Scalable Secure Identity Establishment

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Scalable Secure Identity Establishment

• Abraham Bachrach, Karl Chen, Rodrigo Fonseca,
  Dilip Joseph, Jeremy Rahe, Ananth Rao
• CS294-8 Fall 2005
• Final presentation _at_ 2005-12-07

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Introduction
Am I really talking to Bank of America? Is it
secure?
Is it really Bob who wants to withdraw 1 million?
Dont PKIs already solve the problem?
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Problems with PKIs

• Too many of them, Not widely trusted
• Entangle authentication authorization
• PKI certifies that Bob has public key PKBob
• PKI also says trust Bob.
• Does not allow pseudonymity
• Verisign has screwed up

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Our Proposal

• Factor out the identity layer
• Maps flat id ? public key
• Identifiers
• 256-bit integer
• Opaque, semantic-free, tussle-free
• First-come, first-serve
• Pseudonymous

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Architecture

• Identity Registrar (like Robot CA)
• Central authority to sign
• flat id ? public key certificates.
• Trusted to execute algorithm (FCFS)
• Publishing System
• Content Distribution Network DHT, etc.
• Not trusted

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How Many Namespaces?

• Alternatives
• Single namespace, single organization
• Single namespace, multiple organizations
• Multiple namespaces
• Thus multiple namespaces
• Each country runs its own registrar
• Ids prefixed with a country code
• Users can register with any I.R.

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Publishing System (e.g., OpenDHT)
Use internal database to lookup Bobs flat id.
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Scalability

• Identity Registrar needs to push keys into the
  Publishing System
• Need to maintain freshness of keys
• Huge bandwidth required
• Delegate freshness to a Certificate Validator

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Publishing System (e.g., OpenDHT)
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Scalability

• Certificate Validator refreshes Validity
  Certificate every N hours
• Trusted only by owner of identifier
• Identity Registrar uninvolved
• Can charge for premium service
• Many will exist

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Applications

• Map from human-readable names to flat identifier
• Traditional trust-establishment mechanisms
• PKI
• PGP-style distributed web of trust
• Chat
• Life, the Universe, and Everything

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Discussion

• Flat ids provide pseudonymity
• Tussle spaces
• DNS, Google, Comcast, Verisign, ICANN, national
  governments
• Users free to trust whoever they want