Yes, anyone who analyzes the messages you send can assume that you are using SMSSecure. However, compared to the amount of metadata that's already being leaked

Yes, anyone who analyzes the messages you send can assume that you are using SMSSecure. However, compared to the amount of metadata that's already being leaked over SMS[1], adding the fact that you could[2] be using a specific SMS client that has the ability to encrypt messages doesn't seem too bad. There was an option in a previous version of TextSecure to disable this tagging, but it was deemed unused and axed[3]. For the same reason, I'm loathe to add it back in, but having the option shoved under the "Advanced" menu may not be too bad. [1] This is something that TextSecure does much better with. SMS messages (even encrypted) still leak metadata on who you're messaging and when. [2] There's some element of deniability with whitespace tags (granted, not a lot). On the other hand, if you're registered with TextSecure (which can be checked simply by adding a user your contacts and opening the app), there's only one reason you would be there. [3] See https://github.com/WhisperSystems/TextSecure/commit/40eca5e0f600f0579c8e4001da74d19b8785e820 https://github.com/WhisperSystems/TextSecure/commit/40eca5e0...