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 |
| Bedienertoegang tot boodskap- en oproepinhoud | Geen. Ons hou nooit die sleutel nie. |
| What the relay stores | Koppelings-ID, boodskaptipe, tydstempel, grootte, versleutelde teks — uitgevee sodra afgelewer, hoogstens 30 dae |
| Foto's, video's en lêers | Tot 2 GB, verseël met 'n vars sleutel per lêer wat net julle twee foone het; uitgevee sodra afgelaai, hoogstens 30 dae. Aan 'n maat-app wat nog nie opgedateer is nie: tot 25 MB onder die koppelingsleutel, 30 dae bewaar |
| Oproeplogboek | Watter foon gebel het, wanneer, stem of video, die uitkoms en duur — leesbaar vir ons bediener, 90 dae bewaar, uitgevee wanneer julle ontkoppel. Nooit die klank of video nie. |
| 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
Ons bediener is 'n posbus vir verseëlde koeverte. Dit hou versleutelde teks net totdat die ander foon dit afhaal, en vee dit dan uit — hoogstens na 30 dae, as daardie foon vanlyn bly. Dit hou nooit 'n sleutel nie. Push-kennisgewings dra geen teks nie; die foon ontsleutel plaaslik.
PinkyBloom
Encrypts on her phone
Blind Relay
Hou versleutelde teks tot dit afgelewer is, hoogstens 30 dae
Cannot decrypt
PinkyBond
Decrypts on your phone
Alles wat ons bediener oor 'n boodskap, 'n lêer en 'n oproep bewaar:
pairingId
Identifier for the pairing; not a name, number or email
senderRole
Which app sent it: PinkyBloom or PinkyBond
messageType
Watter soort koevert dit is — byvoorbeeld 'n klets-boodskap, 'n status-momentopname, 'n ontvangsbewys of 'n oproep-opstelling — nooit wat binne-in is nie
timestamp
When it was sent
ciphertext
AES-256-GCM blob we cannot open; its length is the only thing we can measure
retention
Uitgevee sodra die ander foon dit ontvang; hoogstens 30 dae as dit vanlyn bly
relayReceipts
Ná aflewering, 'n rekord sonder inhoud: watter boodskap dit was en of dit afgelewer is of verval het. 30 dae bewaar, sodat die sender se foon “nie afgelewer nie” kan wys
mediaObjects
Foto's, stemnotas, video's en lêers tot 2 GB, as versleutelde teks op Cloudflare R2 gestoor, met 'n vars sleutel per lêer wat net binne die versleutelde boodskap saamreis. Uitgevee sodra jou maat se foon dit afgelaai het; hoogstens 30 dae
callLog
Watter van die twee foone gebel het, wanneer, stem of video, beantwoord, gemis of geweier, en hoe lank dit geduur het. Leesbaar vir ons bediener — so leer 'n foon wat af was, nogtans van 'n gemiste oproep. 90 dae bewaar, uitgevee wanneer julle ontkoppel. Nooit klank of video nie
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.
Wanneer 'n netwerk 'n direkte pad blokkeer, stuur 'n relay pakkies aan wat dit nie kan lees nie. Geen mediabediener hoor ooit 'n oproep nie, en geen oproep word opgeneem nie. Dit werk tussen iPhone en Android. Wat ons bediener wél bewaar, is 'n oproeplogboek — watter foon gebel het, wanneer, stem of video, die uitkoms en hoe lank dit geduur het — vir 90 dae, sodat 'n maat wie se foon af was steeds die gemiste oproep sien. Meer by /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.
