Abstract: Files stored on a hard disk drive are scanned for a predefined pattern, such as a virus definition. For each one of a plurality of files, predetermined select portion(s) (e.g., likely sites of infection) are stored in a common file. After storing the predetermined select portions, the portions are tested without accessing the file to determine whether content of the predetermined select portion corresponds to the predefined pattern.

Abstract: Receiver access to a secure communication is determined by the sender. The sender defines an access parameter, such as number of times a message can be decrypted, expiration time of message, or some contingent event that triggers expiration of a message. A send configuration module defines the encryption method, encryption key length, and the control parameter(s). A key management module serves to implement the send configuration parameters during a communication. Upon receiving a message the receiver module contacts the key management module to request a decryption key. The key management module returns the decryption key or a ‘denied’ message. Once the message is decrypted at the receiver, the key and the decrypted source are deleted from the receiver computer. The message is displayed in a bit-mapped window.