Abstract: A CD-ROM has an obscurable section wherein exists a photosensitive mask material layer or constituent operative to alter the optical properties of areas subjected to prolonged exposure to the CD-ROM read laser radiation. Digital information stored on a CD-ROM is made accessible by use of a password, which is generated from user machine unique information, and which is written on the CD-ROM via selective exposure of the CD-ROM to the radiation used to read the CD-ROM.

Abstract: The present invention is a method and system for preventing and/or tracking unauthorized copying or distribution of downloaded software. In general, the software is tagged with user identifying and/or platform-identifying information, preferably in coded form, both to allow a validation check to determine whether a particular platform is authorized and to trace a pirated copy to its original authorized user. The platform-identifying information is preferably placed in numerous locations, some of which may be used for the validation check, others of which may not be. In addition, other information usable to identify an original user or purchaser may be embedded within the material of interest. Several alternative methods of tagging the software may be used depending upon whether the particular portion being tagged comprises executable or non-executable content.

Abstract: Digital information stored on a CD-ROM is accessible by use of a password, which is readable initially on the CD-ROM and which subsequently becomes at least partially unreadable due to exposure of the CD-ROM to the radiation used to read the CD-ROM. A user machine which read the password before the password became at least partially unreadable may subsequently use it to access encrypted information on the CD-ROM, while a user machine which has not read the password before it became at least partially unreadable will be unable subsequently to read the password, and hence unable to access encrypted information on the CD-ROM.