Eazy Licensing Tool

This repository provides a minimal offline license signing and verification system using Ed25519 asymmetric cryptography.

The goal is deliberately simple:

• Verify that a license was issued by the holder of the private key
• Detect any modifications to the license data
• Enforce date-based validity

This is not DRM — it is a traditional, lightweight system to keep honest customers honest.

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Design Principles

• Asymmetric signing: private key signs, public key verifies
• Human-readable licenses: no encryption, only signatures
• Deterministic JSON signing: canonical serialization ensures integrity
• Offline verification: no network calls required
• Minimal logic: only signature and date checks

If any field in the license changes, signature verification will fail.

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Intended Usage

• Client collects machine identification and registers / signs up to server
• Client has a license file and verifies signature using the public key (offline)
• Client without a valid license requests one from the server
• Step 4: PROFIT !?!?

Actual client flow

Starting from happy flow

Client

• verifies license validity (offline)
  • loads cached license (from local file?)
  • without local file makes a remote call

Server

• on license request verifies payments and generates a valid license
• on register server creates public / private key pairs for client

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Limitations

• Full control over the runtime allows bypassing verification
• System relies on contracts, payments, and support for enforcement
• No hardware binding or tamper-proofing

This is intentional and aligns with traditional commercial software licensing.