CISSP Crypto: Which Key for Privacy vs Signing?

On the CISSP, you encrypt with the recipient’s PUBLIC key for confidentiality and sign with your OWN PRIVATE key for proof - swapping them is the single most common crypto mistake. This Domain 3 deep-dive walks the cryptography core in plain language, then drills the exact key-choice reflex the exam rewards. With Liam, Erica, Fatima, and Fenrir, we cover symmetric versus asymmetric encryption, hashing, HMAC, digital signatures, and the key lifecycle that protects all of it, anchored to the 2026 exam outline.

In this video:

• Symmetric encryption and why AES is the fast standard for bulk data
• Block cipher modes, the ECB pattern trap, and why GCM adds integrity
• The key-distribution problem and the n times (n minus one) over two formula
• Asymmetric pairs: RSA, Elliptic Curve, and Diffie-Hellman for key exchange
• Which key gives confidentiality versus which key gives a signature
• Hashing properties, HMAC, and how a digital signature delivers all three guarantees

The next video moves into public key infrastructure and the certificate system that makes cryptography trustworthy at scale. Anchored to the (ISC)2 CISSP Detailed Content Outline effective April 15, 2024.

Presented by Professor Erica — CISSP, CISM, PMP, M.S. Project Management, D.B.A. in progress.

▶ Watch next: CISSP Domain 3: PKI, TLS & Crypto Attacks (2026) https://www.youtube.com/watch?v=i2_9fyt9k_s

📺 Full playlist: CISSP (2026) v2 https://www.youtube.com/playlist?list=PLlIAFxS2964_K3g6WysWnLpifoxilduGi