I was also about to mention SSI. The Decentralized Identifiers (DIDs) [1], and Verifiable Credentials [2] are W3C Recommendations for solving this exact problem

I was also about to mention SSI. The Decentralized Identifiers (DIDs) [1], and Verifiable Credentials [2] are W3C Recommendations for solving this exact problem. There are implementations of these also - check Hyperledger Indy and the Identity Foundation projects [3]. I along with IBM Research folks wrote a paper on even more interesting ways of exchanging identity information between two entities called Private Certifier Intersection [4]. [1] https://www.w3.org/TR/did-core/ https://www.w3.org/TR/did-core/ [2] https://www.w3.org/TR/vc-data-model/ https://www.w3.org/TR/vc-data-model/ [3] https://identity.foundation/ https://identity.foundation/ [4] https://www.ndss-symposium.org/ndss-paper/private-certifier-intersection/ https://www.ndss-symposium.org/ndss-paper/private-certifier-...