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 |
| Access ng server sa content ng mga mensahe at tawag | Wala. Wala kaming hawak na key kailanman. |
| What the relay stores | Pairing id, uri ng mensahe, timestamp, laki, ciphertext — binubura pagkatapos maihatid, pinakamatagal ay 30 araw |
| Mga larawan, video, at files | Hanggang 2 GB, naka-seal gamit ang bagong key kada file na dalawa lang ninyong phone ang may hawak; binubura pagkatapos ma-download, pinakamatagal ay 30 araw. Sa partner app na hindi pa na-update: hanggang 25 MB gamit ang pairing key, itinatago ng 30 araw |
| Call log | Kung aling phone ang tumawag, kailan, voice o video, ang resulta at tagal — nababasa ng server namin, itinatago ng 90 araw, binubura kapag nag-unpair kayo. Hindi kailanman ang audio o video. |
| 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
Ang server namin ay parang mailbox para sa mga naka-seal na sobre. Hinahawakan lang nito ang ciphertext hanggang makuha ito ng kabilang phone, tapos binubura ito — pinakamatagal 30 araw, kung mananatiling offline ang phone na iyon. Hindi ito nagkakaroon ng key kailanman. Walang laman na text ang mga push notification; ang phone ang nag-de-decrypt nang local.
PinkyBloom
Encrypts on her phone
Blind Relay
Hinahawakan ang ciphertext hanggang maihatid, pinakamatagal 30 araw
Cannot decrypt
PinkyBond
Decrypts on your phone
Lahat ng itinatago ng server namin tungkol sa isang mensahe, isang file, at isang tawag:
pairingId
Identifier for the pairing; not a name, number or email
senderRole
Which app sent it: PinkyBloom or PinkyBond
messageType
Kung anong uri ng sobre ito — halimbawa, isang chat message, status snapshot, receipt, o call setup — hindi kailanman kung ano ang laman
timestamp
When it was sent
ciphertext
AES-256-GCM blob we cannot open; its length is the only thing we can measure
retention
Binubura sa sandaling matanggap ito ng kabilang phone; pinakamatagal 30 araw kung mananatili itong offline
relayReceipts
Pagkatapos maihatid, may naiiwan na record na walang content: kung aling mensahe iyon at kung naihatid o nag-expire ito. Itinatago ng 30 araw, para maipakita ng phone ng nagpadala ang “hindi naihatid”
mediaObjects
Mga larawan, voice notes, video, at files na hanggang 2 GB, naka-store sa Cloudflare R2 bilang ciphertext gamit ang bagong key kada file na naglalakbay lang sa loob ng naka-encrypt na mensahe. Binubura pagkatapos ma-download ito ng phone ng partner mo; pinakamatagal 30 araw
callLog
Kung alin sa dalawang phone ang tumawag, kailan, voice o video, sinagot, na-miss, o tinanggihan, at gaano katagal ito. Nababasa ng server namin — ganito nalalaman ng phone na naka-off ang isang na-miss na tawag. Itinatago ng 90 araw, binubura kapag nag-unpair kayo. Hindi kailanman ang audio o video
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.
Kapag hinaharang ng network ang direktang daan, ang relay ay nagpapasa ng mga packet na hindi nito mababasa. Walang media server na nakaririnig kailanman ng tawag, at walang tawag na naitatala. Gumagana ito mula iPhone patungong Android. Ang itinatago ng server namin ay isang call log — kung aling phone ang tumawag, kailan, voice o video, ang resulta, at gaano katagal — sa loob ng 90 araw, para makita pa rin ng partner na naka-off ang phone ang na-miss na tawag. Karagdagang impormasyon sa /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.
