RFR: 8357033: Reduce stateless session ticket size [v9]

[Bradford Wetmore]

On Thu, 22 May 2025 19:23:22 GMT, Artur Barashev <abarashev at openjdk.org> wrote:

>> The stateless session ticket is included in the ClientHello message, either in the stateless_ticket extension (pre-TLS1.3), or in the pre_shared_key extension (TLS1.3). With the current construction, the ticket is often the largest contributor to the ClientHello message size. For example, in HttpClient tests we observed a case where a non-resumption ClientHello occupied 360 bytes, and the session ticket (pre_shared_key identity) included in a resumption ClientHello occupied 1600+ bytes.
>> 
>> ClientHello messages that do not fit in a single packet on the network can greatly increase the handshake time on lossy networks. Ideally we would like the ClientHello message to always fit in a single packet.
>> 
>> When using QUIC as the underlying protocol, one packet can hold approximately 1100 byte payload. Getting the session ticket size below 700 bytes should be sufficient to make the ClientHello fit in a single packet
>> 
>> Things done in this PR to reduce the ticket size in order of importance:
>> 
>> 1. Remove local certificates.
>> 2. Compress tickets with the size 600 bytes or larger.
>> 3. Remove `peerSupportedSignAlgs`.
>> 4. Remove `pskIdentity`
>> 5. PreSharedKey is only needed by TLSv1.3, masterSecret is only needed by pre-TLSv1.3
>> 6. Remove `statusResponses`
>> 
>> Tickets with a chain of 2 RSA peer certificates are still above 700 bytes (about 1KB), but they are significantly reduced from prior size of about 3KB.
>
> Artur Barashev has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Assume "createPossession" can return more certificates than in the session ticket

Will have a look at this hopefully later today.

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PR Comment: https://git.openjdk.org/jdk/pull/25310#issuecomment-2902548217