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Ethical Hacking Cryptography Flashcards
60 question-and-answer cards covering Cryptography as it is examined in Ethical Hacking. 24 of them are printed below, taken from across the deck — no signup, no paywall on the preview.
24 sample cards from the Cryptography deck
Sampled from the end of the deck, so these are different cards from the ones shown on the syllabus page.
Name two defenses that make brute-force attacks impractical.
Use large key sizes (e.g., 256-bit keys), and add rate limiting, account lockouts, or slow key-derivation functions (e.g., bcrypt, PBKDF2, Argon2) to increase per-guess cost.
What is cryptanalysis?
The study of analyzing and breaking cryptographic systems to recover plaintext or keys without being given the key, by exploiting weaknesses in the algorithm or implementation.
Differentiate a known-plaintext attack from a chosen-plaintext attack.
In a known-plaintext attack the analyst has some plaintext-ciphertext pairs. In a chosen-plaintext attack the analyst can pick arbitrary plaintexts and obtain their ciphertexts, giving more power to deduce the key.
What is a ciphertext-only attack?
The weakest attack model, where the cryptanalyst has access only to ciphertext (no plaintext) and tries to recover the key or plaintext, often using statistical/frequency analysis.
What is a side-channel attack? Give an example.
An attack that exploits physical information leaked during computation rather than mathematical weaknesses. Examples: timing analysis, power consumption analysis, electromagnetic emissions, or acoustic leakage.
What is a birthday attack and which property does it threaten?
An attack exploiting the birthday paradox to find hash collisions: for an $n$-bit hash, a collision is expected after about $2^{n/2}$ trials, threatening collision resistance.
What is a Man-in-the-Middle (MITM) attack?
An attack where the attacker secretly relays and possibly alters communication between two parties who believe they are talking directly, intercepting or modifying messages in transit.
Why is plain (unauthenticated) Diffie-Hellman vulnerable to a MITM attack?
Because it exchanges public values without authenticating identities, an attacker can establish separate shared keys with each party and relay messages, decrypting and re-encrypting them undetected.
Name two defenses against Man-in-the-Middle attacks.
Use authentication via digital certificates/PKI (e.g., verifying TLS certificates), and use authenticated key exchange, certificate pinning, or mutual authentication to bind identities to keys.
What is Public Key Infrastructure (PKI)?
The framework of hardware, software, policies, and roles (certificate authorities, registration authorities, certificates) that creates, manages, distributes, and revokes digital certificates to bind public keys to verified identities.
What is the role of a Certificate Authority (CA) in PKI?
A trusted third party that verifies an entity's identity and issues a digitally signed certificate binding that identity to its public key, allowing others to trust the key.
What is contained in an X.509 digital certificate?
It contains the subject's identity, the subject's public key, the issuing CA, validity period (not-before/not-after dates), serial number, and the CA's digital signature over the certificate.
How is a certificate revoked in PKI, and name the two main mechanisms.
A CA revokes a compromised or invalid certificate before expiry. Clients check status via a Certificate Revocation List (CRL) or the Online Certificate Status Protocol (OCSP).
What is a chain of trust in PKI?
A hierarchical path of certificates from a trusted root CA through intermediate CAs down to the end-entity certificate, where each certificate is signed by the one above it, so trust in the root extends to the leaf.
What is a digital signature and what does it provide?
A cryptographic value created by signing a message's hash with the sender's private key. It provides authentication, data integrity, and non-repudiation.
Describe the process of creating a digital signature.
The signer computes a hash of the message, then encrypts (signs) that hash with their private key. The signature is sent alongside the message.
How is a digital signature verified?
The verifier decrypts the signature with the sender's public key to recover the original hash, independently hashes the received message, and checks that the two hashes match. A match confirms authenticity and integrity.
Why does a digital signature use the private key, while confidentiality encryption uses the public key?
Signing uses the sender's private key so anyone can verify with the public key (proving origin). Confidentiality encrypts with the recipient's public key so only the recipient's private key can decrypt (proving secrecy).
Why is the message hashed before signing rather than signing the whole message?
Signing a small fixed-size hash is far more efficient than signing large data with slow asymmetric operations, and the hash's collision resistance still binds the signature to the exact message content.
What is the difference between SSL and TLS?
TLS (Transport Layer Security) is the modern successor to the now-deprecated SSL (Secure Sockets Layer). TLS is more secure; SSL versions are obsolete though 'SSL' is still used colloquially.
What security services does SSL/TLS provide?
Confidentiality (encryption of data in transit), integrity (via MACs/AEAD), and server (and optionally client) authentication using digital certificates.
Outline the main steps of the TLS handshake.
Client and server exchange hellos (agreeing on cipher suite and random values), the server presents its certificate, they perform key exchange to derive a shared session key, verify each other, and then switch to encrypted symmetric communication.
How does TLS use both asymmetric and symmetric cryptography?
It uses asymmetric cryptography (certificates and key exchange like RSA or ECDHE) during the handshake to authenticate and establish a shared session key, then uses fast symmetric encryption (e.g., AES) for the actual data transfer.
What is forward secrecy (Perfect Forward Secrecy) in TLS?
A property where ephemeral session keys are used (e.g., via ephemeral Diffie-Hellman, ECDHE) so that compromise of the server's long-term private key does not allow decryption of previously recorded sessions.
What this deck covers
The Cryptography deck follows the Ethical Hacking Cryptography syllabus — 4 chapters and 12 topics — so questions land on material that is genuinely examinable rather than trivia around it. That works out to roughly 15.0 cards per chapter.
Answers are written to be recallable, not just readable — averaging about 194 characters, which is long enough to carry the reasoning and short enough to say out loud.
A deck like this earns its keep on the second and third pass. Read the syllabus first so you know the shape of the subject, then use the cards to find the specific facts that have not stuck.
Cryptography flashcards FAQ
How many Cryptography flashcards are in this Ethical Hacking deck?
60 cards. This page previews 24 of them, sampled evenly across the deck so you can judge the difficulty before installing anything.
Are these Ethical Hacking flashcards free?
Yes. The preview here is free to read with no signup, and the full 60-card deck is free inside the Examius app.
What do the Cryptography cards cover?
They follow the Ethical Hacking Cryptography syllabus — 4 chapters and 12 topics — so the questions track what is actually examinable.
How should I use these flashcards?
Read the syllabus first so you know the shape of the subject, then drill the deck. Examius schedules each card with spaced repetition, so cards you keep missing come back sooner and ones you know drift further apart.