Splinter v0.6 Release

Splinter v0.6 is a major new release. Here’s a summary of the new and noteworthy features in this release. For detailed changes related to the v0.6 release see the Splinter release notes.

New and Noteworthy

Challenge Authorization

Splinter now includes an additional authorization method between peers called Challenge Authorization. This authorization method requires the nodes to identify themselves using public-private key pairs.

Nodes prove their ownership of the public key by providing cryptographic signatures using the associated private keys. This new authorization method improves upon trust authorization by providing needed proof of identity.

For more detailed information, see the Challenge Authorization design

Circuit Removal

Splinter now includes additional controls over the life-cycle of a circuit. A circuit can now be disbanded or abandoned, and its data can be purged locally.

Circuit Disband

Disbanding a circuit entails removing a circuit’s networking capabilities. Before a circuit is disbanded, however, all members of the circuit must agree to disband, following a similar procedure to creating a circuit. A node’s administrator may request to disband the circuit, which will create a proposal with the new state of the circuit.

Once the disband request has been validated, the proposal is available to all circuit members. Then all members are either able to accept or reject the proposal. If the proposal is rejected, the proposal is removed and the circuit remains active. If the proposal is accepted, the circuit state for all member nodes is changed to match the content of the proposal and the networking capability of the circuit is switched off.

After the circuit is disbanded, any service state is retained by all member nodes. This state can be purged at a later time (see below).

Circuit Abandon

A node’s administrator may choose to abandon a circuit, removing the circuit’s networking capability from that node’s perspective, without validation from other circuit members. If circuit members attempt to reach the node that abandoned the circuit, via the circuit that was abandoned, the request will fail as that circuit will no longer be able to route the message accordingly. The abandon functionality enables individual circuit members to leave a circuit if they so choose.

After the circuit is abandoned, any service state is retained by all member nodes. This state can be purged at a later time (see below).

Circuit Purge

Circuits that have been disbanded or abandoned can have their state purged from Splinter’s storage. This includes all of the state for the services included in the circuit.

Purging state is local to a node. It does not affect the member nodes of the circuit.


For more detailed information, see the designs for Circuit Disband, Circuit Abandon, and Circuit Purge.

Cloud-Friendly Deployments

Database Support: PostgreSQL and SQLite

Splinter now supports storing all of its persistent state in either a PostgreSQL or SQLite database. This includes all of the state for Splinter: circuit data, user data, and role-based access control to name a few.

It also includes Scabbard state, as well. Both the transaction receipts and merkle state for a Scabbard service may also be saved in either PostgreSQL or SQLite. LMDB may be used as an optional storage mechanism for saving merkle state.

With the pre-compiled splinterd binary, either PostgreSQL or SQLite may be chosen based on runtime configuration.


The logging system has been overhauled to support more options to better support cloud environments. Through the configuration file the logging system is infinitely user configurable. The system supports logging to any combination of stdout, stderr, file, and rolling file targets. Those logs are independently filterable by their level of severity to tailor logging output to only the logs needed in each deployment.

REST API Security

Additional Authentication Methods

Splinter now supports two additional authentication methods: OAuth2 and Cylinder JWT (JSON Web Token).

OAuth2 support allows the Splinter REST API to integrate with existing enterprise solutions, such as Azure, Google and Github, to provide authentication services. The identity returned from an OAuth2 provider can then be used for access control.

Cylinder JWT support allows other daemons and CLI tools to authenticate with the Splinter REST API by using a signing key to create a JWT. Like challenge authorization, the token includes a public key and a signature that can be used to verify the signer. The public key can be used then be used for access control.

Biome authentication is still available, though still not recommended for production deployments.


Splinter also supports two access control method for authorizing a user’s access to the various REST API endpoints.

Each Splinter node may include a list of public keys in a configuration file. Keys added to the allow_keys file will be allowed access to all REST API endpoints. This list is recommended for node administrators only.

Both keys and identities (Biome and OAuth2) may have their access configured through Splinter’s role-based access control system. Access can be granted via roles which, in turn, have a set of permissions associated with them.

All authorization configuration is limited to a single node, and does not affect any other members of a given circuit.

For more information, see the Configuring REST API Authorization guide.

And More

  • Circuit Display Name ability to add a human readable name to the circuit definition
  • Circuit Templates simplifies constructing common circuits
  • Metrics basic metrics collection, including Scabbard information
  • Biome profiles storage for user profiles, including basic information retrieved from an OAuth2 provider


This release includes documentation for Splinter concepts, features, and tasks (under development), API reference guides, CLI man pages, and a comprehensive walkthrough for the Gameroom example application.

Splinter Software

Splinter is open-source software that is available on GitHub in splintercommunity/splinter. Prebuilt Docker images are published on splintercommunity.

For information on building and running Splinter, see the Splinter README.