Jade Wallet - a MPC-based wallet app

Self-introduction

We primarily focus on providing institutional investors with crypto assets self-custody solution. Jade Wallet uses multi-party computation (MPC) and threshold signature scheme technology to upgrade the crypto assets management to multi-person authorization mode, thus cryptographically eliminating the underlying danger of exposing private keys at any single point.

Jade Wallet has supported Bitcoin and Ethereum (including ERC20 tokens & DApps). With our clients’ enthusiasm for Polkadot&Kusama and the lack of product in market being able to meet their certain needs(including Parity Signer, PolkaWallet and Ledger Nano S/X), we are excited to support both chains and invite them to participate in the ecosystem soon.

Problem statement

There are certain pain points for the institutional investors regarding Polkadot & Kusama:

Multi-person authorization. As a rule, institutional investors need a mechanism to authorize each transaction. They can use the multi-sig smart contract developed by Gnosis Safe to manage assets on Ethereum and use Copay to create a Bitcoin multi-sig account. Although multi-sig accounts are natively supported on Polkadot/Kusama, institutional investors still need a mature and expandable solution with better experience.
Transaction review. For those who pay great attention to security, a mobile phone in airplane mode with Parity Signer installed for signing transactions can be a good choice. However, Parity Signer does not parse the QR code generated by Polkadot/Substrate Portal into readable information. What happens if the QRcode is hacked? How to assume responsibility for loss if there was no chance to review the transaction?
Key management. How to backup the key in multi-person mode? How to prevent private keys or mnemonic phrases from leaking? Are software wallets safe enough? The key management should be decentralized and no one is supposed to know the actual private key

Solutions by Jade Wallet

Multi-person authorization <-> MPC-based threshold signature scheme is based on cryptography and is not limited to specific blockchain. This offers Jade Wallet the ability similar to Multi-signature with better privacy and expandability.
After a wallet member initiates a transaction, a session needs to be created to sign the transaction. To create the signing session, the number of online members should meet the threshold. The experience of signing is just like participating in a ZOOM meeting.
A demo video for using Jade Wallet to transfer eth: https://youtu.be/im4q8hLPpss
Transaction review <-> During the signing session, members must review and confirm the transaction information again before signing. The information is parsed from the raw hash of the built but unsigned transaction, which known as WYSIWYS.

In cryptography, What You See Is What You Sign (WYSIWYS) is a property of digital signature systems that ensures the semantic content of signed messages can not be changed, either by accident or intent. — Wikipedia

Key management <-> Instead of storing private keys or mnemonic phrases, each member only needs to keep his own “Key Share” that is generated by MPC protocol during the wallet creation. We designed a simple and elegant way to backup and restore shares that can be completed in just a few clicks. After the share is successfully generated, a high strength password (EncKey) is randomly generated in the App to encrypt the share. EncKey will be backed up to the member’s own iCloud Drive, while the encrypted copy of the share will be uploaded to the Jade Wallet server and sent to the member via email.

For further details, if you are interested in Jade Wallet, please have a look at our treasury proposal.