NAME
MAD::Scrambler - Scramble nibbles of a 32-bit integer
VERSION
version 0.000005
SYNOPSIS
Scrambles a 32-bit integer with a kind of reversible hashing function.
Definitely it is not a cryptographic hash, it is just of reversible
shuffle.
use MAD::Scramble;
my $scrambler = MAD::Scrambler->new(
scrambler => [ 1, 3, 5, 7, 0, 2, 4, 6 ],
bit_mask => 0xFDB97531,
);
my $code = $scrambler->encode( 42 );
## 0xFDB37533
my $number = $scrambler->decode( 0xFDB37533 );
## 42
Very useful for example when you need to expose a reference to a object
into a database in a URL, but you don't want expose the original data.
Note that this is not for solving security problems, sure, since this is
reversible and someone can extract back the original value.
Think in this approach when you want difficult the guess of the value
instead of completely forbid the access to it.
METHODS
new( %args )
Constructor.
%args is a hash which may contains the keys "scrambler" and "bit_mask".
"scrambler" is the order to "shuffle" the nibbles of the number you will
encode. Internally an "unscrambler" is calculated to reverse de process
when you decode a previously encoded number.
"bit_mask" is a 32-bit value to be "XORed" with the new scrambled number
when encoding or decoding.
If any argument is not supplied, it will be randomly generated.
encode( $number )
Scrambles a number into a different one based on the attributes
"scrambler" and "bit_mask".
decode( $code )
Reverses the encoding made by "encode".
nibble_split( $number )
Splits apart the given number in eight nibbles. The least significant
nibbles are put in the lowest indexes.
use MAD::Scrambler qw{ nibble_split };
@nibbles = nibble_split( 0x12345678 );
## ( 8, 7, 6, 5, 4, 3, 2, 1 )
nibble_join( @nibbles )
Joins the nibbles together returning the corresponding integer. The
least significant nibbles are located in the lowest indexes.
use MAD::Scrambler qw{ nibble_join };
my $number = nibble_join( 1, 3, 5, 7, 9, 11, 13, 15 )
## 0xFDB97531
AUTHOR
Blabos de Blebe <
[email protected]>
COPYRIGHT AND LICENSE
This software is copyright (c) 2014 by Blabos de Blebe.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
