Alice sends a message to Bob that is intercepted by Trudy. Which scenario describes an availability violation?

The scenario that accurately depicts an availability violation is when Trudy deletes the message without reading or forwarding it. Availability in the context of information security refers to ensuring that authorized users have access to information and associated assets when required. By deleting the message, Trudy effectively prevents Bob from accessing the original communication from Alice, which disrupts the intended flow of information and denies Bob the ability to receive crucial content.

In contrast, the other scenarios do not directly compromise availability. For instance, if Trudy reads the message, that pertains more to confidentiality. If Bob receives the message late, it involves a delay, but not necessarily a total denial of access; he eventually does receive the message, albeit not in a timely manner. Additionally, Trudy modifying the message speaks to integrity, where the content has been altered and may mislead the recipient, but Bob still retains access to the message itself. Thus, option C is the most aligned with a violation of availability principles.