Post-quantum security for SSH access on GitHub

GitHub is adding a post-quantum secure SSH key exchange algorithm to protect Git data access against future quantum computing threats.

• •The new algorithm, sntrup761x25519-sha512, combines Streamlined NTRU Prime (post-quantum) with classical X25519 elliptic curve Diffie-Hellman for hybrid security
• •This addresses the "store now, decrypt later" attack vector, where encrypted sessions captured today could be decrypted by future quantum computers
• •Rollout begins September 17, 2025 for GitHub.com and non-US GitHub Enterprise Cloud regions; US region is excluded due to FIPS compliance requirements
• •OpenSSH 9.0+ clients will automatically use the new algorithm; older clients fall back gracefully to classical algorithms without disruption
• •HTTPS access and GitHub Enterprise Server (until 3.19) are unaffected; only SSH-based Git connections are impacted