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- .\"
- .\" enigma (aka. crypt) man page written by Joerg Wunsch.
- .\"
- .\" Since enigma itself is distributed in the Public Domain, this file
- .\" is also.
- .\" "
- .Dd May 8, 2018
- .Dt ENIGMA 1
- .Os
- .Sh NAME
- .Nm enigma ,
- .Nm crypt
- .Nd very simple file encryption
- .Sh SYNOPSIS
- .Nm
- .Op Fl s
- .Op Fl k
- .Op Ar password
- .Nm crypt
- .Op Fl s
- .Op Fl k
- .Op Ar password
- .Sh DESCRIPTION
- The
- .Nm
- utility, also known as
- .Nm crypt
- is a
- .Em very
- simple encryption program, working on a
- .Dq 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.
- .Pp
- 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
- .Xr getpass 3 .
- This is the only safe way of providing it.
- .Pp
- Alternatively, the key can be provided as the sole command-line
- argument
- .Ar password
- when starting the program.
- Obviously, this way the key can easily be
- spotted by other users running
- .Xr ps 1 .
- As yet another alternative,
- .Nm
- can be given the option
- .Fl k ,
- and it will take the key from the environment variable
- .Ev 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
- .Xr ps 1 .
- Thus this option is mainly provided for compatibility with other
- implementations of
- .Nm .
- .Pp
- When specifying the option
- .Fl s ,
- .Nm
- modifies the encryption engine in a way that is supposed to make it a
- little more secure, but incompatible with other implementations.
- .Pp
- .Ss Warning
- The cryptographic value of
- .Nm
- is rather small.
- This program is only provided here for compatibility
- with other operating systems that also provide an implementation
- (usually called
- .Xr crypt 1
- there).
- For real encryption, refer to
- .Xr openssl 1 ,
- or
- .Xr gpg 1 Pq Pa ports/security/gnupg1 .
- .Sh ENVIRONMENT
- .Bl -tag -offset indent -width ".Ev CrYpTkEy"
- .It Ev CrYpTkEy
- used to obtain the secret key when option
- .Fl k
- has been given
- .El
- .Sh EXAMPLES
- .Bd -literal -offset indent
- man enigma | enigma > encrypted
- Enter key: (XXX \(em key not echoed)
- .Ed
- .Pp
- This will create an encrypted form of this man page, and store it in
- the file
- .Pa encrypted .
- .Bd -literal -offset indent
- enigma XXX < encrypted
- .Ed
- .Pp
- This displays the previously created file on the terminal.
- .Sh SEE ALSO
- .Xr gpg 1 Pq Pa ports/security/gnupg1 ,
- .Xr openssl 1 ,
- .Xr ps 1 ,
- .Xr getpass 3
- .Sh HISTORY
- Implementations of
- .Nm crypt
- are very common among
- .Ux
- operating systems.
- This implementation has been taken from the
- .Em Cryptbreakers Workbench
- which is in the public domain.
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