Despite their hype, enterprise blockchains currently suffer from a lack of scalability and governance, among other things. This contribution introduces regulators and satellite chains, respectively, to overcome these two limitations.

The basic idea behind regulators is the concept that every transaction in the blockchain shall be further tested against a set of central policies, which are stored in the form of policy chaincodes (Hyperledger speak for smart contracts) and are collectively enforced by a master policy directory chaincode. Regulators are nodes in a blockchain that “ensure that all transactions in the network are validated and comply with ... policy.”

Besides introducing fairly trivial properties of satellite chains (that is, a situation where a node participates in several different blockchains at the same time), the paper expands the (highly interesting) use case of cross-chain asset transfer. Using simple but otherwise unspecified pseudocode, the authors offer an algorithm where the validation nodes of two different blockchains might move assets (for example, coins or tokens) from one blockchain to the other.

Both concepts sound fine and correct at the conceptual level, but, deplorably, the authors fail to address the real problems of using them, even though they claim to have implemented everything in Hyperledger Fabric 0.6.

Regarding regulators, for instance, how would you really ensure that every chaincode eventually calls another policy chaincode for checking? Is that something built into the virtual machine of the validating nodes? Provided explanations and a nonstandard architecture diagram fall considerably short of that task.

Regarding cross-chain asset transfers, not all nontrivial parts of an implementation are described, for example, how the two chains involved in the transaction deal with the probabilistic finality of each chain, how to deal with time outs, and so on. Pseudocode and explanations remain at a very superficial level, but it remains unclear how the real implementation deals with this type of situation. Contrary to the authors’ claim, the algorithm only works for identical satellite chains because no algorithm for the then-required asset conversion is foreseen.

Notwithstanding the criticism of its details, the paper is easy to access and recommended for any solution architect in the blockchain domain who has not yet stumbled upon satellite chains, cross-chain asset transfer, or chaincode/smart contract governance mechanisms.