Digital Signatures
A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very high confidence that the message was created by a known sender (authenticity), and that the message was not altered in transit (integrity).
A digital signature is a unique cryptographic code that’s affixed to documents, email, software and digital certificates. It can be used to prove ownership of the certificate and the accompanying key pair.
Digital signatures employ asymmetric cryptography (PKI). In many instances, they provide a layer of validation and security to messages sent through a non-secure channel: Properly implemented, a digital signature gives the receiver reason to believe the message was sent by the claimed sender.
Digital Certificates
A digital certificate, such as an SSL certificate, is a cryptographic file that binds a key pair to a validated entity. It both facilitates signatures and is facilitated by signatures.
When a digital certificate is issued, it’s signed by the certificate authority (CA) that’s issuing it. When a client receives that certificate, it performs the aforementioned function to ensure that the certificate was signed by a trusted entity. So, assuming the certificate is signed by a trusted CA, it can be trusted.
What’s the Difference Between a Digital Signature and Digital Certificate?
A digital signature is a cryptographic code that gets affixed to other files to assert identity and authenticity. A digital certificate is a cryptographic file that contains a digital signature. The certificate is what binds the signing key to the entity. And the digital signature is what lets clients know that entity is trusted, and that what’s signed is authentic.
Digital signature is used to verify authenticity and integrity to ensure that the message is sent by the known user and not modified in transit, while digital certificate is used to verify the identity of the user (sender or receiver).