PRETTY GOOD ENVELOPE is a program suite for hiding a (binary) message in a larger binary file, and retrieving such a hidden message. The algorithm simply appends the message to the binary envelope file, and then puts the appended 4-byte pointer to the start of the message. To retrieve the message, the last 4 bytes of the file are read, the file pointer is set to that value, and the file is read from that point, excluding the last 4 pointer bytes.
PRETTY GOOD ENVELOPE is implemented so that it physically alters the envelope file as found on disk, rather than reading it and rewriting it. Full DOS file specification is supported, up to a maximum of 36 characters. When retrieving a message, you have complete control over the naming of the output file.
Any character in the command tail will cause this file to be output to the screen, provided it is either in the current directory or a directory in the DOS path specification. No options or file specs are supported in the command line except for this .doc file. PGE Version 1.0 was written by an author using the alias Roche'Crypt.