crypt-dict.pl

#!perl

# Dictionary encrypted so the keys aren't enumerable, but where possession of
# a key allows you to decrypt the value.
#
# eg: a translations file where you don't want people to be able to know all
#     the translated strings, but you do want someone with a string to be able
#     to translate it

use strict;
use warnings;
use Crypt::CBC;

use Data::Printer;

my $enc = encrypt({ foo => 'bar', bar => 2 });
p $enc;

my $dec = { map { $_ => decrypt( $enc, $_ ) } qw/foo bar/ };
p $dec;

sub encrypt {
    my $hash = shift;
    my $new_hash = {};

    for my $old_key ( keys %$hash ) {
        # Replace with sensible hashing system
        my $new_key = crypt( $old_key, 'na' );
        # Replace with a more sensibly-derived key
        my $cipher = Crypt::CBC->new( -key => $old_key, -cipher => 'Cipher::AES' );
        $new_hash->{ $new_key } = $cipher->encrypt( $hash->{ $old_key } );
    }

    return $new_hash;
}

sub decrypt {
    my ( $hash, $key ) = @_;
    my $hashed_key = crypt( $key, 'na' );
    my $encrypted_value = $hash->{ $hashed_key } || return;

    my $cipher = Crypt::CBC->new( -key => $key, -cipher => 'Cipher::AES' );
    return $cipher->decrypt( $encrypted_value );
}