I use the following

sub encode {
    $_ = join '', @_;
    s/(\W)/'%'.sprintf("%02lx",ord($1))/ge;
    return $_;
}

sub decode {
    $_ = join '', @_;
    s/%([a-fA-F\d][a-fA-F\d])/chr(hex($1))/ge;
    return $_;
}
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Works for me
                - Ant