Enigma 2.8 requires System 7.0 or later. It requires about three megabytes of memory, and about 400K of disk space. Norton Directory Assistance II has been reported to cause some problems, but nothing severe. There are no other known hardware or init conflicts. For users with older machines or users who won't upgrade to System 7, you can get a copy of Enigma 1.2 by writing to the same address as those registering Enigma 2.7 Enigma 1.2 is compatible with all Macintosh's with at least 512K of RAM and the 128K ROM. Enigma 1.2 contains most of the encryption capability of Enigma 2.8 but does not support vaults.