How to Save and Share Excel Documents with Multiple Digital Signatures
Question details
The user needs to understand how to successfully share an Excel document containing multiple digital signatures without the signatures becoming invalid on other computers.
- Product
- Microsoft Excel
- Device & OS
- not provided
- Scenario
- Collaborating on a protected workbook that requires official sign-offs from multiple stakeholders across different workstations.
- Observed behavior
- Digital signatures become invalid after saving or are marked as untrusted when the document is opened on a different computer.
Verify that your digital ID or certificate is issued by a recognized Certificate Authority (CA), as self-signed certificates are often not trusted across different computers.
Use a Certificate from a Trusted Provider
To ensure digital signatures remain valid when shared, all signers must use a digital ID from a trusted commercial Certificate Authority.
When a certificate is created locally on one computer (self-signed), it is not automatically trusted by other computers. Sharing an Excel file signed with a local certificate will result in an 'invalid signature' warning for the recipient. For multiple people to sign and validate a document seamlessly, third-party trusted certificates are required.
Acquire a digital certificate from a trusted third-party Certificate Authority (CA) recognized by Microsoft Windows.
Install the digital certificate on your computer by following the specific provider's instructions, ensuring it is added to your personal certificate store.
Open your Excel document, navigate to the 'Insert' tab on the ribbon, and click on 'Signature Line' in the Text group.
Right-click the signature line, select 'Sign', and choose your newly installed trusted digital ID from the list.
Save the document and share it with the next recipient. Subsequent signers should follow the same process using their own trusted IDs.
Manually Trust a Self-Signed Certificate
If you must use a self-signed certificate for internal use, the recipient must manually install and trust the certificate on their machine.
Manage and Protect Spreadsheets Securely in WPS Office
WPS Spreadsheet offers robust document protection features, seamless compatibility with Microsoft Excel files, and an intuitive interface for managing secure documents efficiently.
- 1. Open your file: Launch WPS Office and open your spreadsheet document.
- 2. Access protection tools: Navigate to the 'Review' tab on the top ribbon.
- 3. Apply protection: Click on 'Protect Workbook' or 'Protect Sheet' to secure your sensitive data.
- 4. Set permissions: Set a secure password and specify exactly which editing permissions are allowed for other users.
- 5. Save securely: Save your document. The protection settings will be fully retained even if opened in Microsoft Excel.
Frequently Asked Questions
Why does my Excel digital signature become invalid immediately after saving?
Any modifications made to an Excel document after a digital signature is applied will invalidate the signature. This is a built-in security measure to ensure the document has not been tampered with. Always sign the document only after all edits are finalized.
Can a digital signature prompt for a password when signing an Excel file?
Yes. If your digital certificate was configured with strong private key protection in Windows during installation, the system will prompt you for a password or PIN every time you attempt to apply the signature in Excel.
What is the difference between a self-signed certificate and a trusted CA certificate?
A self-signed certificate is generated on your local machine and is inherently only trusted by your own computer. A CA (Certificate Authority) certificate is issued by a verified third party and is universally trusted across different devices and operating systems, making it necessary for sharing signed documents externally.
