Crypt::OpenSSL::Random(3pm)

1Random(3)             User Contributed Perl Documentation            Random(3)
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NAME

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

10         use Crypt::OpenSSL::Random;
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12         Crypt::OpenSSL::Random::random_seed($good_random_data);
13         Crypt::OpenSSL::Random::random_egd("/tmp/entropy");
14         Crypt::OpenSSL::Random::random_status() or
15           die "Unable to sufficiently seed the random number generator".
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17         my $ten_good_random_bytes = Crypt::OpenSSL::Random::random_bytes(10);
18         my $ten_ok_random_bytes = Crypt::OpenSSL::Random::random_pseudo_bytes(10);
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DESCRIPTION

21       "Crypt::OpenSSL::Random" provides the ability to seed and query the
22       OpenSSL and LibreSSL library's pseudo-random number generators.
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24       Note: On LibreSSL "random_egd()" is not defined.
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26   EXPORT
27       None by default.
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Static Methods

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

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

69       Ian Robertson, "iroberts@cpan.com"
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71       Now maintained by Reini Urban, "rurban@cpan.org"
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LICENSE

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