The condition that would be of most concern to an IS auditor assessing the risk of a successful brute force attack against encrypted data at rest is short key length. A brute force attack is a method of breaking encryption by trying all possible combinations of keys until finding the correct one. The shorter the key length, the easier it is for an attacker to guess or crack the encryption. Random key generation, use of symmetric encryption, and use of asymmetric encryption are not conditions that would increase the risk of a successful brute force attack. In fact, random key generation can enhance security by preventing predictable patterns in key selection. Symmetric encryption and asymmetric encryption are different types of encryption that have their own advantages and disadvantages, but neither is inherently more vulnerable to brute force attacks than the other. References: CISA Review Manual (Digital Version): Chapter 5 - Information Systems Operations and Business Resilience