diff --git a/draft-ietf-tls-tls13.md b/draft-ietf-tls-tls13.md index ef0b447f2..82c25200c 100644 --- a/draft-ietf-tls-tls13.md +++ b/draft-ietf-tls-tls13.md @@ -3321,7 +3321,6 @@ ticket_lifetime for a shorter period of time than what is stated in the ticket_lifetime. - ticket_age_add : A securely generated, random 32-bit value that is used to obscure the age of the ticket that the client includes in the "pre_shared_key" extension. @@ -3334,7 +3333,6 @@ The ticket itself is an opaque label. It MAY either be a database lookup key or a self-encrypted and self-authenticated value. Section 4 of {{RFC5077}} describes a recommended ticket construction mechanism. - extensions : A set of extension values for the ticket. The "Extension" format is defined in {{extensions}}. Clients MUST ignore @@ -3353,6 +3351,15 @@ max_early_data_size SHOULD terminate the connection with an "unexpected_message" alert. {:br } +Note that in principle it is possible to continue issuing new tickets +which continue to indefinitely extend the lifetime of the keying +material originally derived from an initial non-PSK handshake (which +was most likely tied to the peer's certificate). It is RECOMMENDED +that implementations place limits on the total lifetime of such keying +material; these limits should take into account the lifetime of the +peer's certificate, the likelihood of intervening revocation, +and the time since the peer's online CertificateVerify signature. + ### Post-Handshake Authentication The server is permitted to request client authentication at any time