Hello,
I got the following error when I run Utils.java of chapter7.
Would you help me to fix this problem?

root@jim-laptop:/home/jim/Desktop/testCode# javac chapter7/Utils.java
./chapter7/Utils.java:27: cannot access org.bouncycastle.asn1.x509.V1TBSCertificateGenerat or
bad class file: /usr/lib/jvm/java-6-sun-1.6.0.00/jre/lib/ext/bcprov-jdk16-136.jar(org/bouncycastle/asn1/x509/V1TBSCertificateGenerator.class)
class file has wrong version 50.0, should be 49.0
Please remove or make sure it appears in the correct subdirectory of the classpath.
            V1TBSCertificateGenerator certGen = new V1TBSCertificateGenerator();
            ^
1 error

I'm not sure what's happening, but you would normally only see this message if you were trying to use a JDK 1.5 javac with a JDK 1.6 jar. You might want to check your environment.

Regards,

David

Thanks ! David, the problem is fixed !