PXxYy

PXxYy is a software protocol and ecosystem designed for interoperable identity verification and secure data exchange across organizational boundaries. It defines a set of protocols and data formats to enable trusted exchange of claims, attributes, and credentials between clients, identity providers, and relying parties.

Development and governance of PXxYy began with the PXxYy Alliance as an open standard project in the early 2020s. The project is community-driven, with input from academia, industry, and government bodies. The protocol has progressed through multiple releases, with early 1.x versions establishing core capabilities and later 2.x releases introducing improvements for scalability, privacy, and interoperability.

Technical overview

PXxYy architecture comprises three principal components: a client library used by applications to request and present credentials; a verifiable credential issuer/holder model; and a verifier service that validates proofs and enforces access decisions. It relies on cryptographic primitives such as digital signatures, zero-knowledge proofs, and identity proofs using decentralized identifiers. The design emphasizes minimal disclosure through selective disclosure and privacy-preserving credentials.

Features and standards

PXxYy interoperates with W3C Verifiable Credentials and Decentralized Identifiers standards, supporting multiple cryptographic suites (including Ed25519 and RSA) and providing pluggable transport and storage back-ends. It supports multi-factor authentication, attribute-based access control, and consent management. The framework is used in federated identity, regulatory compliance workflows, and secure data sharing between organizations.

Security and adoption

The protocol focuses on verifiability, revocation mechanisms, and audit trails, with configurable role-based and policy-based access controls. Adoption ranges from large enterprises to public sector pilots, and open-source reference implementations exist in several programming languages.

Related topics include decentralized identity, verifiable credentials, zero-knowledge proofs, and decentralized identifiers.