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);
   $octets = random_bytes(45);
   $hex_string = random_bytes_hex(45);
   $base64_string = random_bytes_b64(45);
   $base64url_string = random_bytes_b64u(45);
   $alphanumeric_string = random_string(30);
   $string = random_string_from('ACGT', 64);
   $floating_point_number_0_to_1 = rand;
   $floating_point_number_0_to_88 = rand(88);
   $unsigned_32bit_int = irand;
   ### OO interface:
   use Crypt::PRNG;
   $prng = Crypt::PRNG->new;  # defaults to ChaCha20
   #or
   $prng = Crypt::PRNG->new("RC4");
   #or
   $prng = Crypt::PRNG->new("RC4", "some data used for seeding PRNG");
   $octets = $prng->bytes(45);
   $hex_string = $prng->bytes_hex(45);
   $base64_string = $prng->bytes_b64(45);
   $base64url_string = $prng->bytes_b64u(45);
   $alphanumeric_string = $prng->string(30);
   $string = $prng->string_from('ACGT', 64);
   $floating_point_number_0_to_1 = $prng->double;
   $floating_point_number_0_to_88 = $prng->double(88);
   $unsigned_32bit_int = $prng->int32;

DESCRIPTION

Provides an interface to the ChaCha20 based pseudo random number generator (thread-safe and fork-safe).

FUNCTIONS

random_bytes

   $octets = random_bytes($length);

Returns $length random octects.

random_bytes_hex

   $hex_string = random_bytes_hex($length);

Returns $length random octects encoded as hexadecimal string.

random_bytes_b64

   $base64_string = random_bytes_b64($length);

Returns $length random octects Base64 encoded.

random_bytes_b64u

   $base64url_string = random_bytes_b64u($length);

Returns $length random octects Base64 URL Safe (RFC 4648 section 5) encoded.

random_string_from

   $string = random_string_from($range, $length);
   #e.g.
   $string = random_string_from("ABCD", 10);

Returns a random string made of $length chars randomly chosen from $range string.

random_string

   $alphanumeric_string = random_string($length);
   #or
   $alphanumeric_string = random_string;  # default length = 20

Similar to random_string_from, only $range is fixed to 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'.

rand

   $n = rand;
   #or
   $n = rand($limit);

Returns a random floating point number from range "[0,1)" (if called without parameter) or "[0,$limit)".

irand

   $i = irand;

Returns a random unsigned 32bit integer - range "0 .. 0xFFFFFFFF".

METHODS

new

   $prng = Crypt::PRNG->new;  # defaults to ChaCha20
   #or
   $prng = Crypt::PRNG->new($alg);
   #or
   $prng = Crypt::PRNG->new($alg, $seed);
   # $alg  ... algorithm name 'ChaCha20' (DEFAULT), 'Fortuna', 'RC4', 'Sober128' or 'Yarrow'
   # $seed ... will be used as an initial entropy for seeding PRNG

If $seed is not specified the PRNG is automatically seeded with 32bytes random data taken from "/dev/random" (UNIX) or "CryptGenRandom" (Win32)

add_entropy

  $prng->add_entropy($random_data);
  #or
  $prng->add_entropy();

If called without parameter it uses 32bytes random data taken from "/dev/random" (UNIX) or "CryptGenRandom" (Win32).

BEWARE: you probably do not need this function at all as the module does automatic seeding on initialization as well as reseeding after fork and thread creation.

bytes

   $octets = $prng->bytes($length);

See random_bytes

bytes_hex

   $hex_string = $prng->bytes_hex($length);

See random_bytes_hex

bytes_b64

   $base64_string = $prng->bytes_b64($length);

See random_bytes_b64

bytes_b64u

   $base64url_string = $prng->bytes_b64u($length);

See random_bytes_b64u

string

   $alphanumeric_string = $prng->string($length);
   #or
   $alphanumeric_string = $prng->string;

See random_string

string_from

   $string = $prng->string_from($range, $length);

See random_string_from

double

   $n = $prng->double;
   #or
   $n = $prng->double($limit);

See rand

int32

   $i = $prng->int32;

See irand