$password= secret(...);
...
local $password->{stringify_mask}= undef if ref($password) eq 'Crypt::SecretBuffer';
$db= DBI->connect($dsn, $user, $password, \%attr);

##</code><code>##

if ($password isa 'Crypt::SecretBuffer') {
  $db= $password->apply(sub { DBI->connect($dsn, $user, $_[0], \%attr) });
else {
  $db= DBI->connect($dsn, $user, $password, \%attr);
}

##</code><code>##

if (blessed $password && $password->can("unmask_secret_to")) {
  $db= $password->unmask_secret_to(\&DBI::connect, 'DBI', $dsn, $user, $password, \%attr);
} else {
  $db= DBI->connect($dsn, $user, $password, \%attr);
}

##</code><code>##

$db= DBI->connect($dsn, $user, ref $password? $$password : $password, \%attr);