sub decrypt { 
    my ($self, %params) = @_;
    my $key = $params{Key}; 
    my $cyphertext = $params{Cyphertext};
    $cyphertext = unpack "u*", $cyphertext if $params{Armour};
    my $plaintext;
    my $blocksize = ((bitsize ($key->n)) / 8); 
    my @segments = steak ($cyphertext, $blocksize);
    for (@segments) {
        $plaintext .= $self->{eme}->decrypt (Cyphertext=> $_, Key => $key)
            || return $self->error ($self->{eme}->errstr, \$key, \%params);
    }
    return $plaintext;
}