Which scenario best indicates a cipher suite is obsolete for current clients?

• A. The cipher suite is only available in TLS 1.3
• B. The cipher suite uses TLS 1.0 only
• C. The cipher suite is widely supported by modern browsers
• D. The cipher suite is no longer supported by major browsers and security standards

Answer: (D)

The main idea here is that obsolescence is driven by whether modern clients and security standards actually support and enforce using a cipher suite. When a cipher suite is no longer supported by major browsers and is deprecated or dropped by security standards, there’s no practical path for clients to negotiate it during a TLS handshake. In other words, even if a server offers it, clients won’t use it, so it’s effectively obsolete.

That’s why the scenario where major browsers and security standards no longer support the cipher suite is the best indicator of obsolescence. It signals a broad, real-world lack of compatibility and a push to move away from the suite for security reasons. In contrast, a suite that’s only available in TLS 1.3 isn’t automatically obsolete—TLS 1.3 itself is modern, and those suites can still be current if clients actually support TLS 1.3. A suite limited to TLS 1.0 or one that’s widely supported by modern browsers would not indicate obsolescence. Only when the suite is dropped by major browsers and standards bodies does it become effectively unusable in practice.