NAME
Crypt::PRNG - Cryptographically secure random number generator
SYNOPSIS
### Functional interface:
use Crypt::PRNG qw(random_bytes random_bytes_hex random_bytes_b64 random_bytes_b64u
random_string random_string_from rand irand);
my $octets = random_bytes(45);
my $hex_string = random_bytes_hex(45);
my $base64_string = random_bytes_b64(45);
my $base64url_string = random_bytes_b64u(45);
my $alphanumeric_string = random_string(30);
my $string = random_string_from('ACGT', 64);
my $floating_point_number_0_to_1 = rand;
my $floating_point_number_0_to_88 = rand(88);
my $unsigned_32bit_int = irand;
### OO interface:
use Crypt::PRNG;
my $prng = Crypt::PRNG->new; # defaults to ChaCha20
my $rc4_prng = Crypt::PRNG->new("RC4");
my $seeded_prng = Crypt::PRNG->new("RC4", "some data used for seeding PRNG");
my $octets = $prng->bytes(45);
my $hex_string = $prng->bytes_hex(45);
my $base64_string = $prng->bytes_b64(45);
my $base64url_string = $prng->bytes_b64u(45);
my $alphanumeric_string = $prng->string(30);
my $string = $prng->string_from('ACGT', 64);
my $floating_point_number_0_to_1 = $prng->double;
my $floating_point_number_0_to_88 = $prng->double(88);
my $unsigned_32bit_int = $prng->int32;DESCRIPTION
Provides an interface to several pseudo-random number generators (thread-safe and fork-safe). The default algorithm is ChaCha20.
EXPORT
Nothing is exported by default.
You can export selected functions:
use Crypt::PRNG qw(random_bytes random_string);Or all of them at once:
use Crypt::PRNG ':all';FUNCTIONS
For all random_bytes* functions and the corresponding bytes* methods, $length must not be greater than 1000000000.
random_bytes
my $octets = random_bytes($length);
# $length .. [integer] number of random bytes to generateReturns $length random octets as a binary string.
random_bytes_hex
my $hex_string = random_bytes_hex($length);
# $length .. [integer] number of random bytes (output string will be 2x longer)Returns $length random octets encoded as a lowercase hexadecimal string.
random_bytes_b64
my $base64_string = random_bytes_b64($length);
# $length .. [integer] number of random bytes to encodeReturns $length random octets encoded as a Base64 string.
random_bytes_b64u
my $base64url_string = random_bytes_b64u($length);
# $length .. [integer] number of random bytes to encodeReturns $length random octets encoded as a Base64 URL-safe string (RFC 4648 section 5).
random_string_from
my $string = random_string_from($range, $length);
# $range .. [string] alphabet of allowed characters
# $length .. [integer] optional, number of characters (DEFAULT: 20)
#e.g.
my $dna_string = random_string_from("ABCD", 10);Returns a random string of $length characters chosen from $range. The alphabet must contain between 1 and 65536 characters; longer alphabets return undef.
random_string
my $alphanumeric_string = random_string($length);
# $length .. [integer] optional, number of characters (DEFAULT: 20)
#or
my $default_alphanumeric_string = random_string; # default length = 20Like random_string_from, but $range is fixed to 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'.
rand
my $n = rand;
#or
my $limited_n = rand($limit);
# $limit .. [number] optional, upper bound (exclusive)Returns a random floating-point number in the range [0,1) if called without an argument, or [0,$limit) if $limit is given. If $limit is 0, this behaves as if no limit was given and returns a value in [0,1), matching Perl's built-in rand.
irand
my $i = irand;Returns a random unsigned 32-bit integer in the range 0 .. 0xFFFFFFFF.
METHODS
Unless noted otherwise, assume $prng is an existing PRNG object created via new, for example:
my $prng = Crypt::PRNG->new;new
my $prng = Crypt::PRNG->new; # defaults to ChaCha20
#or
my $prng = Crypt::PRNG->new($alg);
#or
my $prng = Crypt::PRNG->new($alg, $seed);
# $alg ... [string] algorithm name: 'ChaCha20' (DEFAULT), 'Fortuna', 'RC4' (legacy; compatibility only), 'Sober128' or 'Yarrow'
# $seed ... [binary string] optional, initial entropy for seeding the PRNGIf $seed is not given, the PRNG is automatically seeded with 40 bytes obtained via libtomcrypt's rng_get_bytes() platform RNG logic.
If $seed is specified it must be non-empty for all algorithms. RC4 is provided for legacy compatibility only, is not recommended for new designs, and requires a seed of at least 5 bytes.
add_entropy
my $prng = Crypt::PRNG->new;
$prng->add_entropy($random_data);
#or
$prng->add_entropy();If called without parameter it uses 40 bytes obtained via libtomcrypt's rng_get_bytes() platform RNG logic.
Note: You probably do not need this function. The module seeds itself on initialization and reseeds after fork and thread creation.
bytes
my $octets = $prng->bytes($length);See random_bytes
bytes_hex
my $hex_string = $prng->bytes_hex($length);See random_bytes_hex
bytes_b64
my $base64_string = $prng->bytes_b64($length);See random_bytes_b64
bytes_b64u
my $base64url_string = $prng->bytes_b64u($length);string
my $alphanumeric_string = $prng->string($length);
#or
my $default_alphanumeric_string = $prng->string; # default length = 20See random_string
string_from
my $string = $prng->string_from($range, $length); # default length = 20double
my $n = $prng->double;
#or
my $limited_n = $prng->double($limit);See rand
int32
my $i = $prng->int32;See irand
SEE ALSO
Crypt::PRNG::ChaCha20, Crypt::PRNG::Fortuna, Crypt::PRNG::RC4, Crypt::PRNG::Sober128, Crypt::PRNG::Yarrow
For generating random UUIDs see "random_v4uuid" in Crypt::Misc and "random_v7uuid" in Crypt::Misc.