Control Identification and Design
An IS auditor needs to have a sufficient understanding of the various control techniques used while designing applications. In the next few sub-sections, you will go through some of the important controls built into an application system.
Check Digits
A check digit is an extra digit used for error detection. A check digit is arrived at by a mathematical algorithm. It is added to the original data to ensure that data is not altered.
By ensuring that the original data is not tampered with or altered, check digits help prevent transposition and transcription errors. The most widely used example of the use of a check digit is 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 the...
