[jose] How would x5u really be used with JWE?

Brian Campbell <bcampbell@pingidentity.com> Tue, 22 January 2013 18:10 UTC

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From: Brian Campbell <bcampbell@pingidentity.com>
Date: Tue, 22 Jan 2013 11:10:28 -0700
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Subject: [jose] How would x5u really be used with JWE?
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Is there a concrete use case for this that someone could explain to me?

How does an encrypting party know what URL to use to get the key to
encrypt? I assume some out-of-band exchange. How would key rolling work
then? An an encrypting party would need to a priori know all potential
x5u's of the decrypting party? Which seems dubious. And how would the
decrypting party signal a desired change of keys?

Am I missing something obvious here?