my %mapping =
(
A => [ '@', '|\\', '4', '^', '/-\\', ],
B => [ '|3', ']3', '8', 'ß', ],
C => [ '(', '©', ],
D => [ '|)', '])', 'Ð', ],
E => [ '3', '£', ],
F => [ '#', '|=', ],
G => [ '9' ],
H => [ '|-|' ],
I => [ '1', '!', '][', '¡', ],
J => [ '_|' ],
K => [ '|<', '|{', ],
L => [ '|_', '|', '1', ],
M => [ '|\\/|', '/\\/\\', '^^', ],
N => [ '|\\|', '/\\/', ],
O => [ '()', '0', '°' ],
P => [ '|D', 'þ', 'Þ', ],
Q => [ '&', '¶', ],
R => [ '|2', '®', ],
S => [ '$', '5', '§', ],
T => [ '+', '7', ],
U => [ '|_|' ],
V => [ '\\/' ],
W => [ '|/\\|', '\\/\\/', '|/\\/', '\\/\\|', ],
X => [ '><', '×', '}{', ],
Y => [ '¥', 'ý', ],
Z => [ '2' ],
);

while (<>) {
    foreach my $letter (keys %mapping) {
        $_ =~ s/$letter/$mapping{$letter}[rand(@{$mapping{$letter}})]/gi;
    }
    print;
}