Tacendum — Private Messaging

Private conversations without the crowd. End-to-end encrypted chats, rooms of up to twelve, and calls. No phone number or email required, no directory, no ads.

Some conversations are just between the people in them.

Tacendum is end-to-end encrypted messaging, rooms and calls for iPhone. There is no sign-up: no phone number, no email, no username, no password required. A key created on your phone the first time the app opens is the account. Nobody can look you up unless you choose it — there is no directory and no search. You hand your ID to someone yourself, normally by scanning a code in person; or link an email or a username in Settings, switch on findability, and someone who already knows it can find you. Each is optional and revocable, and none becomes a login.

WHAT IT DOES

— One-to-one chats, encrypted end to end with the Signal protocol (libsignal). Edit a message, delete it for everyone, reply, react, mention someone by name. Send photos, files, voice notes, or a place you have chosen to share.

— Rooms: one conversation for up to twelve people. Only the person who made a room can add or remove anyone, and only they can hand a new arrival the history from before — deliberately, and the room is told when they do. Every room message is encrypted separately for every member; the room's name and everything said in it are hidden from us.

— Calls: one-to-one voice and video, end-to-end encrypted, with the set-up riding inside the same encrypted envelope as a message. A room can hold a voice call of up to six people. The first call with someone new is relayed by default, so a stranger does not learn your IP address; one switch keeps every call that way.

— Disappearing messages, with a timer you choose per conversation.

— Screenshots are disclosed, always. iPhones do not let any app block a screenshot, so instead of pretending, Tacendum tells: take one inside a conversation and the other person is told, in that conversation. No setting turns that off. While the screen is being recorded, mirrored or AirPlayed, conversations are hidden until it stops.

— Safety numbers. Every pair of people has one number, and both see the same one. If someone's key changes, Tacendum stops and says so before you send anything else.

— App lock: a passcode on top of the phone's own, with an auto-lock delay. One code, two doors — your code opens your conversations, and the same code entered backwards opens a decoy instead: invented people, unreadable messages, while the real ones stay sealed. There is no second secret to remember or to be made to give up.

— Blocking and reporting. Blocking is yours alone and invisible to the blocked. Reporting sends us only what you explicitly select, and the report screen says exactly what leaves your phone.

WHAT ISN'T THERE

No feed. No directory. No ads, no trackers. The app never asks for your contacts — there is no address-book upload. No archive: your history lives on your phone and nowhere else, and undelivered ciphertext clears from our servers within thirty days. And no recovery of messages or keys, by design: the key never leaves your phone, so if you lose the phone, its history is gone. A linked email can win back only which devices are yours and whether you can be found — never a message. We cannot restore the rest — that is the point.

WHAT ENCRYPTION DOESN'T COVER

Encryption hides what you said, not that you said it. Who each room message goes to is visible to us, and the privacy policy at tacendum.com/privacy says exactly what our servers can still see. We would rather tell you than have you assume.

SOURCE

Tacendum is free software under the AGPL-3.0 license. The complete Corresponding Source for this exact build is published at github.com/MiranaTechs/Tacendum, tag v1.0-b24.

Tacendum requires iOS 15.1 or later. Terms: tacendum.com/terms. Privacy: tacendum.com/privacy. Support: tacendum.com/support or hello@tacendum.com.