Although a system audit can be conducted alongside the financial audit or internal audit, both these audits are like chalk and cheese. While financial audit requires journals, vouchers and bills kind of documents as sources of evidence to come up with final audit papers. System audit, on the other hand, uses the encryption used, the firewall, authorized users and password protection as sources of evidence to generate the final report. This difference in the nature of system audit calls for CISA qualified accountants to perform a separate audit.