JPMorgan Adds Privacy Features to Its Quorum Blockchain

The blockchain team at JPMorgan Chase has created a privacy feature for Ethereum-powered blockchains, concealing the amount of money being transferred as well as the sender. 

JPMorgan has developed an extension to the Zether protocol. Zether is a wholly decentralized, cryptographic protocol for confidential payments, designed to add an extra layer of anonymity to transactions and compatible with smart contract and Ethereum platforms. The New York-headquartered firm will open-source the extension on Tuesday and is likely to utilize it with its private version of Ethereum, Quorum.

Developed by a group of financial technology researchers and academics, Zether leverages zero-knowledge proofs (ZKPs) which enables a party to prove knowledge of some confidential information or value without revealing any detail regarding that secret.

“In the basic Zether, the account balances and the transfer accounts are concealed but the participants’ identities are not. So we have solved that. In our implementation, we provide a proof protocol for the anonymous extension in which the sender may hide herself and the transactions recipients in a larger group of parties,” JPM’s head of Quorum and crypto-assets strategy Oli Harris elaborated.

JPMorgan has recently drawn around 220 banks to its Quorum-based Interbank Information Network. It also finished a load of integration work with Microsoft Azure as JPM readies Quorum to become an open-source protocol.

According to Harris, the confidential payments architecture of Zether includes an account-based approach used by Ethereum, as opposed to the UTXO-based approach utilized by Bitcoin client. UTXO is a feature of zcash, which Quorum’s original ZKP component was built on.

In that way, the extension could be beneficial to both Quorum users and enterprises building over other Ethereum variants.

“When we think about the community building on top of Quorum,” Harris stated, “if anyone is looking to get an efficient trustless mechanism for trustless and anonymous payments in a consortium then that’s when it’s relevant. That’s why we wanted to open-source it back to the community so anyone can build on it further and continue enhancing it and potentially put it into their use cases as needed.”

“When we look at our own JPMorgan applications [the extended version of Zether] will be one choice of many that we will be looking at,” Harris added.

The effort to strengthen the confidentiality of transactions on Zether may also be utilized to fine-tune Quorum for deployment within enterprise consortia.

“The performance is quite good; we had done multiple iterations to improve it and we are doing the verification in solidity smart contracts. We’ll be including in our report the performance measurements for proving and verification,” Harris concluded.