[dtn-security] Key Distribution

Ian Glennon <ianglennon@gmail.com> Tue, 29 November 2011 21:26 UTC

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Date: Tue, 29 Nov 2011 21:26:33 +0000
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From: Ian Glennon <ianglennon@gmail.com>
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Subject: [dtn-security] Key Distribution
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I'm considering the following situation...

Nodes A, B and C are Security Aware DTN Nodes.  Node B is an intermediate
DTN node which handles bundles from Node A to Node C.

1) Node A wishes to encrypt a payload for Node C but does not have a local
copy of the public key for Node C.  Node A will sign the payload using its
private key.  How does Node A obtain the public key?

2) Assuming Node A can obtain Node C's public key, Node B wishes to verify
the integrity of the payload.  How does Node B obtain Node A's public key?

3) On receiving the bundle from Node A, Node C wishes to verify the
integrity of the payload.  How does Node C obtain Node A's public key?

Now clearly the answer to 2) will be the same as that for 3), and also
probably the same for 1).  I am considering some kind of Key Distribution
Node, which would manage the distribution of the public keys to the various
DTN nodes.  At what point, though, would the key request be made?  Would it
be made within the DTN protocol, or would it be made by some application
receiving the bundle payload?  My guess is it would be within the DTN
protocol - certainly for 2) as the verification is handled by the protocol
rather than some application overlaying the protocol.

You may see where I'm going with this - a Key Distribution Network
consisting of nodes handling the distribution of public keys - but I'm not
sure whether requests to a node within the KDNetwork needs to be integrated
into the DTN protocol, or whether it can be an application receiving
requests which sits above the DTN protocol.

Any help, guidance or advice gratefully received.

Ian Glennon