Crypt::Random - Cryptographically Secure, True Random Number Generator.
use Crypt::Random qw( makerandom );
my $r = makerandom ( Size => 512, Strength => 1 );
Crypt::Random is an interface module to the /dev/random device found on most modern Unix systems. The /dev/random driver gathers environmental noise from various non-deterministic sources including, but not limited to, inter-keyboard timings and inter-interrupt timings that occur within the operating system environment. The noise data is sampled and combined with a CRC-like mixing function into a continuously updating ``entropy-pool''. Random bit strings are obtained by taking a
MD5 hash of the contents of this pool. The one-way hash function distills the true random bits from pool data and hides the state of the pool from adversaries.
The /dev/random routine maintains an estimate of true randomness in the
pool and decreases it every time random strings are requested for use. When
the estimate goes down to zero, the routine locks and waits for the
occurrence of non-deterministic events to refresh the pool.
The /dev/random kernel module also provides another interface,
/dev/urandom, that does not wait for the entropy-pool to re-charge and
returns as many bytes as requested. As a result /dev/urandom is
considerably faster at generation compared to /dev/random which is used
only when very high quality randomness is desired.
- makerandom()
-
Generates a random number of requested bitsize in base 10. Following
arguments can be specified.
- Size
-
Bitsize of the random number.
- Strength 0 || 1
-
Value of 1 implies that /dev/random should be used for requesting random
bits while 0 implies /dev/urandom.
- Device
-
Alternate device to request random bits from.
- makerandom_itv()
-
Generates a random number in the specified interval. In addition to the
arguments to makerandom() following attributes can be
specified.
- Lower
-
Inclusive Lower limit.
- Upper
-
Exclusive Upper limit.
- random.c by Theodore Ts'o. Found in drivers/char directory of
the Linux kernel sources.
- Handbook of Applied Cryptography by Menezes, Paul C. van Oorschot
and Scott Vanstone.
- RFC 1321, The MD5 Message Digest Algorithm by Ronald Rivest.
Vipul Ved Prakash, mail@vipul.net
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