Nym Credentials: Privacy-Preserving Decentralized Identity with Blockchains

Abstract

Nym credentials solve the problem of privacy-enhanced authentication amongst a decentralized open-ended ecosystem of services. Many blockchain systems offer decentralized services, but at the cost of revealing all transactions in a public ledger, which is clearly not suitable for high-value transactions involving personal data. Nym credentials deploy anonymous authentication credentials as an identity system that maintains user privacy. Due to the validators being decentralized, the system is compatible with blockchain-based systems. Tokens can be used to show the "right to access" privacy-enhanced services. Nym validators transform these tokens into Nym credentials that validated publicly in a decentralized manner via a modified Coconut signature scheme capable of the open-ended embedding arbitrary attributes.