Glyff: Privacy-preserving Smart Contracts

Glyff is a decentralized platform combining the blockchain and advanced zero-knowledge cryptography with the goal of delivering privacy-preserving smart contracts and value transfers.
Goal within Glyff project is to deploy decentralized platform that will enable all business to benefit from smart contracts. Of course, design shall foresee that access shall be established without the knowledge of different cryptography codes that are used to obtain high level of security and trust in the system. KYC procedures will be supported within the system, to ensure better compliant and trust in the system. This will provide and enable even the general user with the possibility to develop applications, but without knowledge regarding cryptography. Specialized tool is provided for users, which converts contract written in a high-level domain specific language, that is taken as input, into smart contract in zk-SNARKs, that will prove that the contract is executed correctly, but does not reveal any data regarding contract. Typical contract is divided in public part – that does not interact with financial data, only security deposits and private part – that takes input from participating parties and calculates final pay-out and outcome of the program. These two will be connected into through a system of three smart contracts that are related to cryptographic protocol between users, manager as minimally trusted party and blockchain – blockchain program that is on all consensus nodes, program executed by users and program executed by manager, that is facilitating party in the process.
Glyff represent private cash (shielded value) by a Sapling note, and note is created by a value v, which is spendable by the recipient, that is holding spending key, which is corresponding to a diversified payment address. Single spending key will enable generation of different diversified payment addresses within same spending authority. Full viewing key and incoming viewing key, will be shared by such addresses and users can create as many as unlikable address as they need, without increase in the cost of blockchain scanning for incoming transactions.
Transactions are all transfers that are identified by nodes, and block can be consisted by several transactions. Spend transfers, output transfers, transparent inputs and transparent outputs are defining components of a transactions, and transactions can comprise zero or more of these components.
Above described programmability is in large part adapted from Hawk, with a difference that Glyff uses snarky Ocaml-based domain specific language and front end for compiling private contract programs. Compiler is handles phases of pre-processing, circuit construction and final compiling to all usable executable program for all parties.
GLX standard, that shall enable both private and transparent transactions, combines both ERC20 and ZSL protocol, and users will be able to deploy their own token on the Glyff network, that are fully capable of executing private transactions. GLX API exposes shielding, un-shielding and shielded transfers. All will be visible through Glyff wallet.
Regarding road-map, for the first quarter of 2019 is planned launch for official public test net, beta version of Glyff wallet, with programmable privacy of smart contracts and research interoperability with Ethereum via Plasma.

Project website: https://glyff.io/
Whitepaper: https://glyff.io/files/glyff-wp.pdf
Author: https://bitcointalk.org/index.php?action=profile;u=1573369