Add HKDF implementation (RFC 5869) to the standard library

[bitmooze]

Feature or enhancement

Proposal:

Proposal: Add HKDF (HMAC-based Extract-and-Expand Key Derivation Function)

Background

HKDF is a widely used KDF defined in RFC 5869. It’s used in TLS 1.3, noise protocols, OAuth token derivation, and many other protocols.

Proposal

Add a pure-Python implementation of HKDF to the standard library:

• Follows RFC 5869
• Supports any hash algorithm in hashlib
• Includes PRK and OKM derivation
• Comprehensive RFC test vectors included

Example

from hkdf import HKDF
okm = HKDF(ikm, salt, hashlib.sha256).derive(length=42, info=b"info")

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

No response

[picnixz]

I prefer leaving this to third party library or at least discuss this on DPO. Sorry