Bitcoin and Blockchain Technologies Workshop, The University of Stirling, 2016

1. BRIEF
• ``To design and build a distributed ledger POC system
to process and store proprietary messages for inter-
subsidiary forex transactions internal to a major Fortune
500 financial institution’’
• Why? Intermediate message processors add time and
money. Cynically: get in bed with the technology that
may one day supplant them.
• Requirements? Throughput and decentralisation.
www.kwori.co.uk www.kingsoftheblock.com

2. TECHNOLOGY
• Conflicting metrics: transaction throughput vs.
decentralisation
• ≈ BigChainDB vs. ErisDB (Permissioned chains
based on Ethereum / EVM) + Tendermint (PoS;
faster)
• ErisDB brings smart contract technology in the form
of Solidity.
• Both would be employed along with Meteor (novel
client-server communication) and other popular
frameworks such as NodeJS.
• Client selected ErisDB.

3. PROBLEMS
• End product? 4 weeks + N system revisions + 1 proprietary load
balancer = 20 Tx/s. Still several known issues based on Eris bugs.
• Solidity/EVM memory provisioning
• EVM stack depth limits function implementation.
• Solidity/EVM memory management
• Memory provisioning not sufficient for basic data structure operations
(e.g. adding items to an array).
• Poor documentation and error messages exacerbate everything
• Result = no smart contracts
• Instead, multiple blockchains, application-based filtering and direct
transactions.
• Question the role of smart contracts overall in data processing
applications (i.e. processing on the blockchain), at this stage.