RFC 6066 Quiz

Q1: Which record-layer behavior follows from this handshake?

Multiple Choice

A TLS 1.2 client offers `truncated_hmac`. The server completes a full handshake but does not include `truncated_hmac` in ServerHello. The selected cipher suite uses HMAC.

A. Abort, because a server must accept every RFC 6066 extension offered by a client B. Continue without truncation; the client offer alone did not negotiate 80-bit HMAC tags C. Send truncated tags because ClientHello unilaterally changes both record layers D. Treat the missing echo as proof that the server resumed a previous session

**Explanation:** RFC 6066 Section 7 says a server MAY agree by including the extension in ServerHello; only after successful negotiation MUST both sides use 10-byte HMAC tags. B follows that state. A turns an optional offer into a requirement. C ignores server acceptance. D is unsupported because extension absence in a full handshake does not prove resumption.

Q2: What may the client conclude when no stapled status arrives?

Multiple Choice

A client offers `status_request` and requires OCSP validation by local policy. A server with an otherwise acceptable certificate completes the handshake without negotiating the extension or sending CertificateStatus.

A. The certificate is not revoked because absence of CertificateStatus is a positive status result B. The server violated RFC 6066 because it was required to accept the client's request C. Stapled status is unavailable; the client should contact OCSP directly or abort under its requirement D. The client may authorize the peer first and validate status only after the protected operation

**Explanation:** Section 8 lets a server decline to provide CertificateStatus, while Section 11.6 warns that a compromised-key server can pretend not to support the extension. C preserves the unknown status and applies the client's requirement. A invents positive evidence. B turns MAY into MUST. D is a fail-open policy contrary to the premise; RFC 6066 does not make authorization precede required validation.

Q3: Which HostName value is correctly encoded for SNI?

Multiple Choice

A client connects to the internationalized DNS name “bücher.example” and constructs RFC 6066 `server_name`.

A. `bücher.example.` as raw UTF-8, retaining the trailing dot B. `xn--bcher-kva.example` as an ASCII A-label without a trailing dot C. `[2001:db8::1]` as an ASCII IPv6 literal for the same endpoint D. Both the Unicode name and A-label as two `host_name` entries in one list

**Explanation:** Section 3 defines HostName as an ASCII fully qualified DNS name without a trailing dot and uses A-labels for internationalized names, so B is correct. A violates encoding and dot rules. C is a literal address, which is prohibited. D violates the requirement that ServerNameList contain at most one name of each name_type.

Q4: How must the client handle this max-fragment response?

Multiple Choice

A client requests `max_fragment_length` 2^10. The ServerHello includes the extension but returns 2^11, intending to choose a nearby supported limit.

A. Accept 2^11 because the server may select any allowed value B. Abort with `illegal_parameter` because the response differs from the requested value C. Use the smaller local limit while treating negotiation as successful D. Ignore only the response extension and continue as though the server had sent none

**Explanation:** Section 4 permits the server to accept by echoing the same value; a different response value requires the client to abort with `illegal_parameter`, so B is correct. A invents server selection. C creates inconsistent record limits. D ignores a malformed negotiation response instead of the specified fatal behavior.

Q5: Which gateway decision follows RFC 6066's name-consistency rule?

Multiple Choice

A gateway receives SNI `agents.example`, selects that virtual host's certificate, and completes TLS. The protected HTTP request then carries authority `billing.example`. The gateway's routing policy assumes the two names are identical.

A. Route to billing because the protected authority always overrides the earlier SNI without comparison B. Route to agents because SNI authenticates the client's identity and requested operation C. Detect the mismatch and apply defined routing policy before dispatch; SNI is not client authorization D. Accept either route because successful TLS proves that all names inside the connection are equivalent

**Explanation:** Section 11.1 requires an application server that relies on the names being the same to check that the client did not present a different application-protocol name. C performs that check and keeps authorization separate. A omits the required comparison. B misuses a server-routing hint as client identity and permission. D confuses channel protection with semantic equality.

Q6: Which resumption review is correct?

Multiple Choice

A full TLS 1.2 session negotiated `max_fragment_length` 2^10 and `truncated_hmac`. A later ClientHello requests resumption and repeats both offers. The server resumes the session and omits both extensions from ServerHello. The client resets to 2^14 fragments and full HMAC.

A. The server omission is required, but the client is wrong: the original session's negotiated functions apply to the resumed session B. The server must echo both extensions on resumption, and the client is right to reset until it does C. The client must omit all extensions when requesting resumption, so neither side can apply the original functions D. Resumption preserves only the fragment limit; HMAC truncation must always be renegotiated

**Explanation:** Section 1.1 says that on accepted resumption the server MUST ignore these extensions and send none of them, while the functionality negotiated at original initiation applies to the resumed session. Sections 4 and 7 specifically say both functions last through resumptions, so A is correct. B demands a forbidden echo. C contradicts the client's SHOULD and loses fallback behavior if resumption is denied. D invents unequal lifetime rules.

TLS Extensions

References (URLs)

Q1: Which record-layer behavior follows from this handshake?

Q2: What may the client conclude when no stapled status arrives?

Q3: Which HostName value is correctly encoded for SNI?

Q4: How must the client handle this max-fragment response?

Q5: Which gateway decision follows RFC 6066's name-consistency rule?

Q6: Which resumption review is correct?