When you reach out to a software company’s support service, you want assurance that the person handling your case is not just knowledgeable but an expert in resolving your specific issue. At PDFKit, our support team consists of engineers who not only understand our products inside out but also possess extensive expertise in the intricate workings of the PDF format. This unique blend enables us to tackle even the most challenging PDF-related problems with precision and efficiency.
Consider a recent scenario encountered by one of our clients: they encountered difficulty with a PDF document that had been digitally signed multiple times. Initially, everything seemed to function smoothly after the first signature, but subsequent signatures rendered the initial one invalid.
To delve deeper into understanding digital signatures and how they operate, it’s helpful to explore our blog articles dedicated to this topic. Digital signatures in PDFs serve as cryptographic features, validating the authenticity of the file and detecting any alterations made to it.
Identifying the Issue:
Understanding how digital signatures operate is crucial to troubleshooting. Each time a PDF is signed, information about the signature is added incrementally to the document, without overwriting existing data. When faced with an issue related to a PDF signature, it’s essential to focus on these incremental additions.
In our investigation, we began by examining the document in a text editor, searching for incremental portions marked by the “%%EOF” string. These sections contain new cross-reference tables and definitions of updated PDF objects. We isolated these incremental sections, preserving the initial digital signature while removing subsequent additions.
Resolving the Problem:
Two common ways digital signatures can become invalid are alterations to the protected text or unauthorized changes to the PDF between signatures. By systematically removing incremental parts, we ensured that the protected content remained unaltered, narrowing down the issue to the material added between the first and second signatures.
To correct the erroneous incremental section, we made adjustments using a text editor while updating the cross-reference table offset. By carefully manipulating the document and replacing byte offsets, we restored the validity of the first digital signature, allowing for subsequent signatures without invalidation.
Conclusion:
At PDFKit, our support approach entails meticulous root-cause analysis to provide tailored solutions to our customers’ PDF-related challenges. You can rely on our expertise to navigate the complexities of PDF troubleshooting while you focus on the unique aspects of your software. Contact PDFKit’s support channels for comprehensive assistance with all your PDF needs.