Ping-Pong Wake Protocol
ShadowTalk's stateless, serverless delivery handshake that ensures messages are only delivered when you are physically present and have unlocked your device.
1. Purpose
The Ping-Pong Wake Protocol is ShadowTalk's stateless, serverless delivery handshake.
It solves one brutal requirement:
"Do not deliver a message to my device unless I am physically present and have unlocked it."
This guarantees:
- •No centralized queue.
- •No metadata about communication partners.
- •No auto-delivery to seized/compromised devices.
Ping-Pong is the high-security mode of ShadowTalk. Other users can still use the asynchronous encrypted relay mode for convenience.
2. Roles
- •Sender (S): Creates and encrypts the message.
- •Receiver (R): Authenticates and retrieves the message.
No permanent servers or relays are required. Relays can act only as optional transport layers for wake tokens, never as message custodians.
3. Cryptographic Material
Each ShadowTalk identity includes:
- •Identity Key (Ed25519): Long-term signing key for authenticity.
- •Wake Key (Ed25519/X25519): Used for ping/pong wake encryption.
- •Session/Chat Keys: Ephemeral keys for message encryption (Double Ratchet-style).
- •Queue Encryption Key: Protects locally queued messages.
All private keys are stored in hardware security modules (StrongBox / Secure Enclave).
4. Lifecycle Overview
- 1.Sender creates message M.
- 2.M is encrypted → ciphertext C.
- 3.C queued locally in sender device's encrypted queue.
- 4.Sender generates Ping token P (encrypted + signed).
- 5.P transmitted via socket, alarm, or UnifiedPush to receiver.
- 6.Receiver device wakes. App prompts user authentication.
- 7.After unlock, receiver signs Pong token Q.
- 8.Q sent back to sender.
- 9.Sender verifies Q, establishes session channel.
- 10.Sender transmits C.
- 11.Receiver decrypts and confirms delivery.
- 12.Both devices purge ephemeral data.
5. Security Properties
No Premature Disclosure
Message payload never leaves sender's device until receiver confirms readiness and authentication.
Zero Relay Storage
No permanent relay or third-party storage required for message content.
Replay Protection
Ping/Pong tokens include cryptographic nonces and timestamps.
Forward Secrecy
Each Ping-Pong cycle uses ephemeral session keys.
Metadata Minimization
Ping/Pong tokens are opaque encrypted blobs. No sender/receiver identifiers visible.
Conclusion
The Ping-Pong Wake Protocol represents a genuine breakthrough in serverless, metadata-free messaging. It guarantees that no message can be delivered to an unattended or compromised device, making it the gold standard for high-security communication.