corda/docs/source/release-notes.rst

Release notes

Here are release notes for each snapshot release from M9 onwards.

Unreleased

The transaction finalisation flow (FinalityFlow) has had hooks for alternative implementations, for example in scenarios where no single participant in a transaction is aware of the well known identities of all parties.

Milestone 13

Following our first public beta in M12, this release continues the work on API stability and user friendliness. Apart from bug fixes and code refactoring, there are also significant improvements in the Vault Query and the Identity Service (for more detailed information about what has changed, see changelog). More specifically:

The long awaited new Vault Query service makes its debut in this release and provides advanced vault query capabilities using criteria specifications (see QueryCriteria), sorting, and pagination. Criteria specifications enable selective filtering with and/or composition using multiple operator primitives on standard attributes stored in Corda internal vault tables (eg. vault_states, vault_fungible_states, vault_linear_states), and also on custom contract state schemas defined by CorDapp developers when modelling new contract types. Custom queries are specifiable using a simple but sophisticated builder DSL (see QueryCriteriaUtils). The new Vault Query service is usable by flows and by RPC clients alike via two simple API functions: queryBy() and trackBy(). The former provides point-in-time snapshot queries whilst the later supplements the snapshot with dynamic streaming of updates. See api-vault-query for full details.

We have written a comprehensive Hello, World! tutorial, showing developers how to build a CorDapp from start to finish. The tutorial shows how the core elements of a CorDapp - states, contracts and flows - fit together to allow your node to handle new business processes. It also explains how you can use our contract and flow testing frameworks to massively reduce CorDapp development time.

Certificate checks have been enabled for much of the identity service. These are part of the confidential (anonymous) identities work, and ensure that parties are actually who they claim to be by checking their certificate path back to the network trust root (certificate authority).

To deal with anonymized keys, we've also implemented a deterministic key derivation function that combines logic from the HMAC-based Extract-and-Expand Key Derivation Function (HKDF) protocol and the BIP32 hardened parent-private-key -> child-private-key scheme. This function currently supports the following algorithms: ECDSA secp256K1, ECDSA secpR1 (NIST P-256) and EdDSA ed25519. We are now very close to fully supporting anonymous identities so as to increase privacy even against validating notaries.

We have further tightened the set of objects which Corda will attempt to serialise from the stack during flow checkpointing. As flows are arbitrary code in which it is convenient to do many things, we ended up pulling in a lot of objects that didn't make sense to put in a checkpoint, such as Thread and Connection. To minimize serialization cost and increase security by not allowing certain classes to be serialized, we now support class blacklisting that will return an IllegalStateException if such a class is encountered during a checkpoint. Blacklisting supports superclass and superinterface inheritance and always precedes @CordaSerializable annotation checking.

We've also started working on improving user experience when searching, by adding a new RPC to support fuzzy matching of X.500 names.

Milestone 12 - First Public Beta

One of our busiest releases, lots of changes that take us closer to API stability (for more detailed information about what has changed, see changelog). In this release we focused mainly on making developers' lives easier. Taking into account feedback from numerous training courses and meet-ups, we decided to add CollectSignaturesFlow which factors out a lot of code which CorDapp developers needed to write to get their transactions signed. The improvement is up to 150 fewer lines of code in each flow! To have your transaction signed by different parties, you need only now call a subflow which collects the parties' signatures for you.

Additionally we introduced classpath scanning to wire-up flows automatically. Writing CorDapps has been made simpler by removing boiler-plate code that was previously required when registering flows. Writing services such as oracles has also been simplified.

We made substantial RPC performance improvements (please note that this is separate to node performance, we are focusing on that area in future milestones):

• 15-30k requests per second for a single client/server RPC connection.
  • 1Kb requests, 1Kb responses, server and client on same machine, parallelism 8, measured on a Dell XPS 17(i7-6700HQ, 16Gb RAM)
• The framework is now multithreaded on both client and server side.
• All remaining bottlenecks are in the messaging layer.

Security of the key management service has been improved by removing support for extracting private keys, in order that it can support use of a hardware security module (HSM) for key storage. Instead it exposes functionality for signing data (typically transactions). The service now also supports multiple signature schemes (not just EdDSA).

We've added the beginnings of flow versioning. Nodes now reject flow requests if the initiating side is not using the same flow version. In a future milestone release will add the ability to support backwards compatibility.

As with the previous few releases we have continued work extending identity support. There are major changes to the Party class as part of confidential identities, and how parties and keys are stored in transaction state objects. See changelog for full details.

Added new Byzantine fault tolerant (BFT) decentralised notary demo, based on the BFT-SMaRT protocol For how to run the demo see: notary-demo

We continued to work on tools that enable diagnostics on the node. The newest addition to Corda Shell is flow watch command which lets the administrator see all flows currently running with result or error information as well as who is the flow initiator. Here is the view from DemoBench:

We also started work on the strategic wire format (not integrated).

Milestone 11

Special thank you to Gary Rowe for his contribution to Corda's Contracts DSL in M11.

Work has continued on confidential identities, introducing code to enable the Java standard libraries to work with composite key signatures. This will form the underlying basis of future work to standardise the public key and signature formats to enable interoperability with other systems, as well as enabling the use of composite signatures on X.509 certificates to prove association between transaction keys and identity keys.

The identity work will require changes to existing code and configurations, to replace party names with full X.500 distinguished names (see RFC 1779 for details on the construction of distinguished names). Currently this is not enforced, however it will be in a later milestone.

• "myLegalName" in node configurations will need to be replaced, for example "Bank A" is replaced with "CN=Bank A,O=Bank A,L=London,C=GB". Obviously organisation, location and country ("O", "L" and "C" respectively) must be given values which are appropriate to the node, do not just use these example values.
• "networkMap" in node configurations must be updated to match any change to the legal name of the network map.
• If you are using mock parties for testing, try to standardise on the DUMMY_NOTARY, DUMMY_BANK_A, etc. provided in order to ensure consistency.

We anticipate enforcing the use of distinguished names in node configurations from M12, and across the network from M13.

We have increased the maximum message size that we can send to Corda over RPC from 100 KB to 10 MB.

The Corda node now disables any use of ObjectInputStream to prevent Java deserialisation within flows. This is a security fix, and prevents the node from deserialising arbitrary objects.

We've introduced the concept of platform version which is a single integer value which increments by 1 if a release changes any of the public APIs of the entire Corda platform. This includes the node's public APIs, the messaging protocol, serialisation, etc. The node exposes the platform version it's on and we envision CorDapps will use this to be able to run on older versions of the platform to the one they were compiled against. Platform version borrows heavily from Android's API Level.

We have revamped the DemoBench user interface. DemoBench will now also be installed as "Corda DemoBench" for both Windows and MacOSX. The original version was installed as just "DemoBench", and so will not be overwritten automatically by the new version.

Milestone 10

Special thank you to Qian Hong, Marek Skocovsky, Karel Hajek, and Jonny Chiu for their contributions to Corda in M10.

A new interactive Corda Shell has been added to the node. The shell lets developers and node administrators easily command the node by running flows, RPCs and SQL queries. It also provides a variety of commands to monitor the node. The Corda Shell is based on the popular CRaSH project and new commands can be easily added to the node by simply dropping Groovy or Java files into the node's shell-commands directory. We have many enhancements planned over time including SSH access, more commands and better tab completion.

The new "DemoBench" makes it easy to configure and launch local Corda nodes. It is a standalone desktop app that can be bundled with its own JRE and packaged as either EXE (Windows), DMG (MacOS) or RPM (Linux-based). It has the following features:

1. New nodes can be added at the click of a button. Clicking "Add node" creates a new tab that lets you edit the most important configuration properties of the node before launch, such as its legal name and which CorDapps will be loaded.
2. Each tab contains a terminal emulator, attached to the pseudoterminal of the node. This lets you see console output.
3. You can launch an Corda Explorer instance for each node at the click of a button. Credentials are handed to the Corda Explorer so it starts out logged in already.
4. Some basic statistics are shown about each node, informed via the RPC connection.
5. Another button launches a database viewer in the system browser.
6. The configurations of all running nodes can be saved into a single .profile file that can be reloaded later.

Soft Locking is a new feature implemented in the vault to prevent a node constructing transactions that attempt to use the same input(s) simultaneously. Such transactions would result in naturally wasted effort when the notary rejects them as double spend attempts. Soft locks are automatically applied to coin selection (eg. cash spending) to ensure that no two transactions attempt to spend the same fungible states.

The basic Amount API has been upgraded to have support for advanced financial use cases and to better integrate with currency reference data.

We have added optional out-of-process transaction verification. Any number of external verifier processes may be attached to the node which can handle loadbalanced verification requests.

We have also delivered the long waited Kotlin 1.1 upgrade in M10! The new features in Kotlin allow us to write even more clean and easy to manage code, which greatly increases our productivity.

This release contains a large number of improvements, new features, library upgrades and bug fixes. For a full list of changes please see changelog.

Milestone 9

This release focuses on improvements to resiliency of the core infrastructure, with highlights including a Byzantine fault tolerant (BFT) decentralised notary, based on the BFT-SMaRT protocol and isolating the web server from the Corda node.

With thanks to open source contributor Thomas Schroeter for providing the BFT notary prototype, Corda can now resist malicious attacks by members of a distributed notary service. If your notary service cluster has seven members, two can become hacked or malicious simultaneously and the system continues unaffected! This work is still in development stage, and more features are coming in the next snapshot!

The web server has been split out of the Corda node as part of our ongoing hardening of the node. We now provide a Jetty servlet container pre-configured to contact a Corda node as a backend service out of the box, which means individual webapps can have their REST APIs configured for the specific security environment of that app without affecting the others, and without exposing the sensitive core of the node to malicious Javascript.

We have launched a global training programme, with two days of classes from the R3 team being hosted in London, New York and Singapore. R3 members get 5 free places and seats are going fast, so sign up today.

We've started on support for confidential identities, based on the key randomisation techniques pioneered by the Bitcoin and Ethereum communities. Identities may be either anonymous when a transaction is a part of a chain of custody, or fully legally verified when a transaction is with a counterparty. Type safety is used to ensure the verification level of a party is always clear and avoid mistakes. Future work will add support for generating new identity keys and providing a certificate path to show ownership by the well known identity.

There are even more privacy improvements when a non-validating notary is used; the Merkle tree algorithm is used to hide parts of the transaction that a non-validating notary doesn't need to see, whilst still allowing the decentralised notary service to sign the entire transaction.

The serialisation API has been simplified and improved. Developers now only need to tag types that will be placed in smart contracts or sent between parties with a single annotation... and sometimes even that isn't necessary!

Better permissioning in the cash CorDapp, to allow node users to be granted different permissions depending on whether they manage the issuance, movement or ledger exit of cash tokens.

We've continued to improve error handling in flows, with information about errors being fed through to observing RPC clients.

There have also been dozens of bug fixes, performance improvements and usability tweaks. Upgrading is definitely worthwhile and will only take a few minutes for most apps.

For a full list of changes please see changelog.