Libri

Libri is a decentralized data storage network based on the Kademila protocol and approach. It also offers

• end-to-end encryption
• notifications across the network for every storage event

Status

Libri is currently in alpha with a public testnet.

Try it out

Ensure you have Docker installed and then run

./libri/acceptance/local-demo.sh

to spin up a 4-node libri cluster, run some tests against it, and uploaded/download some sample data.

To try out (or join!) our public test network see public testnet doc.

Design

Peers The peers of the network are called librarians. Each librarian exposes a set of simple endpoints, descripted in librarian.proto for getting and putting documents, described in documents.proto.

Clients The clients of the network are called authors. Each other connects to one or more librarian peers to upload/download documents and receive publications when others upload documents they are interested in.

This simple architecture looks something like

                       ┌───────────┐
                       │┌──────────┴┐
                       └┤ librarian │
                        └───────────┘
                              ▲
                              │
           ┌───────────┐      │    ┌───────────┐
           │┌──────────┴┐     │    │┌──────────┴┐
           └┤ librarian │◀────┴────▶┤ librarian │
            └───────────┘           └───────────┘
                  ▲                       ▲
                  │                       │        public libri network
─ ─ ─ ─ ─ ─ ─ ─ ─ ┼ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ┼ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─
            ┌─────┴────┐                  │             private clients
            │          │                  │
            ▼          ▼                  ▼
       ┌────────┐ ┌────────┐         ┌────────┐
       │ author │ │ author │         │ author │
       └────────┘ └────────┘         └────────┘

Currently, we have only a Golang author implementation, but we expect to develop other implementations (e.g., Javascript) soon.

Storage Each librarian and author uses RocksDB for local storage.

Identity Author identity is managed through asymmetric ECDH keys. When an author is initialized it generates a cache of ECDH keys. These are always unique for each client, and the private key always stays on the local machine.

Encryption When uploading a document, the author

1. generates a new set of entry encryption keys,
2. uses it to encrypt the data contents into an Entry and publishes that to the Libri network,
3. selects two of its own keys ECDH keys and uses their ECDH shared secret to generate a key encryption key,
4. uses this key encryption key to encrypt the entry encryption key
5. uploads an Envelope containing the two public keys and the entry encryption key ciphertext

When an author wants to share a document with another author, it just repeats steps 3-5 but with a public key of the author to send the document to. Only the Envelope is different (rather than re-encrypting the entire Entry).

Replication Documents are uploaded with a specified number of replicas. If peers storing those replicas drop out of the network, the other peers storing the remaining replicas take charge of storing additional copies to bring the replication factor up to a given level.

Containers

Libri relies heavily on Docker containers, both for development and deployment. The development image (daedalus2718/libri-build) is fairly large (~1.5GB) because it contains all the binary dependencies needed for testing and development. The deployment image (daedalus2718/libri) is fairly small (~90MB) because it contains only the things needed to run the libri command line binary.

Contribute

See CONTRIBUTING.md for details. Issues, suggestions, and pull requests always welcome.

Get in touch via contact AT libri.io.

References

• Kademila protocol and approach
• libri is inspired by similar p2p distributed storage efforts Ethereum Swarm and Storj, among others
  • these two efforts also use variants of the Kademlia protocol
  • unlike these two, libri will not include any blockchain or contracts