OpenSSH Hybrid KEX

OpenSSH's default key exchange went post-quantum in 2022 — earlier than any browser — using Streamlined NTRU Prime.

Core Principles & Analysis

• OpenSSH 9.0 made sntrup761x25519 the default key exchange in April 2022.
• The project cited harvest-now-decrypt-later explicitly as the rationale for moving early.
• OpenSSH 10.0 switched the default to the standardized ML-KEM hybrid in 2025.

Specifications & Metrics

• PLATFORM: OpenSSH
• MECHANISM: sntrup761x25519 → mlkem768x25519
• SINCE: 2022