NAME¶

Data::Entropy::RawSource::RandomOrg - download entropy from random.org

SYNOPSIS¶

        use Data::Entropy::RawSource::RandomOrg;
        my $rawsrc = Data::Entropy::RawSource::RandomOrg->new;
        $c = $rawsrc->getc;
        # and the rest of the I/O handle interface

DESCRIPTION¶

This class provides an I/O handle connected to a stream of random octets being generated by an electromagnetic noise detector connected to the random.org server. This is a strong source of random bits, but is not suitable for security applications because the bits are passed over the Internet unencrypted. The handle implements a substantial subset of the interface described in IO::Handle.

For use as a general entropy source, it is recommended to wrap an object of this class using "Data::Entropy::Source", which provides methods to extract entropy in more convenient forms than mere octets.

The bits generated at random.org are, theoretically and as far as anyone can tell, totally unbiased and uncorrelated. However, they are sent over the Internet in the clear, and so are subject to interception and alteration by an adversary. This is therefore generally unsuitable for security applications. The capacity of the random bit server is also limited. This class will slow down requests if the server's entropy pool is less than half full, and (as requested by the server operators) pause entirely if the entropy pool is less than 20% full.

Applications requiring secret entropy should generate it locally (see Data::Entropy::RawSource::Local). Applications requiring a large amount of entropy should generate it locally or download it from randomnumbers.info (see Data::Entropy::RawSource::RandomnumbersInfo). Applications requiring a large amount of apparently-random data, but not true entropy, might prefer to fake it cryptographically (see Data::Entropy::RawSource::CryptCounter).

CONSTRUCTOR¶

Data::Entropy::RawSource::RandomOrg->new

Creates and returns a handle object referring to a stream of random octets generated by random.org.

METHODS¶

A subset of the interfaces described in IO::Handle and IO::Seekable are provided:

$rawsrc->read(BUFFER, LENGTH[, OFFSET])

$rawsrc->getc

$rawsrc->ungetc(ORD)

$rawsrc->eof

Buffered reading from the source, as in IO::Handle.

$rawsrc->sysread(BUFFER, LENGTH[, OFFSET])

Unbuffered reading from the source, as in IO::Handle.

$rawsrc->close

Does nothing.

$rawsrc->opened

Retruns true to indicate that the source is available for I/O.

$rawsrc->clearerr

$rawsrc->error

Error handling, as in IO::Handle.

The buffered ("read" et al) and unbuffered ("sysread" et al) sets of methods are interchangeable, because no such distinction is made by this class.

Methods to write to the file are unimplemented because the stream is fundamentally read-only. Methods to seek are unimplemented because the stream is non-rewindable; "ungetc" works, however.

SEE ALSO¶

Data::Entropy::RawSource::CryptCounter, Data::Entropy::RawSource::Local, Data::Entropy::RawSource::RandomnumbersInfo, Data::Entropy::Source, <http://www.random.org>

AUTHOR¶

Andrew Main (Zefram) <zefram@fysh.org>

COPYRIGHT¶

Copyright (C) 2006, 2007, 2009, 2011 Andrew Main (Zefram) <zefram@fysh.org>

LICENSE¶

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.