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Below diagram shows the steps required to use the delegation tokens.

Q/A

Q1. Is there any dependency on Hadoop APIs/Libraries?

A. No.

Future Work

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1.  Support for master key rotation
2.  Support impersonation Use use cases: Allow users to acquire delegation tokens on behalf of other users

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• Let each broker generate a Random secret on each acquisition request and use this secret to generate the hmac. Broker will store the hmac and secret in zookeeper. However as zkClient does not support SSL the hmac will be on wire unencrypted which is not safe.
• Use controller instead of zookeeper as the central location where tokens are generated,renewed and distributed from. You can review the discussion and pro/con here.
• Use the controller to generate and rotate secret and distribute it to all brokers. Brokers will generate hmac based on *current* secret. The advantage is secret rotation can be more frequent and automated. The disadvantage is added complexity to push/pull tokens from the controller to brokers and brokers needs to keep a list of valid secrets till max( max life time of all tokens).

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