# Crypt::PRNG - phpMan

## 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;
       #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;
       #or
       $prng = [Crypt::PRNG]->new($alg);
       #or
       $prng = [Crypt::PRNG]->new($alg, $seed);

       # $alg  ... algorithm name 'Frotuna' (DEFAULT), '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

## SEE ALSO
    [Crypt::PRNG::Fortuna], [Crypt::PRNG::RC4], [Crypt::PRNG::Sober128],
    [Crypt::PRNG::Yarrow]