my $s_pdf_file_to_sign = 'pdf_file_to_sign';
my $s_private_key_file = 'private_key_file';
my $s_cert_file = 'certificate_file';

##</code><code>##

my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
		$atime,$mtime,$ctime,$blksize,$blocks) = stat $s_pdf_to_sign;
open FILE, "<$s_pdf_to_sign" or die "no such file";
binmode FILE;
my $s_pdf_to_sign_string;
read FILE, $s_pdf_to_sign_string, $size;
close FILE;


##</code><code>##

($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
		$atime,$mtime,$ctime,$blksize,$blocks) = stat $s_private_key;
open FILE, "<$s_private_key" or die "no such file";
binmode FILE;
my $s_private_key_content;
read FILE, $s_private_key_content, $size;
close FILE;

##</code><code>##

my $s_private_key_string = $s_private_key_content;
my $oref_rsa_priv = Crypt::OpenSSL::RSA->new_private_key($s_private_key_content) or die "new_private_key error";