Chapter 7iii: RSA, DH and Beyond

Question 1

RSA, DH and Beyond| Public Key Cryptography

Answer 1

Quantum computers (QCs) use qubits, enabling faster problem-solving than classical computers. Grover’s and Shor’s algorithms threaten cryptographic security, compromising RSA and key exchanges. While QCs exist, qubit capacity is limited, but experts predict a major breakthrough by the mid-2030s.

Question 2

Post-Quantum Cryptography (PQC) vs. Quantum Cryptography

Sum up the main differences.

Answer 2

Question 3

Why Does PQC Matter Now?

Why should we care about a problem that may become relevant in the more (or less) distant future? Let us assume the so-called “quantum leap” has ocurred and we are not prepared.
What effects would it have?

Answer 3

1. long term data security
2. Public Key Infrastructures and similar structures
3. competition

Question 4

Challenges in Transitioning to PQC

Explain them.

Answer 4

Question 5

What is being shown in this slide?

Answer 5

NIST defined five security levels for cryptographic algorithms based on the hardness to break various AES and SHA variants. For each of the security levels, NIST also recommends a certain (public) key size for asymmetric algorithms to achieve similar strength.

NIST Security Levels vs. Key Sizes of “Classic” Asymmetric Algorithms

Question 6

What is being shown in this slide?

Answer 6

NIST Security Levels vs. Key Sizes of PQC Algorithms
The novel and standardized PQC schemes can be parameterized with different key sizes to achieve security according to the five NIST security levels.