Digital Signatures
Overview
A digital signature verifies who created or approved a message, file, or transaction — confirming authenticity, integrity, and non-repudiation.
Key concepts
- Authentication, integrity, non-repudiation
- Signing vs. verification
- Sign-with-private-key, verify-with-public-key flow
How it works
A digital signature is a cryptographic method used to verify who created or approved a message, file, or transaction — confirming authenticity, integrity, and non-repudiation.
Core terms
| Term | Meaning |
|---|---|
| Authentication | Confirming the identity of a user, system, or organization. |
| Integrity | Confirming that data has not been altered. |
| Non-repudiation | Proof that a person or organization cannot reasonably deny having performed an action. |
| Signing | Creating a digital signature using a private key. |
| Verification | Checking a digital signature using the related public key. |
| Certificate authority | A trusted organization that issues and validates digital certificates. |
How digital signatures work
- The sender creates a hash of the original data.
- The sender uses their private key to sign that hash.
- The receiver uses the sender's public key to verify the signature.
- A valid signature confirms the data came from the expected sender and wasn't changed.