Open Protocol

The Protocol
for Digital Commitments

PrometheanLink is an open standard for creating cryptographically signed, verifiable commitments between any two parties. No blockchain required.

Read the Spec View on GitHub

The Vision

A world where every digital commitment is mathematically verifiable, tamper-proof, and independent of any central authority.

🔐

Cryptographic Truth

Every commitment is signed with Ed25519 keys. The signature IS the proof. No trust required, no authority needed, no faith in institutions.

🌐

Federated by Design

Instances connect peer-to-peer. No central server. No single point of failure. Your data stays on your infrastructure.

📜

Open Standard

Anyone can implement the protocol. Interoperability is guaranteed. The specification is public and will remain so.

Lightweight

No blockchain overhead. No consensus mechanisms. No mining. Just signatures and hashes. Fast, efficient, practical.

🔗

Chain Integrity

Each packet references the previous. Tampering breaks the chain. History is immutable and auditable.

🤝

Mutual Agreement

Dual signatures required. Both parties sign the same hash at the same moment. Neither can forge or deny.

Protocol Overview

A simple flow: Create, Sign, Send, Verify. That's it.

Sender

Creates packet
Signs with private key

Packet

Payload + Hash
+ Signature + Chain

Receiver

Verifies signature
Checks chain integrity

Packet Structure

Every PrometheanLink packet contains the same core fields, ensuring interoperability across all implementations.

  • Protocol Identifier
    Always "promethean-link" + version
  • Packet ID
    Unique identifier (UUID or custom)
  • Packet Type
    MESSAGE, COMMITMENT, HANDSHAKE, etc.
  • Payload
    The actual content (any JSON structure)
  • Payload Hash
    SHA-256 of canonical payload
  • Previous Hash
    Links to prior packet (chain integrity)
  • Signature
    Ed25519 signature of payload hash
packet.json
{
  "protocol": "promethean-link",
  "version": "0.1.0",
  "packet_id": "pkt-7f3a9b2c-001",
  "packet_type": "COMMITMENT",
  "timestamp": "2026-01-25T12:00:00Z",
  "sender_instance": "https://a.example.com",
  "recipient_instance": "https://b.example.com",
  "payload": {
    "type": "service_agreement",
    "terms": "...",
    "value": 50000,
    "currency": "USD"
  },
  "payload_hash": "a7f3b2c1...",
  "prev_hash": "9d8e7f6a...",
  "signature": "Ed25519(...)"
}

Technical Specifications

The cryptographic primitives that make it work.

Signature Algorithm

Ed25519

EdDSA over Curve25519

Hash Function

SHA-256

For payload and chain hashing

Key Size

256-bit

32-byte public keys

Signature Size

64 bytes

Compact and efficient

Encoding

Base64

For keys and signatures

Transport

HTTPS

TLS 1.3 recommended

Use Cases

PrometheanLink works anywhere commitments need to be verifiable.

📝

Contracts & Agreements

Sign service agreements, NDAs, or any legal document. Both parties sign the same hash. Proof of agreement forever.

packet_type: "DUAL_SIGNATURE_AGREEMENT"
💬

Verified Messaging

Cross-organization chat where every message is signed. Know exactly who said what, with cryptographic proof.

packet_type: "FEDERATED_MESSAGE"
📦

Supply Chain

Track goods across organizations. Each handoff is signed. Verify the entire chain of custody.

packet_type: "CUSTODY_TRANSFER"
🏦

Financial Commitments

Record payment promises, invoices, or transfers. Immutable audit trail for every transaction.

packet_type: "PAYMENT_COMMITMENT"
🎓

Credentials & Certificates

Issue verifiable credentials. Diplomas, certifications, licenses. Anyone can verify without calling the issuer.

packet_type: "VERIFIABLE_CREDENTIAL"
🗳️

Governance & Voting

Board resolutions, shareholder votes, DAO governance. Every vote is signed and auditable.

packet_type: "SIGNED_VOTE"

Why PrometheanLink?

How it compares to other approaches.

Feature
PrometheanLink
Blockchain
Traditional
Cryptographic Proof
Yes
Yes
No
No Central Authority
Yes
Yes
No
Instant Finality
Yes
No
Yes
No Transaction Fees
Yes
No
Yes
Self-Hosted
Yes
Partial
Partial
Energy Efficient
Yes
No*
Yes
Private by Default
Yes
No
Depends

Standard Endpoints

Every PrometheanLink-compliant instance exposes these endpoints.

endpoints.txt
# Discovery
GET  /.well-known/promethean-link.json
     Returns instance identity and public key

# Federation
POST /api/federation/handshake
     Exchange keys with another instance

# Messaging
POST /api/federation/receive
     Receive signed packets from federated instances

# Verification
GET  /api/verify/{packet_id}
     Verify a packet's signature and chain

Start Building

PrometheanLink is open source. Implement it in your application, or try SMARTiDATA for a complete solution.