The Digital Signature Standard (DSS), specified in FIPS 186-4, defines algorithms for generating and verifying digital signatures. The primary security services provided by a digital signature are authentication (verifying the sender's identity), data integrity (ensuring the message has not been altered), and non-repudiation (preventing the sender from denying the message). DSS is not designed to provide confidentiality. While the underlying algorithms like RSA can be used for encryption, the standard itself is exclusively for creating signatures, not for encrypting data to keep it secret.

B. Integrity: DSS provides integrity by using a secure hash function on the message before signing. Any change to the message results in a different hash, causing signature verification to fail.

C. Digital signature: This is the core function of the standard. DSS explicitly defines the methods and algorithms (DSA, RSA, ECDSA) for creating and verifying digital signatures.

D. Authentication: DSS authenticates the origin of a message. Since the signature is created with the signer's private key, successful verification with the public key proves the message came from the claimed sender.

1. National Institute of Standards and Technology (NIST). (2013

July). FIPS PUB 186-4: Digital Signature Standard (DSS). U.S. Department of Commerce. In Section 1

"Specification

" the document states its purpose is for applications requiring a digital signature to "detect unauthorized modifications to data and to authenticate the identity of the signatory." It makes no mention of providing encryption or confidentiality. (Page 1

Section 1).

2. Purdue University. (n.d.). CS 555: Introduction to Cryptography - Lecture 20: Digital Signatures. "The main goal of digital signatures is to provide authenticity

including data integrity and origin authentication. It also provides non-repudiation... Digital signatures do not provide confidentiality." (Slide 3).

3. Katz

J.

& Lindell

Y. (2014). Introduction to Modern Cryptography (2nd ed.). CRC Press. In Chapter 12

the text clearly distinguishes the security goals of digital signatures (integrity and authentication) from those of encryption schemes (confidentiality). DSS is presented as a standard for the former. (Chapter 12

Section 12.1

"Definition of Secure Signatures").