Security · Namaskara

Seedhi baat mein

Aapke har device ka apna ek joda hota hai — ek taala aur ek chaabi. Jab aap message bhejte hain, aapka phone use ek naye, sirf ek baar kaam aane wali chaabi se band karta hai, phir us chaabi ko chat ke har device ke liye alag se band karta hai. Sirf wahi devices khol sakte hain. Aapka phone message par apna nishaan bhi lagata hai, taaki padhne wale ka phone confirm kar sake ki message sach mein aap hi ne bheja tha aur raaste mein kuch badla nahi.

Technical summary

Device keys: key agreement ke liye X25519 aur signatures ke liye Ed25519, device par hi bante hain. Private keys device ki safe jagah mein rehti hain, kabhi upload nahi hoti.
Messages: ek random 256-bit content key, ChaCha20-Poly1305 se message ko band karti hai. Content key ko har recipient device ke liye ephemeral X25519 + HKDF-SHA256 se alag wrap kiya jaata hai. Envelope header (conversation, sender, device, message id, recipient list) associated data ke roop mein juda hota hai aur Ed25519 se sign hota hai.
Files: device par hi ek baar kaam aane wali chaabi se band hoti hain, aur wahi chaabi encrypted message ke andar jaati hai. Server sirf band ki hui file rakhta hai.
Calls: DTLS-SRTP media ke saath WebRTC. Offers, answers aur ICE candidates usi sign kiye aur band envelope mein jaate hain, isliye server call set-up na padh sakta hai, na badal sakta hai.
Safety numbers: dono logon ki device keys ka ek nishaan. Kisi se seedha milkar compare karein taaki pata chale ki beech mein koi aur nahi hai. Jab kisi contact ki keys badlein, app aapko bata deta hai.
Sign-in: scrypt se password hash, optional TOTP two-step verification hashed recovery codes ke saath, 5 galat koshishon ke baad lock-out, 12 ghante ki nishkriyata aur 24 ghante ki adhiktam session, HttpOnly SameSite=Strict cookie. Kahin bhi SMS nahi.
Web: sakht Content-Security-Policy, koi third-party origin nahi, frame mein dikhana band, production mein HSTS.
Android: screen capture rokne ke liye FLAG_SECURE, cleartext traffic band, app backup band.

Server kya dekh sakta hai

Kaun, kisse aur kab baat karta hai, message aur file ka size, group ke naam aur members, aur yeh ki call shuru ho rahi hai. Tasks, agreements aur report drafts server par bina end-to-end suraksha ke rakhe jaate hain. Yeh sab hum Privacy page par khulkar likhte hain.

Hum test kaise karte hain

Har release 40 se zyada automatic jaanchon se guzarti hai, jisme shamil hain: Python mein likha ek alag protocol ka version jo app ke saath kaam kare; tampered, nakli aur dobara bheje gaye envelopes par hamle; server database mein seedhe text ki talash; yeh jaanch ki mitti ho chuke disappearing messages apni keys samet delete hue hain ya nahi; aur browser audit ki web app ne koi bhi third-party request nahi ki.

Jaani hui seemaein

Abhi forward secrecy ratchet nahi hai: chori hui device key se us device ko bheje gaye purane messages padhe ja sakte hain. Double-ratchet design roadmap mein hai.
Metadata server ko dikhai deta hai, jaise upar bataya gaya.
Web version ki security browser par aur hamare server se bheje jaane wale code par depend karti hai. Yahi ek wajah hai ki web version abhi sirf ek chhoti invite-only pilot tak seemit hai: Google Play app pehle aayegi, aur hum uska signing certificate Get Namaskara page par publish karenge.

Security issue report karein

Koi kami mili? Publish karne se pehle hume privately batayein — Contact ke zariye, subject mein "Security" likhkar. Hum jawab denge, theek karenge aur aapko credit bhi denge agar aap chahein. Kripya doosre logon ke accounts par test na karein.