Information availability is the third part of the CIA triad. Availability
means that information can be accessed and modified by anyone
authorized to do so in an appropriate time frame. Depending on the type
of information, appropriate time frame can mean different things. For
example, a stock trader needs information to be available immediately,
while a salesperson may be happy to get sales numbers for the day in a
report the next morning. Companies such as Amazon.com will require
their servers to be available 24 hours a day, 7 days a week. Other
companies may not suffer if their web servers are down for a few minutes
once in a while.
Tools for Information Security
In order to ensure the confidentiality, integrity, and availability of
information, organizations can choose from a variety of tools. Each of
these tools can be utilized as part of an overall information‐security
policy, which will be discussed in “Security Policies.”