A digital signature is a mathematical algorithm that validates the authenticity and integrity of a message or document by generating a unique hash of the message or document and encrypting it using the sender's private key1. The primary reason for using a digital signature is to authenticate the sender of a message, as only the sender has access to their private key and can produce a valid signature2. A digital signature also verifies the integrity of the data, as any modification to the message or document will result in a different hash value and invalidate the signature1. However, a digital signature does not provide availability or confidentiality to the transmission, as it does not prevent denial-of-service attacks or encrypt the entire message or document3.
References
1: Understanding Digital Signatures | CISA
2: Signature Verification | CISA
3: SECFND: Digital Signatures from Skillsoft | NICCS