Cloudflare Research: Post-Quantum Key Agreement

On essentially all domains served (1) through Cloudflare, including this one, we have enabled hybrid post-quantum key agreement. We are also rolling out support for post-quantum key agreement for connection from Cloudflare to origins (3). Check out our blog post the state of the post-quantum Internet for more context.

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Deployed key agreements

Available with TLSv1.3 including HTTP/3 (QUIC)

Key agreement TLS identifier
X25519Kyber768Draft00 0x6399 (recommended) and 0xfe31 (obsolete)
X25519Kyber512Draft00 0xfe30
X25519Kyber[x]Draft00 is a hybrid of X25519 and Kyber[x]Draft00 (in that order).

Software support



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