http://java.sun.com/j2se/1.5.0/docs/api/java/security/cert/CertificateFactory.html#generateCertificate(java.io.InputStream)
http://java.sun.com/j2se/1.5.0/docs/api/java/security/cert/X509Certificate.html#getNotBefore()
http://java.sun.com/j2se/1.5.0/docs/api/java/security/cert/X509Certificate.html#getNotAfter()