use Business::CreditCard::Obscure qw(obscure); print obscure('4444333322221111'); # 4444********1111 use Business::CreditCard::Obscure obscure => { head => 4, tail => -4, replacement => '!' }; print obscure('4444333322221111'); # 4444!!!!!!!!1111 use Business::CreditCard::Obscure obscure => { head => 4, -as => 'obscurevisa' }, obscure => { head => 3, tail => -3, -as => 'obscurediner' }; print obscurevisa('4444333322221111'); # 4444********1111 print obscurediner('444333222111'); # 444******111 #### package Business::CreditCard::Obscure; use strict; use warnings; use Sub::Exporter -setup => { exports => [ obscure => \&build_obscure ] }; sub build_obscure { my ( $class, $name, $arg ) = @_; $arg->{head} ||= 0; $arg->{tail} ||= -4; $arg->{replacement} ||= '*'; return sub { my $data = shift; substr( $data, $arg->{head}, $arg->{tail} ) =~ s/./$arg->{replacement}/g; return $data; } } 1;