EUC-EO study plan

Define confidentiality, integrity, availability, authentication, and non-repudiation and match each to a specific cryptographic primitive that provides it

Classify a list of 20 given ciphers as symmetric or asymmetric, block or stream, and identify the key length and block size for each

Explain the difference between confusion and diffusion and identify which operation (substitution vs. permutation) supports each in a substitution-permutation network

Describe the Feistel structure and trace one round of DES encryption given a 64-bit block and a round key, stating where the XOR and the f-function act

Compare AES-128, AES-192, and AES-256 by number of rounds, key schedule, and state size, and state why 128-bit blocks remain adequate

Distinguish ECB, CBC, CFB, OFB, CTR, and GCM by whether they provide parallel encryption, random access to ciphertext, error propagation behavior, and an authentication tag

Explain why ECB mode leaks plaintext structure and construct a concrete scenario where identical plaintext blocks produce identical ciphertext blocks

Describe the CBC IV requirements and explain the consequence of reusing an IV across two messages

Explain how GCM combines CTR-mode encryption with GHASH authentication and state the security rule that a nonce must never repeat under one key

Select an appropriate mode for three given use cases (disk encryption, TLS record protection, encrypting a small config file) and justify each choice

Perform a small RSA key generation by hand with p=61 and q=53, computing n, phi(n), choosing e, and deriving d, then encrypt and decrypt a single numeric message

Explain why RSA-OAEP is required for encryption while raw textbook RSA is deterministic and malleable

Describe Diffie-Hellman key exchange and explain how an active man-in-the-middle defeats it without authentication

Compare RSA, ECDSA, and Ed25519 by key size, signature size, and typical performance characteristics

Outline the lifecycle of a certificate from CSR generation through CA validation, issuance, and revocation, naming the role of the root and intermediate CAs

Differentiate key transport from key agreement and identify which one RSA key wrapping and which one ephemeral Diffie-Hellman represent

Explain perfect forward secrecy and demonstrate why a static RSA key exchange lacks it while ephemeral DH provides it

Compare key storage options (HSM, TPM, OS keychain, encrypted file, smart card) by threat model, exportability, and performance cost

Describe key splitting and secret sharing at a conceptual level and explain how a 3-of-5 threshold scheme protects a root key

Explain key rotation policy design: rotation triggers, overlap windows, and the consequences of retiring a key still used for decryption

Compare SHA-256, SHA-3, and BLAKE2 by construction (Merkle-Damgard vs. sponge) and explain how length-extension attacks affect Merkle-Damgard hashes

Distinguish HMAC from a plain hash of key concatenated with message and explain why the nested construction resists length extension

Explain the difference between a digital signature and a MAC, including which one provides non-repudiation and why

Describe the signature generation and verification process step by step, including what is hashed and what is signed

Explain certificate chain validation, hostname verification, and the specific failures that caused well-known certificate validation incidents

Trace a full TLS 1.3 handshake naming each message, what key material is derived at each step, and which messages are encrypted

Explain how TLS 1.2 differs from TLS 1.3 in round trips, cipher suite negotiation, and static RSA support

Describe IPSec transport versus tunnel mode and identify where AH and ESP sit in the packet and what each protects

Explain SSH host key verification and user authentication methods and why host key pinning matters

Compare S/MIME and PGP by trust model (centralized CA vs. web of trust), key distribution, and typical deployment

Classify attacks as brute force, dictionary, rainbow table, side channel, padding oracle, or meet-in-the-middle and state the countermeasure for each

Explain why salting defeats precomputed rainbow tables and why password hashing needs a deliberately slow KDF such as Argon2 or bcrypt

Describe the birthday bound and estimate collision probability for a 64-bit hash versus a 128-bit hash at a given number of messages

Explain steganography versus encryption: what each hides, and why steganography without encryption fails if the channel is inspected

Compare common data-hiding carriers (LSB in images, appended data after file terminators, whitespace encoding) and state one detection method for each

Recall the key facts of every domain from memory using spaced-repetition review, targeting at least 85 percent accuracy on your own flashcards

Complete two full-length timed practice sets and log every missed question by domain

Re-teach your three weakest sub-topics in writing without notes, then verify against source material

Resolve every logged miss by writing the correct reasoning and the misconception that produced the error

Build a one-page pre-exam summary of the highest-yield facts: mode properties, key sizes, protocol versions, and attack countermeasures