The Shape of Code

My previous post on Ethereum contracts got me thinking about how Ethereum should be going about creating a language and virtual machine for the contracts aspect of their cryptocurrency.

I would base the contract development gui on Scratch. Contract development will involve business people and having been extensively field tested on children Scratch stands some chance of being usable for business types.

For the language itself I would find a language already being used for contract related programming and simply adopt it.

At the moment the internal specification of contracts is visible for all to see. I expect a lot of people will be unwilling to share contract information with anybody outside of those they are dealing with. The Ethereum Virtual Machine needs to include opcodes that perform Homomorphic encryption, i.e., operations on encrypted values producing a result that is the encrypted version of the result from performing the same operation on the unencrypted values. Homomorphic encryption operations would allow writers of contracts that keep sensitive numeric values secret, they get to decide who gets a copy of thee dencryption keys needed to see the plain-text result.

The only way I see of overcoming the denial-of-service attack outlined in my previous post is to require that the miner who receives payment for executing a contract prove that they did the work of executing the contract by including program values existing at various randomly chosen points of contract execution.