# Presentation: 066598

## Security Model Working Group

- TACDFIPSFKMI - WG 2
- April 23, 1997

## Definitions

- Owner - purchaser of a key recovery client system
- Typical owner: corporation or government agency
- Rules for the key recovery client system are set by the owner.
- User - user of the key recovery client system
- Typical user: corporate or government employee
- User follows the rules set by the owner.

## Key recovery agents or data recovery agents

- NSA recommended requirements:  Key recovery agents for law enforcement key recovery, data recovery agents for user or corporate key recovery.
- Suggested modification:  Owners determine acceptable key recovery agents.  This might be the owner as the key recovery agent.

## Interoperability among varying levels of key recovery

- The key recovery product will support an interoperable system between owners of varying security requirements:  Example levels:
- Level 1:  All communications and data must be recoverable through Key Recovery Agents.
- Terminology - Key Recovery Required
- Level 2:  Data must be recoverable through Key Recovery Agents, no requirements on communications.
- Level 3:  No requirements for key recovery.

## Interoperability 

- A Key Recovery Required system should not be able to send or receive any encrypted messages that do not have valid key recovery information attached for that client system.
- A Key Recovery Required system should have the capability to interoperate with systems that do not incorporate key recovery.

## Knowledge of potential recovery

- Each party should be able to determine whether the communication can be recovered.

## No security degradation

- The security mechanisms used in the data recovery mechanisms must be as strong as the underlying security mechanisms.

## Difficulty of disabling key recovery

- NSA recommended requirement 4.1:  The key recovery product shall be resistant to efforts to disable or circumvent the key recovery mechanism.
- Suggested Addition: The difficulty of removing the key recovery features from the products should be as difficult as the difficulty of installing and using secure encryption software that does not incorporate key recovery features.

## Difficulty of disabling key recovery

- NSA recommended requirement 4.1:  The key recovery product shall be resistant to efforts to disable or circumvent the key recovery mechanism.
- Suggested Addition: The difficulty of removing the key recovery features from the products should be more difficult than the difficulty of installing and using secure encryption software that does not incorporate key recovery features.
- Example:  The sender should not be able to remove necessary key recovery information and still have the message read by the receiver.

## Owner access

- NSA recommended requirement 1.13:  The framework shall support corporate key recovery independent of law enforcement access.
- Suggested modification:  There should be a mechanism for a user or owner to be able to recover their own keys, without involving law enforcement.

## More owner options

- An owner could choose to recover the long term or master keys of devices that he owns.  (Not an option for law enforcement.)
- The system should be able to be deployed in systems that provide varying levels of privacy protection.
- An owner can specify how long the key recovery agents can hold the keys.

## Encryption algorithms

- The key recovery mechanism will be independent of the data encryption algorithm.
- The owner can specify some restricted set of algorithms.

## Questions from the working group

- Should the FIPS be able to interoperate with exportable encryption products, where exportable implies legally and commercially exportable?
- How will the inputs from the working groups and the government be incorporated into a single set of requirements?
- What is the decision making procedure for this committee?