In today’s digital world, many documents are shared online. Whether it is a business agreement, government form, or personal file, it is important to make sure that the document is genuine and has not been changed. This is where digital signatures play a major role.
A digital signature is like a seal that proves the identity of the sender and confirms that the document is original. But how do you know if the digital signature on a document is valid? This article will help you understand how to verify a digital signature in simple and clear words.
What is a Digital Signature?
A digital signature is a secure electronic form of a signature. It is used to sign electronic documents in a way that is legal, secure, and verifiable. It works using a technology called public key infrastructure (PKI).
Digital signatures:
- Prove that the document is signed by the right person
- Show if the document was changed after signing
- Are used in PDFs, Word files, emails, and more
Why Verifying a Digital Signature is Important
Before accepting a signed digital document, you must verify the digital signature. This helps to:
- Check the identity of the sender
You want to make sure that the person or organization who sent the document is real. - Confirm that the document has not changed
If the document was edited after it was signed, the signature becomes invalid. - Avoid fraud or misuse
Verifying a signature protects you from fake documents.
Basic Terms to Know
Before we learn how to verify a digital signature, let’s understand a few basic terms:
- Certificate Authority (CA): A trusted company that issues digital signatures.
- Digital Certificate: A file that proves the identity of the signer.
- Public Key: Used by the receiver to check the signature.
- Private Key: Used by the sender to create the signature.
Common File Types with Digital Signatures
You can find digital signatures in many document types like:
- PDF files
- Microsoft Word files
- Emails (especially official ones)
- Zip or software files
Each type may have its way of verifying the signature.
How to Verify a Digital Signature on a PDF Document
Most PDFs are signed using Adobe Acrobat Reader or similar PDF tools. Here’s how you can check the digital signature on a PDF:
1: Visit Our Website
- Go to our website to start the process.
2: Fill in Your Details
- User Type: Choose if you are an individual or an organization.
- Certificate Type: Pick if you need it just for signing documents or for both signing and encryption.
- Validity: Choose how long you want the certificate to last.
- Personal Info: Enter your name, phone number, email, and address.
- Agree to Terms: Check the box to agree to the terms.
- Submit: Click the submit button.
3: Choose Token Option
- Already Have a Token?: If you have a USB token, choose “No.” If you need a new one, choose “Yes.”
4: Make Payment
- Payment: Enter your payment details and choose how you want to pay (net banking, credit card, debit card, or UPI).
5: Complete the Process
- Review: Make sure all your information is correct.
- Submit: Click submit and wait for a confirmation email.
6: Get Your Digital Signature
- You’ll receive your digital signature on a USB token drive after processing.
What If a Signature Is Invalid or Unknown?
Sometimes, you may see that a signature is:
- Invalid: This could be because the document was changed after signing.
- Unknown: Your system or software may not recognize the certificate authority.
In this case:
- Try updating your software
- Check the certificate manually
- Contact the signer to confirm
Online Tools to Verify Digital Signatures
There are also websites and tools that help you check digital signatures:
- DGFT website (for Indian government documents)
- eMudhra or Sify for DSC checks
- PDF signature checker tools online
Use these tools with caution and always prefer verifying through trusted software.
Tips for Safe Digital Signature Verification
- Use Official Software Always use Adobe Reader, MS Word, or Outlook for checking.
- Keep Your Software Updated Outdated software may not recognize valid signatures.
- Be Careful with Unknown Signers Do not trust signatures from unknown or suspicious sources.
- Cross-check with the Sender If you are unsure, ask the person who sent the document.
- Check Certificate Expiry Make sure the certificate is still valid and has not been revoked.
Legal Importance of Verifying Digital Signatures
In many countries, digital signatures are legally accepted. But for them to be valid in court or business:
- They must be verified correctly
- They must be issued by a licensed Certificate Authority
- The document must not be changed after signing
Understanding Digital Signatures in Detail
A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. It works on public-key infrastructure (PKI), where each signer has a private key (used to sign) and a public key (used to verify).
- Private Key – Kept secret by the signer, used to create the signature.
- Public Key – Shared openly, used by recipients to verify the signature.
- Hash Function – Ensures that even the smallest change in the document will invalidate the signature.
For example:
- If you sign a PDF contract digitally, the system generates a unique fingerprint of the document and encrypts it with your private key.
- When someone opens the document, their software uses your public key to decrypt the signature. If the decrypted fingerprint matches the document’s current fingerprint, the signature is valid.
Suggested read- What is E-Mudra
Conclusion
Digital signatures are a powerful way to protect documents and confirm the sender’s identity. But the real value comes when you can verify that the signature is valid. Whether it’s a PDF, Word file, or email, learning how to verify digital signatures helps you stay safe, avoid fraud, and trust what you receive.
Using simple steps and trusted software, you can check any digital signature on your own. It is a skill that is becoming more important every day in both business and personal life.
If you deal with digital documents often, always take a moment to verify the signature before you accept or act on the file. It only takes a minute, but it protects you from big risks.