Abstract: When data is stored on a computer, or subsequently, originator preferences relating to the data are stored in a database, for example in a network. When another user subsequently makes a request for processing of the received data, or a modified copy of the data, it is determined whether the requested processing is consistent with any stored originator preferences, and the requested processing is permitted only if it is consistent with the stored originator preferences. The preferences may relate to saving, copying or retransmitting the data. The originator may be notified of any processing operations that are carried out.

Abstract: A method is disclosed, for recognizing whether some electronic data is the digital representation of a piece of text and, if so, in which character encoding it has been encoded. A fingerprint is constructed from the data, wherein the fingerprint comprises, for each of a plurality of predetermined character encoding schemes, at least one confidence value, representing a confidence that the data was encoded using said character encoding scheme. The fingerprint also comprises a frequency value for each of a subset of byte values, each frequency value representing the frequency of occurrence of a respective byte value in the data. A statistical classification of the data is then performed based on the fingerprint.

Abstract: An email policy is applied in a policy manager, running on a mail server in a local area network, to determine whether an outgoing email message should be allowed to be transmitted to a destination address outside the local area network, for example over the internet. A digital signature is used in the policy manager, to determine if the sender is the sender indicated in the message itself. If so, a sender-dependent policy is applied.

Abstract: A method of controlling a system of monitoring messages in a network is described. A message sent by a user of the network to one or more recipients is received and a weight is applied to any text from any previous message that appears in the message. A measure of language content used in the message is formed and stored in one or more data stores. Information identifying the sender of the message is also stored. The stored measure of the language content and the stored information identifying the sender is reported to an administrator of the system.

Abstract: A method for monitoring electronic mail messages, each mail message comprising header information and a main body, particularly for protection against virus attacks and unsolicited commercial email (UCE). The method comprises generating a summary digest of only the subject line and the message content of the main body, wherein the message content may comprise textual content and/or attached files. The generated summary digest is stored in a memory, and compared with existing summary digests stored in memory. If the number of matches exceeds a threshold value, an alert signal is raised and appropriate action initiated. A timestamp may be stored with each summary digest, together with sender/recipient details and the internet protocol (IP) address of origin, to aid detection of the originator of the message.

Abstract: A method of controlling a system of monitoring messages in a network is described. A message sent by a user of the network to one or more recipients is received and a weight is applied to any text from any previous message that appears in the message. A measure of language content used in the message is formed and stored in one or more data stores. Information identifying the sender of the message is also stored. The stored measure of the language content and the stored information identifying the sender is reported to an administrator of the system.

Abstract: A method of processing a received image file, comprises receiving the image file; and detecting a match between the received image file and a previously received image file, if (a) the received image file differs from the previously received image file, and (b) an image represented by the received image file is visually identical to an image represented by the previously received image file.