Computer systems are used by Licensed Persons to process large numbers of transactions and provide quality service to its customers. While efficiency of processing transactions is the main objective of computerizing operations of a Licensed Person, the security of customer information and related transaction data is vital. Licensed Persons must not compromise in introducing information security measures appropriate to the complexity and size of their business. This Chapter contains a few illustrative (but not exhaustive) security measures which all Licensed Persons must implement at a minimum at all times. Additional measures must be introduced depending on the size and the complexity of the business and considering the results of penetration tests and IT audits by external experts.