• Trespass. The concept of trespass is grounded in physical space that can be precisely delimited. What is the analog of physical space in a medium in which physical space has lost its traditional meaning? Before networking became common, the concept of trespass could be applied to an unauthorized user sitting at a terminal hard-wired to a mainframe. The terminal was located in a physical space, and the user's presence there, if unauthorized, clearly constituted trespass against the owner of that space (who was also usually the owner of the mainframe). But when computers are interconnected all over the world, and the user may be accessing the network from his or her home and thus may not be subject to the jurisdiction of any interested party, on what is the concept of trespass based? Perhaps the unauthorized execution of commands is sufficient, although this interpretation may be problematic when execution is possible without a remote log-in that clearly demarcates a point of (authorized or unauthorized) access.

  • Invasion of privacy. In a physical space, an invader of privacy may well leave tracks or other evidence that he or she has opened file cabinets or closets. In many electronic environments, it is easy to view files and directories without leaving any trace whatever. Thus, the owners of a computer that has been compromised may have no idea of what information the alleged invader has obtained. (At the same time, other computer systems maintain logs, and so a trace of at least some activities may exist, whereas espionage activity may take place with paper documents, access to which may not leave any observable traces.)

  • Destruction or theft of property. The concept of electronic property is complicated by the fact that it, like all intellectual property, is intangible. When physical property is stolen, the original owner no longer has use of that property. Likewise, when it is destroyed, the original owner must buy it again to replace it, thus incurring a cost that is comparable to the cost of initial acquisition. But when electronic property is stolen, the original owner may not even be aware of it because he or she still has the use of it. When electronic property is destroyed, and backups are available, it can be replaced at relatively low cost.20


The status of "low cost" as a relative descriptor must be emphasized. For example, restoring a large database from a backup could require considerable work, although the cost might still be much lower than the cost of reconstructing the database from scratch. Moreover, "restored" files often do not contain the most recent changes made to them (e.g., a file might be restored using the backup made yesterday, but such a backup would obviously not include changes made since yesterday). Even worse, the absence of recent changes might not be noted by the user. Finally, the backups themselves may not be entirely reliable, and so it may not be possible to restore the "backed-up" version of the file properly.

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