A tamper-proof document in Zoho Sign is one where any modification made to the PDF after signing is cryptographically detectable. Zoho Sign embeds a digital seal in completed documents that fails validation if the document content is altered in any way, providing evidence that the document in its current form is exactly what the signatories signed.
When a Zoho Sign document is completed, a cryptographic hash of the full document content is generated and embedded as part of the digital seal. Any subsequent change to the document — even adding a period or changing a number — produces a different hash that does not match the embedded value, revealing the tampering.
Tamper-evident sealing is a key requirement for electronically signed documents to be accepted as legal evidence. Without it, a party could theoretically alter the document after signing and claim the altered version is the original. Zoho Sign’s seal makes such alterations immediately detectable.
Once all signatures are collected, Zoho Sign applies a cryptographic seal to the final PDF. The seal generates a unique hash of the document’s contents and embeds it digitally. If any character, pixel, or metadata in the document is modified after sealing, the hash will not match when verified, indicating tampering. PDF readers that validate digital signatures display a warning when a sealed document has been altered.
Open the signed PDF in Adobe Acrobat Reader and check the Signatures panel. Acrobat validates the embedded digital certificate and displays whether the document is certified and whether any modifications have been made since signing. A green checkmark indicates the document is unmodified. Zoho Sign also provides an online document verification tool where you can upload a completed document to confirm its authenticity.
Once all signatures are collected, Zoho Sign applies a cryptographic seal to the final PDF. The seal generates a unique hash of the document’s contents and embeds it digitally. If any character, pixel, or metadata in the document is modified after sealing, the hash will not match when verified, indicating tampering. PDF readers that validate digital signatures display a warning when a sealed document has been altered.
Open the signed PDF in Adobe Acrobat Reader and check the Signatures panel. Acrobat validates the embedded digital certificate and displays whether the document is certified and whether any modifications have been made since signing. A green checkmark indicates the document is unmodified. Zoho Sign also provides an online document verification tool where you can upload a completed document to confirm its authenticity.
Aaxonix is a certified Zoho implementation partner based in Pune. Architecture-first, no surprises.