Paper 2020/934

CanDID: Can-Do Decentralized Identity with Legacy Compatibility, Sybil-Resistance, and Accountability

Deepak Maram, Harjasleen Malvai, Fan Zhang, Nerla Jean-Louis, Alexander Frolov, Tyler Kell, Tyrone Lobban, Christine Moy, Ari Juels, and Andrew Miller


We present CanDID, a platform for practical, user-friendly realization of decentralized identity, the idea of empowering end users with management of their own credentials. While decentralized identity promises to give users greater control over their private data, it burdens users with management of private keys, creating a significant risk of key loss. Existing and proposed approaches also presume the spontaneous availability of a credential-issuance ecosystem, creating a bootstrapping problem. They also omit essential functionality, like resistance to Sybil attacks and the ability to detect misbehaving or sanctioned users while preserving user privacy. CanDID addresses these challenges by issuing credentials in a user-friendly way that draws securely and privately on data from existing, unmodified web service providers. Such legacy compatibility similarly enables CanDID users to leverage their existing online accounts for recovery of lost keys. Using a decentralized committee of nodes, CanDID provides strong confidentiality for user's keys, real-world identities, and data, yet prevents users from spawning multiple identities and allows identification (and blacklisting) of sanctioned users. We present the CanDID architecture and its technical innovations and report on experiments demonstrating its practical performance.

Note: Revised version.

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Published elsewhere. 2021 IEEE Symposium on Security and Privacy
decentralized identitydistributed cryptographySybil-resistance
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sm2686 @ cornell edu
2021-05-25: last of 2 revisions
2020-07-29: received
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      author = {Deepak Maram and Harjasleen Malvai and Fan Zhang and Nerla Jean-Louis and Alexander Frolov and Tyler Kell and Tyrone Lobban and Christine Moy and Ari Juels and Andrew Miller},
      title = {{CanDID}: Can-Do  Decentralized Identity with Legacy Compatibility, Sybil-Resistance, and Accountability},
      howpublished = {Cryptology ePrint Archive, Paper 2020/934},
      year = {2020},
      doi = {10.1109/SP40001.2021.00038},
      note = {\url{}},
      url = {}
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