SecureBlackbox Knowledge Base

Recent PDF Articles


Signature background image is not printed or corrupted. How to fix it?

Depending on the image format, if the incorrect image dimension ( TElPDFImage. Width and Height properties) is specified, Adobe software will display a corrupted…

When I try to sign the data using the certificate, contained in Windows (with non-exportable private key), only MD5 hash algorithm works, even if I manually specify SHA* algorithm. Why so?

Windows CryptoAPI doesn't support SHA algorithms for signing by default, so SecureBlackbox reverts to MD5 if CryptoAPI must be used for signing (as it happens in…

When I use Acrobat 6.0, click the signature and hit "e;Signature Properties"e;, I get an "e;Acrobat error. Bad parameter."e; Why?

Try to assign the non-empty value to the ElPDFSignature.AuthorName property. Though this property is marked as optional in PDF specification, Adobe Reader 6 fail…

When I specify Windows (or PKCS#11) certificate storage for signing, I get "e;No signing certificate found"e; error. Why?

Please check that the storage is not empty, i.e. it contains at least one certificate with a private key. You need a certificate with a private key to sign the d…

When I open the signed document with Acrobat, it says that 'EldoS.SecureBlackbox' handler, used to create the signature, could not be found. What should I do?

Adobe Acrobat identifies the security handler that created the signature by its name. By default, SecureBlackbox creates signatures with name. However, you can s…

When loading large PDF document, OutOfMemory error happens. How do I deal with it?

In this case you should handle TElPDFDocument.OnCreateTemporaryStream and/or TElPDFDocument.PDFFile.OnCreateTemporaryStream events, create a temporary file on th…

What does "EElPDFDocumentError: Internal error ElPDFDocument.InsertActualSignatureInformation.2" mean?

What does "EElPDFDocumentError: Internal error ElPDFDocument.InsertActualSignatureInformation.2" mean:

I have a license for PDFBlackbox, XMLBlackbox or PKIBlackbox. How do I use timestamping?

How to use timestamping when possesing a license for PDFBlackbox, XMLBlackbox or PKIBlackbox.

What is CDS signature? Does SecureBlackbox support it?

CDS signature is a signature with a certificate chain which ends up with a root certificate issued by Adobe. The idea is that since Adobe software knows the root…

How do I specify position of the visible signature?

To fix the position of the signature widget, you can take one of the following approaches: Use properties of ElPDFSignatureWidgetProps class. The instance of thi…

I have timestamped the document, but Acrobat doesn't show it. Why?

Acrobat is very sensitive to the TSP reply, which is given by the TSP server. For example, the certificate chain must be completely validated by Acrobat in order…

Why is memory consumption much larger, than the size of the PDF file?

When the PDF file is loaded, there's a tree of objects built in memory. When the PDF has many small objects, memory consumption grows significantly and can be ma…

Implementing PAdES signing of PDF documents using SecureBlackbox

The article describes how to perform advanced signing of PDF documents according to PAdES specification using SecureBlackbox.

(VCL) I have a license for PDFBlackbox. When I open PDFSigner sample in IDE, I get an error saying that TElHTTPSClient component is not installed. Where is the component?

PDFSigner sample application uses TElHTTPSClient component, which is not covered by your PDFBlackbox license. For information about timestamping in your case ple…

I have a license for PDFBlackbox. When I run PDFSigner sample, I get an error "The license key doesn't enable requested functionality". Why is that?

This error is shown when you attempt to use timestamping, because PDFSigner sample application uses TElHTTPSClient component, which is not covered by your PDFBla…

Signing documents according to Spanish Factura format (government invoices)

Here you will find the sample code, which signs "factura" electronic XML documents (Spanish government's invoices), as described in this document. The resulting …