Cryptography & Data Protection Flashcards

What is the role of a Certificate Authority (CA) in SDL's use of Public Key Infrastructure (PKI)?

Answer: To issue, sign, and revoke digital certificates that bind public keys to identities

A CA is a trusted third party that issues and digitally signs certificates, establishing the binding between a public key and the entity's identity.

In SDL, which password hashing algorithm is preferred over bcrypt for resistance to GPU-based and memory-constrained hardware attacks?

Answer: Argon2id

Argon2id (the winner of the Password Hashing Competition) is memory-hard, making it resistant to GPU and ASIC attacks; it is the current SDL recommendation.

What SDL mechanism is used to detect whether encrypted data has been tampered with before decryption occurs?

Answer: Authenticated tag verification in AEAD modes

AEAD modes produce an authentication tag; if the ciphertext or associated data has been tampered with, tag verification fails before any decryption takes place.

Which SDL practice is designed to ensure that decrypted data is not held in memory longer than necessary?

Answer: Secure memory zeroing / wiping after use

SDL requires that sensitive plaintext be zeroed out (overwritten) in memory immediately after use to minimize the window during which it could be read by an attacker.

What does 'perfect forward secrecy' (PFS) provide in an SDL-compliant TLS configuration?

Answer: Guarantees that past session keys cannot be derived even if the server's long-term private key is later compromised

PFS uses ephemeral key exchange (ECDHE/DHE) so that each session's key is independent; compromise of the server's long-term key does not expose past session traffic.

In SDL, what is the purpose of 'envelope encryption' in a cloud key management system?

Answer: Encrypting data with a data encryption key (DEK) and then encrypting the DEK with a key encryption key (KEK)

Envelope encryption encrypts data with a DEK, then encrypts the DEK with a KEK stored in a KMS; only the small DEK needs to transit the KMS, improving performance and control.

According to SDL guidelines, which practice should be applied when generating cryptographic nonces or IVs to prevent predictability attacks?

Answer: Use a cryptographically secure pseudo-random number generator (CSPRNG)

CSPRNGs produce unpredictable values suitable for cryptographic purposes; using predictable or reused IVs can break the security of block cipher modes like CBC or CTR.