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ENIGMA(1) FreeBSD General Commands Manual ENIGMA(1)
NAME
enigma, crypt - very simple file encryption
SYNOPSIS
enigma [-s] [-k] [password]
crypt [-s] [-k] [password]
DESCRIPTION
The enigma utility, 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. Since its operation is fully symmetrical,
feeding the encrypted data stream again through the engine (using the
same secret key) will decrypt it.
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 is not
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 (usually called crypt(1) there). For real
encryption, refer to openssl(1), or gpg(1) (ports/security/gnupg1).
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
gpg(1) (ports/security/gnupg1), openssl(1), ps(1), getpass(3)