I am trying to receive the ASN1 structure of a certificate with Convert::ASN1. I have my certificate in PEM format in a file.

This is what I did:

1. Read the PEM certificate

my $s_filename = 'path/to/file';
my ($dev, $ino, $mode, $nlink, $uid, $gid, $rdev, $size, $atime, $mtim
+e, $ctime, $blksize, $blocks) = stat $s_filename;
open FILE, "<$s_filename" or die "no such file";
binmode FILE;
my $pem_cert;
read FILE, $pem_cert, $size;
close FILE;

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2. Remove 'BEGIN' and 'END'-CERTIFICATE

$pem_cert =~ /-----BEGIN CERTIFICATE-----(?:\r\n?|\n)(.+)(?:\r\n?|\n)-
+----END CERTIFICATE-----/s;
my $s_pem = $1;

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3. Receive the DER format, because Convert::ASN1 works with DER or BER format

my $der   = MIME::Base64::decode($s_pem);

3. Create Convert::ASN1 object

my $asn = Convert::ASN1->new;

4. Configure the encoding of the object – to be DER, because by default Convert::ASN1 works with BER format

$asn->configure(encoding => 'DER');

5. Decode the DER format, which causes the problem

my $out = $asn->decode($der);
if(!defined $out)
{
    die $asn->error();
}
print Dumper($out);

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This is the output:

decode error 0 1918 at /.../Convert/ASN1/_decode.pm line 260.

When I tried to follow the execution using step-by-step debugger, I saw that there is nothing in ASN1's $self->{script}, but I can't understand what that variable stands for.

Can somebody help me?

In reply to Receive certificate ASN1 structure by LoraIlieva

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