1. Is this relevant to me?

This article is relevant to all users who receive or manage sealed PAdES PDFs through our platform. It is especially important for compliance officers, legal teams, or any recipient who needs to independently prove that a document has not been altered since its original creation.

2. What is it?

Every document processed by our platform is assigned a SHA-512 hash (as seen in your Document Summary and Attachments list).

Think of this hash as a digital fingerprint. It is a unique string of characters generated from the original file content before any digital seals or visual watermarks are added. If even a single comma is changed in the PDF, the resulting "fingerprint" will be completely different. By providing this key, we allow you to verify the absolute integrity of your files.

• Main Document: Found under the "SHA-512" section of your "Document Summary".

• Attachments: Each attachment has its own unique SHA-512 hash listed in the Attachments table.

3. How does it work?

To verify your document, you can "re-calculate" its hash on your own computer and compare it to the one provided in our summary. If they match, the document is 100% authentic.

3.1 Official Verification Tools (No download required)

3.1.1 For Windows Users:

1. Open the Start Menu, type cmd, and press Enter.

2. Type the following command (but don't press Enter yet): certutil -hashfile

3. Drag and drop your PDF file directly into the window. This will automatically add the file path.

4. Type SHA512 at the end and press Enter.

   • Example: certutil -hashfile C:\Downloads\Sample_PDF.pdf SHA512

5. Compare the resulting long string of letters and numbers with the one in your Document Summary.

3.1.2 For Mac Users:

1. Open Terminal (found in Applications > Utilities).

2. Type the following command (include the space at the end): shasum -a 512

3. Drag and drop your PDF file into the Terminal window.

4. Press Enter.

5. The system will display the SHA-512 hash for you to compare.