On Thu, Sep 16, 2021 at 04:57:03PM +0200, Hubert Kario wrote: > On Thursday, 16 September 2021 16:28:47 CEST, Benjamin Kaduk wrote: > > On Thu, Sep 16, 2021 at 04:11:49PM +0200, Hubert Kario wrote: > > > On Thursday, 16 September 2021 04:41:44 CEST, Jaya Muthiah wrote: > > > > > > > > I am trying to get the remaining lifetime of the ticket so that server > > > > can decide to renew ticket or not > > > > > > TLS 1.3 tickets are single use. If the ticket was used by a client, and > > > you expect it to make a connection in the future, server needs to > > > send a new > > > one. > > > > Single-use tickets are only a protocol requirement when 0-RTT data is used. > > The OpenSSL implementation even allows the libssl-internal enforcement of > > single-use to be disabled (see SSL_OP_NO_ANTI_REPLAY at > > https://urldefense.com/v3/__https://www.openssl.org/docs/manmaster/man3/SSL_CTX_set_options.html__;!!GjvTz_vk!GxR4URFTB0lwkM5nlYZdtn3DUdeaujsu1sHMYc_nRTUpkmLQP8-zz_b4HS_rcA$ ). > > OpenSSL as a client also has some measures to encourate single-use tickets, > > which I have a PR open to provide a knob to disable: > > https://urldefense.com/v3/__https://github.com/openssl/openssl/pull/16598__;!!GjvTz_vk!GxR4URFTB0lwkM5nlYZdtn3DUdeaujsu1sHMYc_nRTUpkmLQP8-zz_YPrcg6yw$ . > > They're single use not only because of replay but also because of privacy > reasons, as reuse of a ticket indicates that the same client did send it. Yes. But the protocol itself only encourages single-use for privacy reasons. The protocol does not *require* single-use in that case. -Ben
