What are the approved digital signature standards?

• A. DSA, RSA, and ECDSA
• B. DSA
• C. RSA
• D. ECDSA

Answer: (A)

Approved digital signature standards are the algorithms the federal framework recognizes for creating and validating signatures. In U.S. federal guidelines, the Digital Signature Standard identifies multiple algorithms as approved options, not just one. DSA, RSA, and ECDSA are all recognized as acceptable for digital signatures, each with its own security and key-size characteristics. DSA relies on discrete logarithms, RSA uses large modular exponentiations with widely deployed key sizes, and ECDSA uses elliptic curves to achieve comparable security with smaller keys. Because the standards embrace this trio, the best answer is the one that lists all three. Choosing only one of the algorithms misses part of what the federal standards approve.