I have an applet, embedded in a web page, that worked fine (and still
works fine) on machines running Java 1.4.2 and below, but throws an
exception on machines running version 1.5.0_0x. Specifically, I get the
following exception and stack trace:

java.security.cert.CertificateException: Check leaf key usage failed in
certificate
     at com.sun.deploy.CertUtils.checkUsageForCodeSigning(Unknown
source)
     ...



I'm totally new to signed applets, so I have no clue what "check leaf
key usage" is or why it failed in the certificate. I also can't figure
out why it didn't fail in 1.4.2 and failed in 1.5.0. Does anybody have
some ideas how I can get my applet back up and running?

Thanks.

--Jay

I had the same problem but with a signed application and WebStart
(worked fine in 1.4.x, but was rejected by 1.5 with the same exception
you're seeing).

The problem was due to the fact that I was signing the application with
a certificate that wasn't suitable for code-signing. It was an SSL
certificate (SSL certificates don't have code-signing extensions).

You need to make sure you're signing your applet with a certificate that
is suitable for code signing. Note that jarsigner in 1.4 and 1.5 will
happily sign your code with an unsuitable certificate without indicating
that there might be a problem. (They will both even verify that the jar
has been signed.)

Damian



jayharris@gmail.com wrote:
> I have an applet, embedded in a web page, that worked fine (and still
> works fine) on machines running Java 1.4.2 and below, but throws an
> exception on machines running version 1.5.0_0x. Specifically, I get the
> following exception and stack trace:
> 
> java.security.cert.CertificateException: Check leaf key usage failed in
> certificate
>      at com.sun.deploy.CertUtils.checkUsageForCodeSigning(Unknown
> source)
>      ...
> 
> 
> 
> I'm totally new to signed applets, so I have no clue what "check leaf
> key usage" is or why it failed in the certificate. I also can't figure
> out why it didn't fail in 1.4.2 and failed in 1.5.0. Does anybody have
> some ideas how I can get my applet back up and running?
> 
> Thanks.
> 
> --Jay
>