Digital signatures
A digital signature is an electronic signature that can be used for these purposes:
- To authenticate the identity of the sender of a message or the signer of a document.
- To ensure that the original content of the message or document that has been sent is unchanged.
Digital signatures are easily transportable, cannot be imitated by someone else, and can be automatically time-stamped. A digital signature can be used with any kind of message, whether it is encrypted or plain text.
Digital signatures provide these features:
- Authentication
Digital signatures are used to authenticate the source of messages. The ownership of a digital signature key is bound to a specific user. Therefore, a valid signature shows that the message was sent by that user.
- Integrity
In many scenarios, the sender and receiver of a message require assurance that the message has not been changed during transmission. To provide this feature, digital signatures use cryptographic message digest functions.
- Non-repudiation
Digital signatures ensure that senders who have signed the information cannot, at a later stage, deny they have signed it.