CMM7XX
Asymmetric Cryptography
Session 4: RSA and Key Management
Learning Objectives
- Deconstruct the Key Distribution Problem and the Diffie-Hellman solution.
- Master the mathematical foundation of RSA (Euler's Totient function).
- Analyze the mathematical advantages of Elliptic Curve Cryptography (ECC) over RSA.
- Evaluate the architecture of Public Key Infrastructure (PKI) and X.509 standards.
- Understand the threats posed by quantum computing (Shor's Algorithm).
Part 1: Key Exchange & RSA Mathematics
Duration: 1.5 Hours
15 Minute Break
Please return promptly for Part 2.
Part 2: ECC & Public Key Infrastructure
Duration: 1.5 Hours
Introduction to Task 2
Understanding PKI requires inspecting the actual cryptographic structures used in TLS handshakes.
We will use OpenSSL to deconstruct a live X.509 certificate chain from a major website.
Task 2: PKI Certificate Analysis
Timing: 50 minutes
Open your terminal and run: openssl s_client -connect google.com:443 -showcerts
- Extract the primary server certificate block and save it to
cert.pem.
- Run
openssl x509 -in cert.pem -text -noout to decode it.
- Identify the Signature Algorithm used (e.g., sha256WithRSAEncryption).
- Locate the Subject Alternative Names (SANs). Why are these used instead of just the Common Name (CN)?
- Identify the CRL/OCSP URIs. Discuss how browsers use these endpoints to handle certificate revocation.
Summary & Next Steps
- Asymmetric cryptography solves the key distribution problem but is computationally heavy; it is used to exchange symmetric keys (Hybrid Cryptography).
- PKI is the backbone of trust on the internet.
Next Week: Hash Functions & Signatures (Message Authentication)