When you seal a PDF document through Signicat, you apply a cryptographic signature on the document, making it impossible to change without breaking the seal.
In an electronic signing process, you need to be sure of the integrity of the signed document to ensure that it has not been changed or tampered with in any way. Through Signicat's regular electronic signing process, the documents are protected and sealed when the document is packaged.
If you have documents (PDFs) that are not electronically signed through Signicat, but where the integrity of the document and non-repudiation is still important – Sealing is appropriate. The default result format of the sealed document is an electronically signed PDF, called PAdES (PDF Advanced Electronic Signatures). The sealed document can be viewed using any PDF reader. In some readers such as Adobe Reader, the reader will verify that the seal is valid and give warnings if the seal is broken.
# How to apply an electronic seal
Electronic seals is typically added by an organisation who want to ensure the integrity of their documents. The sealing of documents is can be automated and applied to your documents through our SealingService API. Bulk sealing of documents is easy to do through the API and can be used to seal large quantities of documents.