Key Management in AAA

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Key Management in AAA

• Russ Housley
• Incoming Security Area Director

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Introduction

• Some people are concerned that a working group
  outside of the Security Area is designing a key
  management protocols.
• Why?
• Key management protocols are subtle.
• An expert can easily miss a flaw.
• Peer review by multiple experts is essential.

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Concerns with EAP

• Employs new key distribution architecture
• Poorly understood security properties
• Three party models have been well studied, but
  these do not align directly with AAA
• Select one end-to-end mechanism to protect
  distributed keys
• Needs robust key naming scheme
• Needs to establish fresh session keys
• Principle of least privilege not followed

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Acceptable solution MUST

• Be algorithm independent protocol
• For interoperability, select at least one suite
  of algorithms that MUST be implemented
• Establish strong, fresh session keys
• Maintain algorithm independence
• Include replay detection mechanism
• Authenticate all parties
• Maintain confidentiality of authenticator
• NO plaintext passwords

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Acceptable solution MUST also

• Perform client and NAS authorization
• Maintain confidentiality of session keys
• Confirm selection of best ciphersuite
• Uniquely name session keys
• Compromise of a single NAS cannot compromise any
  other part of the system, including session keys
  and long-term keys
• Bind key to appropriate context