Control Identification and Design
An IS auditor needs to have a sufficient understanding of the various control techniques used while designing applications as they need to ensure that robust controls are implemented for security. In the next few subsections, you will go through some of the important controls built into an application system.
Check Digits
A check digit is an extra digit added to the original data to ensure that the data has not been altered; it is used to detect and prevent transposition and transcription errors. A check digit is usually arrived at by a mathematical algorithm.
The most widely used example of the use of a check digit is to verify the bank account numbers assigned to customers.
For instance, suppose a bank account number is 630000241453. The last digit, 3, is the check digit, and if the other numbers are correct, then the check digit calculation will produce 3:
- Add the numbers placed in odd digit positions: 6+0+0+2+1+5 = 14.
- Add...
