Which keys are necessary to decrypt Application data in a SSL connection? I'm debugging an application which communicates between client and server using a SSL/TLS connection, and want to capture and analyze the sent data.

Are the client write keys and server write keys enough to decrypt the data, or do we also need the MAC keys?
To simply decrypt the data, the keys that were used to encrypt it are all you need.

However without the MAC keys you won't be able to verify the integrity of a message, so you won't be able to tell if the data you have decrypted is the same as what was sent (or even who sent it).

If you're debugging on a trusted local network then that might not be too important.