AI & Technical question

Design a hash function.

Practice this question out loud. An AI interviewer asks it, follows up like a real interviewer would, and scores your answer. Type or speak.

What this question tests

Technical fundamentals: explaining what a hash function does, its key properties, and why they matter for real systems.

Define a hash function: it maps input data of any size to a fixed-size output deterministically.
Explain the key properties needed: deterministic output, fast computation, uniform distribution, and collision resistance.
Give a concrete use case relevant to a PM role, like deduplicating records or verifying data integrity in an API.
Explain the trade-off between speed and collision resistance, comparing a simple checksum to a cryptographic hash like SHA-256.
Note when to use each type, such as a fast non-cryptographic hash for deduplication versus cryptographic hashing for security.

Explains the deterministic, fixed-size, uniform-distribution properties clearly rather than a vague definition.
Gives a concrete example relevant to product work, like using a hash to detect duplicate uploaded files.
Distinguishes cryptographic hashes (for security, like password storage) from simple hashes (for speed, like caching keys).
Notes collision handling as a real design consideration, not an edge case to ignore.

Confusing hashing with encryption, which is reversible and serves a different purpose.
Giving no concrete use case, keeping the explanation purely academic.
Ignoring collision resistance as a meaningful property.

Chapters of the AI PM course that teach what this question tests.