Flow control
– prevents information from flowing in such a way that it reaches
unauthorized users.
– Channels that are pathways for information to flow implicitly in ways
that violate the security policy of an organization are called covert
channels.
• Data encryption
– protect sensitive data (such as credit card numbers) that is transmitted
via some type of communications network.
– Encryption can be used to provide additional protection for sensitive
portions of a database as well. The data is encoded using some coding
algorithm.
– An unauthorized user who accesses encoded data will have difficulty
deciphering it, but authorized users are given decoding or decrypting
algorithms (or keys) to decipher the data.
– Encrypting techniques that are very difficult to decode without a key
have been developed for military applications.