>>426 Perl 5.30

# -*- coding: utf-8 -*-
no warnings 'experimental::signatures';
use feature qw(say signatures); # lexical_subs);
sub ReversibleHash_Encode($S, $C) {
　@a = unpack 'C*', $S;
　$l = @c = split '', $C;
　my $o; ++$o while $l**$o < 256; #my $o = 1 + log(256)/log $l;
　use integer;
　my sub _enc($i) { join '', reverse map{($i, $m) = ($i/$l, $i%$l); $c[$m]} 1..$o }
　%e = map{$_ => '%'._enc $_} 0..255;
　join '', map{$e{$_}} @a;
}
sub ReversibleHash_Decode($S, $C) {
　@s = $S =~ /(%\w+)/g;
　%d = map{$e{$_} => $_ } keys %e;
　pack 'C*', map{$d{$_}} @s;
}
say $t = ReversibleHash_Encode 'ウィキペディア', '0123456789';
say $s = ReversibleHash_Decode $t, '0123456789';
$Ch = "abcdefghijklnmopqrstuvwxyz0123456789";
say $t = ReversibleHash_Encode $s, $Ch;
say $s = ReversibleHash_Decode $t, $Ch;


実行結果
~ $ perl 15_426.pl
%227%130%166%227%130%163%227%130%173%227%131%154%227%131%135%227%130%163%227%130%162
ウィキペディア
%gl%dw%ew%gl%dw%et%gl%dw%e3%gl%dx%ek%gl%dx%d1%gl%dw%et%gl%dw%es
ウィキペディア