> **Source:** https://knowledge.leegality.com/document-execution/validate-a-digital-signature > **Site:** Leegality Knowledge Base — https://knowledge.leegality.com > **About:** Leegality is a document execution platform covering eSigning, stamps, NeSL, workflows, and REST API integration. > **Navigation:** Every article on this site has a plain-text version at `.txt` (this format). To get an index of all articles with their `.txt` links, read: https://knowledge.leegality.com/llms.txt > **AI Guide:** For instructions on how to navigate this knowledge base as an AI agent, read: https://knowledge.leegality.com/ai-readable.txt --- # Validate a Digital Signature After a document has been signed, you can validate the digital signature in Adobe Acrobat to confirm that the signature is authentic and the document has not been modified since it was signed. This guide walks you through validating a signature by adding the signer's digital certificate to your list of trusted identities. ## How to Validate a Digital Signature in Adobe Acrobat ### Step 1: Open the Signature Panel First, open the document and access the signature details. 1. In Adobe Acrobat, open the PDF document containing the digital signature. 2. Click the **Signature Panel** button, which is often located in the blue ribbon at the top of the document or as an icon in the right-hand toolbar. > **Info — Check Initial Status** > > This is the step where you will see the initial, unverified status of the signature. It will likely be marked with a yellow warning triangle and the text **"Signature validity is unknown."** This is normal before you complete the validation process. ### Step 2: Begin the Trust Process Now, you will begin the process of telling Adobe to trust the signature. 1. In the Signature Panel on the left, right-click on the signature that has the "validity unknown" status. 2. Select **Show Signature Properties** from the context menu. 3. In the "Signature Properties" window, click the **Show Signer's Certificate** button. ### Step 3: Add to Trusted Certificates This is the most critical step, where you explicitly add the signer's identity to your trusted list. 1. In the "Certificate Viewer" window, navigate to the **Trust** tab. 2. Click the **Add to Trusted Certificates** button. Acknowledge the Adobe Acrobat pop-up by clicking **OK**. > **Info — What and Why: Adding to Trusted Certificates** > > **What it is:** This action takes the signer's digital ID (their certificate) and adds it to a special list within your Adobe software known as "Trusted Identities." > > **Why it's mandatory:** This is a crucial security step. You are manually confirming to the software that you trust the identity of the signer. This prevents Adobe from automatically trusting a potentially fraudulent signature and ensures that only the certificates you have personally vetted are considered valid. ### Step 4: Set Trust Permissions Specify what you want to trust this certificate for. 1. In the "Import Contact Settings" window, check the box next to **Certified documents**. This is the most important option for signature validation. 2. Click **OK** to confirm. 3. Click **OK** again to close the "Certificate Viewer." ### Step 5: Validate the Signature Finally, close the properties window and re-validate the signature. 1. Click **Validate Signature** at the bottom of the "Signature Properties" window. 2. A pop-up will show the validation results. You should now see the green checkmark. 3. Click **Close**. The signature in the document and in the Signature Panel will now display the green checkmark, confirming it is fully validated and trusted. ## Understanding Signature Details After validation, you will see a green checkmark. This is your confirmation. To see the specific digital signature certificate details such as Aadhaar-linked details, click on the now-valid signature. When you click on **Signature Properties** and **Show Signer's Certificate**, you can view an exhaustive list of details that provide comprehensive proof of the signature's authenticity. ### Signature Properties Details This window gives you information about the signature itself and its effect on the document. - **Signed by:** Displays the name of the person who signed the document. - **Signing Time:** Shows the exact date and time the signature was applied, based on the clock of the signer's computer or a trusted time-stamping authority. - **Reason:** The signer can state the purpose of their signature (e.g., "I approve this document," "I am the author of this document"). - **Signature Validity:** A summary that states if the signature is valid. After validation, this will say, "Signature is valid." - **Document Modification:** Confirms that "The document has not been modified since this signature was applied." - **Signer's Identity:** Confirms whether the signer's identity is valid and trusted. - **Certificate Source:** Tells you where the certificate came from (e.g., the Windows Certificate Store, a file). ### Signer's Certificate Details This window provides deep technical details about the digital ID used to create the signature, acting like a digital passport. - **Issued To:** The common name (CN) of the certificate holder (the signer). - **Issued By:** The name of the Certificate Authority (CA) that issued and verified the digital ID (e.g., CDSL, Protean, or Veraysys). - **Validity Period:** The "Valid from" and "to" dates, showing the time frame during which the certificate is considered active and trustworthy. - **Intended purposes:** Lists what the certificate is approved for. - **Serial Number:** A unique number assigned to the certificate by the issuing CA. - **Public Key:** The public portion of the signer's cryptographic key pair.