Cryptographic Techniques and Trends Questions

Broad knowledge of contemporary and emerging cryptographic primitives, protocols, and research directions. Includes understanding of authenticated encryption with associated data and why it is preferred over legacy constructions, password based key derivation functions such as PBKDF2, Argon2, and scrypt and the role of salting and key stretching, elliptic curve cryptography design and trade offs, and an awareness of post quantum cryptography candidates including lattice based, multivariate, and hash based approaches. Also encompasses familiarity with the modern threat landscape such as quantum computing risks, how cryptographic research progresses into standards and real world practice, how to follow relevant conferences and journals, and the ability to synthesize research findings into practical recommendations for design, migration, and policy decisions.

HardTechnical

105 practiced

Develop a methodology for selecting parameters for lattice-based KEMs to achieve approximately 128-bit classical security with a conservative post-quantum margin. Describe metrics and models to estimate security (e.g., BKZ cost models), which parameters to vary (dimension, modulus, error distribution), simulation/testing approaches to validate assumptions, and how to balance key/ciphertext sizes versus computational performance.

EasyTechnical

90 practiced

List the key conferences, workshops, and journals you would monitor to stay current in cryptographic research (classical and post-quantum). Propose a realistic monitoring workflow (weekly/monthly) including which sources you would subscribe to, how you would triage papers, and how you would decide whether a result requires a change in production cryptographic decisions.

EasyTechnical

81 practiced

Define the security notions IND-CPA and IND-CCA for encryption schemes, explaining the attacker capabilities under each model and the type of oracle access assumed. Give an example of an encryption scheme that is IND-CPA secure but not IND-CCA secure, and explain why the stronger IND-CCA notion matters in protocol engineering.

HardSystem Design

127 practiced

Design the cryptographic architecture for a high-throughput VPN targetting ~100 Gbps aggregate throughput with many short-lived sessions. Choose cipher suites (AEAD choices), handshake mechanisms, KDF and session-resumption strategies, and describe how to leverage hardware acceleration (NIC offload, AES-NI, vectorized implementations). Provide a realistic benchmarking and instrumentation plan to validate throughput, latency, and connection setup performance under load.

EasyTechnical

91 practiced

Compare PBKDF2, bcrypt, scrypt, and Argon2 at a high level. For each describe its primary design goals, whether it is CPU-bound or memory-hard, how resistant it is to GPU/ASIC acceleration, and any known side-channel concerns. For a greenfield web service today, state which you would choose by default and justify that choice in terms of security and deployability.

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