QED - Scalable, auditable and high-performance tamper-evident log

QED is an open-source software that allows you to establish trust relationships by leveraging verifiable cryptographic proofs.

It can be used in multiple scenarios:

• Data transfers.
• System (or application or business) logging.
• Distributed business transactions.
• Etc.

QED guarantees that the system itself, even when deployed into a non-trusted server, cannot be modified without being detected. It also provides verifiable cryptographic proofs in logarithmic relation (time and size) to the number of entries.

QED is scalable, resilient and ops friendly:

• Designed to manage billions of events per shard
• Over 2000 operations per second per shard under sustained load
• Consistent replication through RAFT
• Operable and instrumented with dozens of metrics
• Zero config files, fully documented single binary

Documentation

You can find the complete documentation at: Documentation

Project code

You can find the project code at Github

Authors

QED was made by Hyperscale BBVA-Labs Team.

License

QED is Open Source and available under the Apache 2 license.

Contributions

Contributions are very welcome. See docs/source/contributing/contributing.rst or skim existing tickets to see where you could help out.

Contents

The Project

• Overview
  • What’s QED
  • Why
  • How
• Quick start
  • 1. Environment set up
  • 2. Adding events.
  • 3. Proof of event insertion.
  • 4. Incremental proof between 2 events.
• Trust Model
  • Description
  • Simple scenario
• Frequently Asked Questions
  • 1. Why would anyone want to verify other’s activities?
  • 2. What is considered a user in QED?
  • 3. Can QED ensure an event is legit?
  • 4. But how can QED help me to achieve that guarantees?
  • 5. How is QED different from digital signatures or blockchain?
  • 6. Is it secure?
  • 7. Will QED alert me from changes or tampering attempts?
  • 8. Is QED a data store? Can I save my data into QED to secure it?

Use Cases

• Commit certification
  • Theory and operation
  • Working example
• Certification of Documents, Emails, Agreements, etc.
  • Theory and Operation
  • Working example
• Lie Detector for Tweeter feeds
  • Theory and Operation
  • Working example

Internals

• Architecture and components
• How does it works (long version)
• Security Model
• Glossary
  • Cryptographic primitives
  • Digital signatures
  • Tree-based data structures
  • Merkle tree
  • History tree
  • Binary search tree
  • Heap
  • Treap
  • Hash treap
  • Sparse Merkle tree

Advanced usage

• Cluster mode
  • 1. Environment set up
  • 2. Checking cluster information.
  • 3. Adding events.
  • 4. Querying membership proof.
  • 5. Shutting down a server
  • 6. Repeat steps 2-4 several times.
• Backup and Restore
  • Backup
  • Restore

Contributing

• Contributing
• Pull requests

References

• Github related projects
• Related papers

Indices and tables

• Index
• Module Index
• Search Page