ENIGMA(1)

NAME
enigma, crypt - very simple file encryption

SYNOPSIS
enigma [-s] [-k] [password]
crypt [-s] [-k] [password]

DESCRIPTION
Enigma, also known as crypt is a very simple encryption program, working on a “secret-key” basis. It operates as a filter, i. e. it encrypts or decrypts a stream of data from standard input, and writes the result to standard output. It automatically detects whether the input data stream is already encrypted, and switches into decryption mode in this case.

There are several ways to provide the secret key to the program. By default, the program prompts the user on the controlling terminal for the key, using getpass(3). This is the only safe way of providing it.

Alternatively, the key can be provided as the sole command-line argument password when starting the program. Obviously, this way the key can easily be spotted by other users running ps(1). As yet another alternative, enigma can be given the option -k, and it will take the key from the environment variable CrYpTkEy. While this at a first glance seems to be more secure than the previous option, it actually isn't since environment variables can also be examined with ps(1). Thus this option is mainly provided for compatibility with other implementations of enigma.

When specifying the option -s, enigma modifies the encryption engine in a way that is supposed to make it a little more secure, but incompatible with other implementations.

  Warning
The cryptographic value of enigma is rather small. This program is only provided here for compatibility with other operating systems that also provide an implementation. For real encryption, refer to bdes(1) (from the DES distribution package), or pgp(1) (from the ports collection). However, restrictions for exporting, importing or using such tools might exist in some countries, so those stronger programs are not being shipped as part of the operating system by default.

ENVIRONMENT

CrYpTkEy
    used to obtain the secret key when option -k has been given

EXAMPLES

    man enigma | enigma > encrypted
    Enter key: (XXX — key not echoed)

This will create an encrypted form of this man page, and store it in the file ‘encrypted’.

    enigma XXX < encrypted

This displays the previously created file on the terminal.

SEE ALSO
bdes(1), pgp(1), ps(1), getpass(3)

HISTORY
Implementations of crypt are very common among UNIX operating systems. This implementation has been taken from the Crypt Breaker's Workbench which is in the public domain.