Andrew Main (Zefram) > Data-Entropy-0.007 > Data::Entropy::RawSource::RandomnumbersInfo



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Data::Entropy::RawSource::RandomnumbersInfo - download entropy from


        use Data::Entropy::RawSource::RandomnumbersInfo;

        my $rawsrc = Data::Entropy::RawSource::RandomnumbersInfo->new;

        $c = $rawsrc->getc;
        # and the rest of the I/O handle interface


This class provides an I/O handle connected to a stream of random octets being generated by a quantum random number generator (from the company id Quantique) connected to the server at the University of Geneva. 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 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. Applications requiring secret entropy should generate it locally (see Data::Entropy::RawSource::Local). Applications requiring a large amount of apparently-random data, but not true entropy, might prefer to fake it cryptographically (see Data::Entropy::RawSource::CryptCounter).



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


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

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

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

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

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


Does nothing.


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


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.


Data::Entropy::RawSource::CryptCounter, Data::Entropy::RawSource::Local, Data::Entropy::RawSource::RandomOrg, Data::Entropy::Source,


Andrew Main (Zefram) <>


Copyright (C) 2006, 2007, 2009, 2011 Andrew Main (Zefram) <>


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

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