A Decentralized Public Key Infrastructure with Identity Retention

Public key infrastructures (PKIs) enable users to look up and verify one another’s public keys based on identities. Current approaches to PKIs are vulnerable because they do not offer sufficiently strong guarantees of identity retention; that is, they do not effectively prevent one user from registering a public key under another’s already-registered identity. In this paper, we leverage the consistency guarantees provided by cryptocurrencies such as Bitcoin and Namecoin to build a PKI that ensures identity retention. Our system, called Certcoin, has no central authority and thus requires the use of secure distributed dictionary data structures to provide efficient support for key lookup.