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 |
| Serverens tilgang til melding- og samtaleinnhold | Ingen. Vi har aldri nøkkelen. |
| What the relay stores | Koblings-ID, meldingstype, tidsstempel, størrelse, kryptert tekst — slettet så snart den er levert, høyst 30 dager |
| Bilder, videoer og filer | Opptil 2 GB, forseglet med en ny nøkkel per fil som bare de to telefonene deres har; slettet så snart den er lastet ned, høyst 30 dager. Til en partner-app som ikke er oppdatert ennå: opptil 25 MB under koblingsnøkkelen, oppbevart i 30 dager |
| Samtalelogg | Hvilken telefon som ringte, når, tale eller video, utfallet og varigheten — leselig for serveren vår, oppbevart i 90 dager, slettet når dere kobler fra hverandre. Aldri lyden eller bildet. |
| 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
Serveren vår er en postkasse for forseglede konvolutter. Den holder på kryptert tekst bare til den andre telefonen henter den, og sletter den så — høyst etter 30 dager, hvis den telefonen forblir offline. Den har aldri en nøkkel. Push-varsler inneholder ingen tekst; telefonen dekrypterer lokalt.
PinkyBloom
Encrypts on her phone
Blind Relay
Holder på kryptert tekst til den er levert, høyst 30 dager
Cannot decrypt
PinkyBond
Decrypts on your phone
Alt serveren vår lagrer om en melding, en fil og en samtale:
pairingId
Identifier for the pairing; not a name, number or email
senderRole
Which app sent it: PinkyBloom or PinkyBond
messageType
Hva slags konvolutt det er — for eksempel en chat-melding, et status-øyeblikksbilde, en kvittering eller et samtaleoppsett — aldri hva som er inni
timestamp
When it was sent
ciphertext
AES-256-GCM blob we cannot open; its length is the only thing we can measure
retention
Slettet så snart den andre telefonen mottar den; høyst 30 dager hvis den forblir offline
relayReceipts
Etter levering, en oppføring uten innhold: hvilken melding det var, og om den ble levert eller utløp. Oppbevart i 30 dager, slik at avsenderens telefon kan vise «ikke levert»
mediaObjects
Bilder, talenotater, videoer og filer opptil 2 GB, lagret på Cloudflare R2 som kryptert tekst under en ny nøkkel per fil som bare reiser inne i den krypterte meldingen. Slettet så snart partnerens telefon har lastet den ned; høyst 30 dager
callLog
Hvilken av de to telefonene som ringte, når, tale eller video, besvart, tapt eller avvist, og hvor lenge den varte. Leselig for serveren vår — det er slik en telefon som var av, likevel får vite om en tapt samtale. Oppbevart i 90 dager, slettet når dere kobler fra hverandre. Aldri lyd eller bilde
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.
Når et nettverk blokkerer en direkte vei, videresender et relé pakker det ikke kan lese. Ingen medieserver hører noensinne en samtale, og ingen samtale blir tatt opp. Det fungerer mellom iPhone og Android. Det serveren vår beholder, er en samtalelogg — hvilken telefon som ringte, når, tale eller video, utfallet og hvor lenge den varte — i 90 dager, slik at en partner hvis telefon var av, likevel ser den tapte samtalen. Mer på /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.
