trying to update list of plugins from http://mirrors.karan.org/jenkins/updates/update-center.json

Provides a signing certificate : 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

Once dumped :
Certificate:
Data:
Version: 1 (0x0)
Serial Number: 3735928560 (0xdeadbef0)
Signature Algorithm: md5WithRSAEncryption
Issuer: C=US, ST=California, L=San Jose, O=Jenkins Project, CN=Kohsuke Kawaguchi/emailAddress=kk@kohsuke.org
Validity
Not Before: Apr 19 07:35:04 2011 GMT
Not After : Apr 18 07:35:04 2012 GMT
Subject: C=US, ST=California, O=Jenkins Project, OU=Default Update Center, CN=Kohsuke Kawaguchi

=> certificate expired this morning.

this leads to the following exception when trying to refresh plugins list:

18 avr. 2012 15:28:23 hudson.model.UpdateSite doPostBack
GRAVE: <div class=error><img src='/static/10b6d8c8/images/none.gif' height=16 width=1>Signature verification failed in the update center 'default' <a href='#' class='showDetails'>(show details)</a><pre style='display:none'>java.security.cert.CertPathValidatorException: timestamp check failed
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(Unknown Source)
at sun.security.provider.certpath.PKIXCertPathValidator.doValidate(Unknown Source)
(zip)

=> certificate should be renewed
=> as a workaround, we could be able to bypass signature validation