Multi-Device

devices The Concept

Use the same Holos account on your phone, tablet, and computer simultaneously. All devices share the same identity, receive the same activities, and stay in sync through the relay.

sync

Your identity keys are securely transferred between devices. Each device becomes a full copy of your account.

qr_code_2 Pairing a New Device

Adding a device is a local, offline-capable process. No data transits through the relay in plaintext.

1

Open Holos on the new device and select "Add to existing account"

2

The new device displays a QR code containing its ephemeral X25519 public key

3

Scan the QR code from your existing device to establish a shared secret (ECDH key agreement)

4

Your existing device encrypts and transfers your identity, keys, followers, and posts over the encrypted channel

info The entire transfer is end-to-end encrypted with AES-256-GCM. Even if intercepted, the data is unreadable without the shared secret derived from the QR code exchange.

enhanced_encryption Key Transfer Security

The QR code pairing uses X25519 Elliptic Curve Diffie-Hellman to establish a shared secret without ever transmitting private keys in the clear.

EXISTING DEVICE

key Holds identity keys

qr_code Scans QR code

swap_vert QR Code (public key)

KEY AGREEMENT

X25519 ECDH
→ shared secret
→ AES-256-GCM

swap_vert Encrypted payload

NEW DEVICE

download Receives encrypted keys

verified Fully operational

inventory_2 What Gets Transferred

During pairing, the following data is securely copied to the new device:

vpn_key

Cryptographic Keys

RSA keypair (ActivityPub signing), Signal Protocol keys (E2EE DMs), and account credentials.

group

Social Graph

Your followers list and following list.

article

Content

Your post history and local database, so the new device starts with full context.

sync Activity Delivery

Once paired, all devices receive activities from the relay independently:

move_to_inbox Incoming Activities

Each device maintains its own sync cursor
Activities are delivered to all connected devices
Entries expire via TTL, not on confirm (multi-device safe)

outbox Outgoing Actions

All outbound actions route through the relay proxy
The relay deduplicates to prevent double-posts across devices

restore Account Recovery

Lost your device? Multiple recovery paths ensure you never lose access:

qr_code_2

QR Transfer

If you still have another paired device, scan a QR code to set up a replacement instantly.

password

Recovery Passphrase

Enter your passphrase on a new device to restore your identity, followers, following, and posts from the encrypted backup on the relay (PBKDF2 + AES-256-GCM, zero-knowledge).

cloud_download

Cloud Backup

Restore your full database from S3-compatible or WebDAV cloud storage, including message history.

code Technology

X25519 ECDH AES-256-GCM PBKDF2 QR Code WebSocket Cursor-based Sync

open_in_new Multi-device implementation is open source. Audit the key transfer protocol or contribute improvements.