HTTP requests to
Random.Org in seconds (the default is 180).
* `num_passwords' - the number of password generations to fetch random
numbers for per request from Random.org. This value is in effect a
multiplier for the value passed to the `random_numbers()' function
by `Crypt::HSXKPasswd'.
`num_absolute' - the absolute number of random numbers to fetch per
request to Random.Org. This argument takes precedence over
`num_passwords'.
`num_passwords' and `num_absolute' should not be used together, but if
they are, `num_absolute' use used, and `num_passwords' is ignored.
This class requires a number of modules not used by any other classes
under `Crypt::HSXKPasswd', and not listed in that module's requirements.
If all of the following modules are not installed, the constructor will
croak:
* `Email::Valid'
* `LWP::UserAgent'
* `Mozilla::CA'
* `URI'
DIAGNOSTICS
By default this module does all of it's error notification via the
functions `carp()', `croak()', and `confess()' from the `Carp' module.
Optionally, all error messages can also be printed to a stream. To
enable the printing of messages, set the `LOG_ERRORS' module
configuration variable to `1'. All error messages will then be printed
to the stream defined by the module configuration variable `LOG_STREAM',
which is set to `STDERR' by default.
Ordinarily this module produces very little output. To enable more
verbose output the module configuration variable `DEBUG' can be set to
`1'. Debug message are printed to the stream specified by the module
variable `LOG_STREAM'.
This module produces output at three severity levels:
* `DEBUG' - this output is completely suppressed unless the module
configuration variable `DEBUG' is set to `1'. All debug messages are
printed to the stream defined in the module configuration variable
`LOG_STREAM' (regardless of the the value of the module
configuration variable `LOG_ERRORS').
* `WARNING' - warning messages are always thrown with `carp()', and
also printed to the stream specified by the module configuration
variable `LOG_STREAM' if the module configuration variable
`LOG_ERRORS' is set to `1'.
* `ERROR' - error messages are usually thrown with `croak()', but will
be thrown with `confess()' if the module configuration variable
`DEBUG' is set to `1'. If the module configuration variable
`LOG_ERRORS' is set to `1' errors are also printed to the stream
defined by the module configuration variable `LOG_STREAM', including
a stack trace if the module configuration variable `DEBUG' is set to
`1' and the module `Devel::StackTrace' is installed.
The value stored in a module configuration variable can be accessed and
updated using the function `module_config()'.
CONFIGURATION AND ENVIRONMENT
This module does not currently support configuration files, nor does it
currently interact with the environment. It may do so in future
versions.
DEPENDENCIES
This module requires the following Perl modules:
* `Carp' - http://search.cpan.org/perldoc?Carp
* `Clone' - http://search.cpan.org/perldoc?Clone
* `DateTime' - http://search.cpan.org/perldoc?DateTime
* `English' - http://search.cpan.org/perldoc?English
* `Fatal' - http://search.cpan.org/perldoc?Fatal
* `File::HomeDir' - http://search.cpan.org/perldoc?File%3A%3AHomeDir
* `Getopt::Long' - http://search.cpan.org/perldoc?Getopt%3A%3ALong
* `JSON' - http://search.cpan.org/perldoc?JSON
* `List::MoreUtils' -
http://search.cpan.org/perldoc?List%3A%3AMoreUtils
* `Math::BigInt' - http://search.cpan.org/perldoc?Math%3A%3ABigInt
* `Math::Round' - http://search.cpan.org/perldoc?Math%3A%3ARound
* `Module::Load' - http://search.cpan.org/perldoc?Module%3A%3ALoad
* `Pod::Usage' - http://search.cpan.org/perldoc?Pod%3A%3AUsage
* `Readonly' - http://search.cpan.org/perldoc?Readonly
* `Scalar::Util' - http://search.cpan.org/perldoc?Scalar%3A%3AUtil
* `strict' - http://search.cpan.org/perldoc?strict
* `Text::Unidecode' -
http://search.cpan.org/perldoc?Text%3A%3AUnidecode
* `Type::Library' - http://search.cpan.org/perldoc?Type%3A%3ALibrary
* `Type::Params' - http://search.cpan.org/perldoc?Type%3A%3AParams
* `Type::Tiny' - http://search.cpan.org/perldoc?Type%3A%3ATiny
* `Types::Standard' -
http://search.cpan.org/perldoc?Types%3A%3AStandard
* `warnings' - http://search.cpan.org/perldoc?warnings
The module can also optionally use the following Perl modules:
* `Data::Entropy::Algorithms' -
http://search.cpan.org/perldoc?Data%3A%3AEntropy%3A%3AAlgorithms
Used by the RNG class `Crypt::HSXKPasswd::RNG::Data_Entropy'.
* `Devel::StackTrace' -
http://search.cpan.org/perldoc?Devel%3A%3AStackTrace
Used for printing stack traces with error messages if
`$XKPasswd::DEBUG' and `$XKPasswd::LOG_ERRORS' both evaluate to
true. If the module is not installed the stack traces will be
omitted from the log messages.
* `Email::Valid' - http://search.cpan.org/perldoc?Email%3A%3AValid
Used by the Random.Org RNG class
`Crypt::HSXKPasswd::RNG::RandomDotOrg'.
* `LWP::UserAgent' - http://search.cpan.org/perldoc?LWP%3A%3AUserAgent
Used by the Random.Org RNG class
`Crypt::HSXKPasswd::RNG::RandomDotOrg'.
* `Math::Random::Secure' -
http://search.cpan.org/perldoc?Math%3A%3ARandom%3A%3ASecure
Used by the RNG class `Crypt::HSXKPasswd::RNG::Math_Random_Secure'.
* `Mozilla::CA' - http://search.cpan.org/perldoc?Mozilla%3A%3ACA
Indirectly required by the Random.Org RNG class
`Crypt::HSXKPasswd::RNG::RandomDotOrg' because without it
`LWP::UserAgent' can't use HTTPS, and the Random.Org API uses HTTPS.
* `URI' - http://search.cpan.org/perldoc?URI
Used by the Random.Org RNG class
`Crypt::HSXKPasswd::RNG::RandomDotOrg'.
INCOMPATIBILITIES
This module has no known incompatibilities.
BUGS AND LIMITATIONS
There are no known bugs in this module.
Please report any bugs you may find on the module's GitHub page:
https://github.com/bbusschots/xkpasswd.pm.
LICENCE AND COPYRIGHT
Copyright (c) 2014-15, Bart Busschots T/A Bartificer Web Solutions All
rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
The following components of this package are covered by the more
restrictive GPL V2 license https://www.gnu.org/licenses/gpl-2.0.html:
* The `share/sample_dict_DE.txt' text file.
* The `Crypt::HSXKPasswd::Dictionary::DE' Perl module.
* The `share/sample_dict_FR.txt' text file.
* The `Crypt::HSXKPasswd::Dictionary::FR' Perl module.
* The `share/sample_dict_IT.txt' text file.
* The `Crypt::HSXKPasswd::Dictionary::IT' Perl module.
* The `share/sample_dict_NL.txt' text file.
* The `Crypt::HSXKPasswd::Dictionary::NL' Perl module.
* The `share/sample_dict_PT.txt' text file.
* The `Crypt::HSXKPasswd::Dictionary::PT' Perl module.
AUTHOR
Bart Busschots (mailto:bart@bartificer.net)