Feature Request: Add ceritificate page at the end of file

[ViniciusgCaetano]

Feature Title

Add ceritificate page at the end of file

Feature Description

As I tested, there's only to download the signed pdf or the certificate in separeted files. there is a way to merge these two as the file becomes first and the completion certificates becomes in the end of the file?

What type of feature are you requesting?

UI/UX Improvement

Importance

Medium

Additional Context

No response

Code of Conduct

• I agree to follow this project's Code of Conduct
• I have searched the existing issues & discussions to make sure that this is not a duplicate.

[sophymarine]

That behaviour (“download the signed PDF or the certificate as separate files”) usually traces back to when the signature gets applied. If the PDF is already cryptographically signed, adding another page afterwards breaks the signature unless the document was certified for incremental updates.

Common approach: build the full document first. Original file, then the rendered audit or certificate page. After that, sign the combined PDF. Libraries like PDFBox or iText handle the page merge step before signing without much trouble.

If OpenSign signs the base document and only produces the certificate later, that ordering is likely the problem. Moving certificate generation earlier in the pipeline and signing the merged file tends to avoid the signature invalidation.