Dap turns a real, in-person handshake — a dap — into cryptographic trust. Two phones face each other, keys move directly between them by camera, and from then on you know exactly who you're talking to. No phone numbers to trust, no server to trust for identity.
Most messengers ask you to trust a phone number or the server's word for who someone is. Dap's organizing idea is simpler and stronger: the dap.
When you're together, both phones exchange key material directly, camera to camera. That direct exchange pins the contact's key in place.
Every later message rides the session set up in that exchange, and a different key can never quietly take the contact's place.
Can't meet? You can still add someone by link — Dap just labels that contact honestly as a lower trust tier, so you always know which contacts are dap-verified.
Every one-to-one conversation uses DSP1 — Dap's own end-to-end protocol, built on standard, audited cryptographic primitives. Group chats use a separate Dap protocol built on the same primitives.
Every session starts with a hybrid handshake — X25519 plus ML-KEM-1024 (FIPS 203) — so a one-to-one conversation stays private even against a future quantum adversary that harvests today's traffic.
Dap's hybrid Double Ratchet gives every message its own keys, so a key stolen today can't unlock one-to-one messages captured earlier in transit — whatever the contact's tier.
There is no sign-up: no phone number, no email, no account. Encrypted envelopes are left at anonymous mailbox addresses.
Dap's relay is a blind mailbox. It holds sealed envelopes until the other phone collects them — and it is built so that even we, or anyone who seizes it, can't read what you send.
Sealed ciphertext it has no key for, its size and timing, the anonymous mailbox addresses it's left in, and your phone's push token if you turn notifications on. When you add someone by link, your first message to them also shows it your public key and display name. More in our privacy policy.
Your messages. Your phone number or email — Dap never has them, because there is no account.
A push notification is a fixed, content-free alert — never who, what, or how much. Your phone wakes and pulls the sealed envelope itself.
Confidentiality and forward secrecy are the same on every one-to-one chat. The colour tells you how a contact was added — by link or in person — and whether you both chose to keep the chat off backups. It's a provenance label, never a traffic light.
Read-once and after-view timers, set per message by the sender.
End-to-end encrypted group chats with a per-viewer trust tier — a member you haven't added yourself is flagged, never hidden.
Set a PIN (or, on iPhone, a graphical unlock), with an optional recovery code. With app lock on, your keys and messages are sealed at rest with AES-256-GCM-SIV.
Built for the device you carry, where the in-person handshake happens.