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📖 NAME

Crypt::OpenSSL::Random - OpenSSL/LibreSSL pseudo-random number generator access

🚀 Quick Reference

Use Case	Command	Description
Seed PRNG with random data	Crypt::OpenSSL::Random::random_seed($data)	🌱 Seeds the PRNG with a string of bytes; returns true if sufficient seeding.
Seed PRNG from EGD daemon	Crypt::OpenSSL::Random::random_egd("/path")	🔌 Seeds from entropy gathering daemon; returns bytes read or -1. (Not on LibreSSL)
Check PRNG seeding status	Crypt::OpenSSL::Random::random_status()	✅ Returns true if PRNG has sufficient seeding.
Get cryptographically strong random bytes	Crypt::OpenSSL::Random::random_bytes(10)	🔒 Returns 10 strong random bytes, or false if insufficient seed.
Get pseudo-random bytes (non-cryptographic)	Crypt::OpenSSL::Random::random_pseudo_bytes(10)	🔓 Returns 10 pseudo-random bytes (not necessarily unpredictable).

📋 SYNOPSIS

use Crypt::OpenSSL::Random;

Crypt::OpenSSL::Random::random_seed($good_random_data);
Crypt::OpenSSL::Random::random_egd("/tmp/entropy");
Crypt::OpenSSL::Random::random_status() or
  die "Unable to sufficiently seed the random number generator".

my $ten_good_random_bytes = Crypt::OpenSSL::Random::random_bytes(10);
my $ten_ok_random_bytes = Crypt::OpenSSL::Random::random_pseudo_bytes(10);

🔍 DESCRIPTION

Crypt::OpenSSL::Random provides the ability to seed and query the OpenSSL and LibreSSL library's pseudo-random number generators.

Note: On LibreSSL random_egd() is not defined.

📦 EXPORT

None by default.

🔧 Static Methods

• random_bytes (IV num_bytes)
  This function returns a specified number of cryptographically strong pseudo-random bytes from the PRNG. If the PRNG has not been seeded with enough randomness to ensure an unpredictable byte sequence, then a false value is returned.
• random_pseudo_bytes (IV num_bytes)
  This function is similar to random_bytes, but the resulting sequence of bytes are not necessarily unpredictable. They can be used for non-cryptographic purposes and for certain purposes in cryptographic protocols, but usually not for key generation etc.
• random_seed (PV random_bytes_string)
  This function seeds the PRNG with a supplied string of bytes. It returns true if the PRNG has sufficient seeding. Note: calling this function with non-random bytes is of limited value at best!
• random_egd (PV egd_string)
  This function seeds the PRNG with data from the specified entropy gathering daemon. Returns the number of bytes read from the daemon on success, or "-1" if not enough bytes were read, or if the connection to the daemon failed.
  libressl considers this function insecure, so with libressl this function does not exist.
• random_status ()
  This function returns true if the PRNG has sufficient seeding.

🐛 BUGS

Because of the internal workings of OpenSSL's random library, the pseudo-random number generator (PRNG) accessed by Crypt::OpenSSL::Random will be different than the one accessed by any other perl module. Hence, to use a module such as Crypt::OpenSSL::Random, you will need to seed the PRNG used there from one used here. This class is still advantageous, however, as it centralizes other methods, such as random_egd, in one place.

✍️ AUTHOR

Ian Robertson, iroberts@cpan.com

Now maintained by Reini Urban, rurban@cpan.org

📄 LICENSE

This module is available under the same licences as perl, the Artistic license and the GPL.

📚 SEE ALSO

perl(1), rand(3), RAND_add(3), RAND_egd(3), RAND_bytes(3).

perl v5.34.0 2022-02-06 Random(3pm)

📖 NAME 🚀 Quick Reference 📋 SYNOPSIS 🔍 DESCRIPTION 🐛 BUGS ✍️ AUTHOR 📄 LICENSE 📚 SEE ALSO