The result of this hash function is always identical provided that the block of data has not been modified. A hash is a mathematical function that converts an arbitrary block of data into a fixed-size string. Digital signatures in PDF documents use the concept of hashing to prevent such a scenario.

Imagine that somebody intercepts a PDF document with some important contractual agreement and tries to modify it to show different terms. How the Integrity of a PDF Document Is Checked That the person who claims to have authored the document is really the person who created it. That the document has not been modified by an unknown person. This piece of information is placed inside a document, and it lets PSPDFKit and other PDF readers check two important things:

OverviewĪ digital signature in a PDF is the equivalent of an ink signature on a paper document, but it’s much more secure. In order to ensure that a document has not been modified by someone other than its author, and to verify that the author is who we expect and not somebody else, digital signatures are necessary. PDF documents are used to share all kinds of information, including that of a confidential nature or with a legal value, like a contract.

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