Verify that the passed time is within the validity period.
@param now the Date against which to compare the validity
period.
@exception CertificateExpiredException if the certificate has expired
with respect to the <code>Date</code> supplied.
@exception CertificateNotYetValidException if the certificate is not
yet valid with respect to the <code>Date</code> supplied.
Verify that the passed time is within the validity period. @param now the Date against which to compare the validity period.
@exception CertificateExpiredException if the certificate has expired with respect to the <code>Date</code> supplied. @exception CertificateNotYetValidException if the certificate is not yet valid with respect to the <code>Date</code> supplied.