Comments below...
What exactly is this key for? I believe it is for round trip verification ...
does resetting it have any impact on forward secrecy?
On Wednesday 24 October 2007 15:15, you wrote:
> Author: nextgens
> Date: 2007-10-24 14:15:17 +0000 (Wed, 24 Oct 2007)
> New Revision: 15523
>
> Modified:
> trunk/freenet/src/freenet/node/FNPPacketMangler.java
> Log:
> JFK:
> Change the transient key on a regular basis (at least once every
> 30mins).
We need it to be deterministic if we want to have a strict PFS interval.
>
> Modified: trunk/freenet/src/freenet/node/FNPPacketMangler.java
> ===================================================================
> --- trunk/freenet/src/freenet/node/FNPPacketMangler.java 2007-10-24
> 09:53:20
UTC (rev 15522)
> +++ trunk/freenet/src/freenet/node/FNPPacketMangler.java 2007-10-24
> 14:15:17
UTC (rev 15523)
> - // The following is used in the HMAC calculation of JFK message3 and
message4
> + /** The following is used in the HMAC calculation of JFK message3 and
message4 */
> private static final byte[] JFK_PREFIX_INITIATOR, JFK_PREFIX_RESPONDER;
> static {
> byte[] I = null,R = null;
> @@ -103,6 +100,21 @@
> private static final int TRANSIENT_KEY_SIZE = HASH_LENGTH;
> /** The key used to authenticate the hmac */
> private final byte[] transientKey = new byte[TRANSIENT_KEY_SIZE];
> + public static final int TRANSIENT_KEY_REKEYING_MIN_INTERVAL =
> 30*60*1000;
> + /** The Runnable in charge of rekeying on a regular basis */
> + private final Runnable transitentKeyRekeyer = new Runnable() {
> + public void run() {
> + resetTransientKey();
> +
> + try {
> + // Ugly hack to let the node start up. When we
> are first
> + // called in the constructor the ticker is not
> available!
> + while(!node.isHasStarted())
> + Thread.sleep(1000);
> + } catch (InterruptedException e) {}
> + node.getTicker().queueTimedJob(transitentKeyRekeyer,
TRANSIENT_KEY_REKEYING_MIN_INTERVAL);
> + }
> + };
All you have to do is add a start() method to FNPPacketMangler, and have it
called during the start() phase of the node (before PacketSender start).
Include the initial scheduling of the above in that method.
> /** Minimum headers overhead */
> private static final int HEADERS_LENGTH_MINIMUM =
> 4 + // sequence number
> @@ -139,7 +151,10 @@
> fullHeadersLengthMinimum = HEADERS_LENGTH_MINIMUM +
sock.getHeadersLength();
> fullHeadersLengthOneMessage = HEADERS_LENGTH_ONE_MESSAGE +
sock.getHeadersLength();
> logMINOR = Logger.shouldLog(Logger.MINOR, this);
> - resetTransientKey();
> +
> + // Yeah there is a race condition... the key might be at 0 for
> a while...
> + // but it will get reset soonish and current runs will be
> invalidated.
> + node.executor.execute(transitentKeyRekeyer, "JFK
> transientRekeyer");
> }
Should be in start(), *not* in FNPPM.
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