Technology
How does a digital signature work?
A digital signature proves a message or document is genuine and unaltered. The sender signs it using a private key, and anyone can verify it with the matching public key. If the content changes even slightly, the signature no longer checks out.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how a digital signature works.
Step by step
- 1The sender signs data with a secret private key.
- 2Anyone can verify it with the public key.
- 3It proves who sent it and that it's unchanged.
- 4Altering the content invalidates the signature.
Frequently asked questions
- How does a digital signature work?
- The sender signs with a private key; others verify with the public key, confirming authenticity and integrity.
- What does a digital signature prove?
- That a message genuinely came from the signer and hasn't been altered since signing.
- Where are digital signatures used?
- Secure email, software updates, legal e-signatures, and blockchain transactions.