Typorithm · medium

Core Concepts They Ask

interview-conceptssecurityinterviewconceptsfundamentals

Saved on this device

Full lesson · 8 learning steps Open any exercise for focused practice

Step 1 of 8 · intro card

Learn Core Concepts They Ask

Security Interview

Interviewers probe fundamentals: define the CIA triad, contrast one-way hashing with reversible encryption, distinguish symmetric (shared secret) from asymmetric (key pair), explain the TLS handshake, and know why passwords are salted before hashing.

The CIA triad — Confidentiality, Integrity, Availability — is the framing for almost every security control, so be ready to define it and give an example of each.

Know the difference between hashing and encryption: hashing is a one-way function with no key (used for integrity and password storage), while encryption is reversible with a key. Symmetric encryption shares one secret key; asymmetric encryption uses a public/private key pair.

The TLS handshake authenticates the server with a certificate, then both sides derive symmetric session keys used for the bulk of the connection. Passwords are stored as salted hashes — a per-password random salt stops rainbow tables and ensures equal passwords hash to different values.

CIA triad: Confidentiality, Integrity, Availability.

Hashing is one-way; encryption is reversible with a key.

Salt is per-password random data, added before hashing.

concepts:
  cia_triad: confidential-integrity-available
  hashing_vs_encryption: oneway-vs-reversible
  symmetric_vs_asymmetric: shared-vs-keypair
  tls_handshake: cert-then-session-keys
  salting: per-password-random

Read the implementation

Connect each part of the code to the concept before you type.

1. CIA triad

Confidentiality, Integrity, and Availability are the three goals every control protects.

cia_triad: confidential-integrity-available

2. Hashing vs encryption

Hashing is one-way (no key, cannot be reversed); encryption is reversible with a key.

hashing_vs_encryption: oneway-vs-reversible

3. Key types

Symmetric uses one shared secret; asymmetric uses a public/private key pair.

symmetric_vs_asymmetric: shared-vs-keypair

4. TLS handshake

TLS authenticates with a certificate, then negotiates symmetric session keys for the actual traffic.

tls_handshake: cert-then-session-keys

5. Salting

A unique random salt per password defeats rainbow tables and makes identical passwords hash differently.

salting: per-password-random

A complete learning loop

Understand

Read the concept map and follow the code breakdown.

Reconstruct

Type the implementation, repair mistakes and work through every recall exercise.

Verify

Use the final check without hints; revisit weak concepts in short practice sessions.