Digital signatures allow a message sender to be authenticated to a third party. The sender uses their private key to sign a message, and anyone can use the sender's public key to verify the signature and confirm it was signed by the sender. However, digital signatures are vulnerable to attacks where the private key is stolen or compromised, or where an attacker manipulates public keys. Proper key management and protocols are important for secure digital signatures.

1. Bishop: Chapter 10 Key Management: Digital Signature