Encryption
How PinkyBond encrypts messages and calls
Everything she shares with you is encrypted on her phone and decrypted on yours. Our server forwards sealed envelopes it cannot open. We never hold the key.
Built on platform cryptography
We did not write our own crypto. On iPhone we use Apple's CryptoKit. On Android we use Google's Tink. Curve25519 key agreement, HKDF-SHA256 and AES-256-GCM on both, pinned to each other by shared test vectors, so an iPhone and an Android phone produce byte-for-byte identical ciphertext.
Key agreement
Curve25519 (X25519) ECDH
Encryption
AES-256-GCM
Key derivation
HKDF-SHA256
What we do, and what we don't
Every row is checkable. The last three are where we fall short of the best messengers, and we would rather you read that here than find it out later.
| Dimension | PinkyBond |
|---|---|
| Encryption | AES-256-GCM, end-to-end between the two phones |
| Key agreement | Curve25519 (X25519) ECDH, then HKDF-SHA256 |
| Implementation | Apple CryptoKit on iPhone, Google Tink on Android — byte-for-byte interoperable |
| Key storage | iOS Keychain / Android Keystore, hardware-backed where available |
| Pairing | QR code in person, or a 6-character code / link exchanged remotely; both public keys exchanged |
| Verification | A 6-digit code on both phones confirms no one sat in the middle |
| Account | None — no phone number, no email, no password |
| Dostop strežnika do vsebine sporočil in klicev | Nobenega. Ključa nikoli ne hranimo. |
| What the relay stores | ID povezave, vrsta sporočila, časovni žig, velikost, šifrirano besedilo — izbrisano takoj po dostavi, največ 30 dni |
| Fotografije, videoposnetki in datoteke | Do 2 GB, zapečateno z novim ključem za vsako datoteko, ki ga imata samo vidva telefona; izbrisano takoj po prenosu, največ 30 dni. Za partnersko aplikacijo, ki še ni posodobljena: do 25 MB pod ključem povezave, hranjeno 30 dni |
| Dnevnik klicev | Kateri telefon je klical, kdaj, glasovni ali video klic, izid in trajanje — berljivo za naš strežnik, hranjeno 90 dni, izbrisano, ko prekineta povezavo. Nikoli zvok ali slika. |
| Push notifications | Carry no text; the phone decrypts locally |
| Safety Mode | Yes — her phone sends neutral substitute data instead of her real status. Your app shows no indicator, though the flag itself is in the snapshot. |
| Forward secrecy | No — one key per pairing |
| Open source | No |
| Independent audit | Not yet |
How pairing works
No phone number. No email. No account. In the same room, she shows a QR code and you scan it. Apart, she sends you a 6-character code or a link. Either way both phones exchange public keys, derive the same secret, and show a 6-digit verification code so the two of you can confirm no one sat in the middle.
She taps “Pair with partner” in PinkyBloom
Her phone generates a Curve25519 key pair (Apple CryptoKit on iPhone, Google Tink on Android)
She shows a QR code, or sends you a 6-character code or link if you are apart
You scan or enter it in PinkyBond, and your phone generates its own key pair
Your public key travels back to her the same way; both phones now hold both public keys
Each phone runs ECDH and HKDF-SHA256 to derive the same shared secret — nothing secret crosses the network
The shared secret is stored in the iOS Keychain or the Android Keystore
A 6-digit verification code appears on both phones; if they match, no one sat in the middle
The Blind Relay
Naš strežnik je poštni predal za zapečatene ovojnice. Šifrirano besedilo hrani le, dokler ga drugi telefon ne prevzame, nato ga izbriše — najkasneje po 30 dneh, če ta telefon ostane brez povezave. Ključa nima nikoli. Potisna obvestila ne vsebujejo besedila; telefon dešifrira lokalno.
PinkyBloom
Encrypts on her phone
Blind Relay
Šifrirano besedilo hrani do dostave, največ 30 dni
Cannot decrypt
PinkyBond
Decrypts on your phone
Vse, kar naš strežnik shranjuje o sporočilu, datoteki in klicu:
pairingId
Identifier for the pairing; not a name, number or email
senderRole
Which app sent it: PinkyBloom or PinkyBond
messageType
Kakšna vrsta ovojnice je to — na primer klepetalno sporočilo, posnetek stanja, potrdilo ali vzpostavitev klica — nikoli, kaj je notri
timestamp
When it was sent
ciphertext
AES-256-GCM blob we cannot open; its length is the only thing we can measure
retention
Izbrisano takoj, ko ga drugi telefon prejme; največ 30 dni, če ostane brez povezave
relayReceipts
Po dostavi zapis brez vsebine: katero sporočilo je bilo in ali je bilo dostavljeno ali je poteklo. Hranjeno 30 dni, da lahko telefon pošiljatelja pokaže „ni dostavljeno”
mediaObjects
Fotografije, glasovna sporočila, videoposnetki in datoteke do 2 GB, shranjeni na Cloudflare R2 kot šifrirano besedilo pod novim ključem za vsako datoteko, ki potuje samo znotraj šifriranega sporočila. Izbrisano, takoj ko ga telefon tvoje partnerke prenese; največ 30 dni
callLog
Kateri od obeh telefonov je klical, kdaj, glasovni ali video klic, sprejet, zamujen ali zavrnjen, in kako dolgo je trajal. Berljivo za naš strežnik — tako telefon, ki je bil izklopljen, izve za zamujen klic. Hranjeno 90 dni, izbrisano, ko prekineta povezavo. Nikoli zvok ali slika
Calls
Voice and video are peer-to-peer WebRTC with DTLS-SRTP and fresh keys for every call. The call setup rides the encrypted relay like any message. Before media flows, your phone checks the peer's DTLS fingerprint against a key derived from the pairing secret; a failed check aborts the call.
Kadar omrežje blokira neposredno pot, rele posreduje pakete, ki jih ne more prebrati. Noben medijski strežnik nikoli ne sliši klica in noben klic ni posnet. Deluje med iPhonom in Androidom. Naš strežnik hrani dnevnik klicev — kateri telefon je klical, kdaj, glasovni ali video klic, izid in koliko je trajal — 90 dni, da partner, čigar telefon je bil izklopljen, vseeno vidi zamujeni klic. Več na /calls.
Safety Mode
Encryption protects her data from outsiders and from us. Safety Mode is for the case where the person on the other end is the concern. She can pause sharing at any time, and he is never notified. She can also turn on Safety Mode, which substitutes neutral data he cannot distinguish from a real update.
When Safety Mode is active, the partner sees:
Phase
“Follicular”
Mood
“Good”
Energy
3 (Moderate)
The neutral data is encrypted and sent through the normal relay, so it looks the same as a real update in transit and on his screen.
Questions
Encrypted between the two phones. We never hold the key.
No phone number, no email, no account. The same cryptography on iPhone and Android, and a relay that forwards ciphertext it cannot open.
