How do you decrypt TLS traffic in Wireshark to inspect application data?

• A. Provide the appropriate keys via SSLKEYLOGFILE or pre-master secret; Wireshark will decrypt and show the plaintext in TLS streams
• B. Use a decryption plugin
• C. Attempt to decrypt offline with a custom tool
• D. TLS cannot be decrypted in Wireshark

Answer: (A)

Decrypting TLS in Wireshark hinges on having the session keys that protected the traffic. TLS uses per-session encryption derived from handshake secrets, so without those keys the payload remains unreadable.

The practical way to get those keys is to have the client write them to a log file during the handshake. Most browsers can do this by setting an environment variable like SSLKEYLOGFILE (pointing to a file) before you start the browser. Wireshark then uses that key log to derive the same encryption keys for the captured sessions and can display the plaintext inside TLS streams. In Wireshark, you can specify the path to the key log file (or set the environment variable) and then, after capturing the TLS handshake, open a TLS stream and you’ll see the decrypted application data when you “Follow TLS stream” or inspect the TLS dissector output.

This approach directly uses the needed keys to decrypt, which is why it’s the correct method. Using a decryption plugin, attempting offline decryption with a custom tool, or assuming TLS cannot be decrypted aren’t standard, reliable methods in typical Wireshark workflows.