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ccrypt |
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I love ccrypt; it is easy to use and does exactly what one wants from
an enrcyption program. Furthermore it's quite fast. It's a wonder
the program isn't more widely known. |
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ccrypt is a utility for encrypting and decrypting files and
streams. It was designed as a replacement for the standard unix crypt
utility, which is notorious for using a very weak encryption
algorithm. ccrypt is based on the Rijndael cipher, which is
the U.S. government's chosen candidate for the Advanced Encryption
Standard (AES, see http://www.nist.gov/aes). This
cipher is believed to provide very strong security.
Unlike unix crypt, the algorithm provided by ccrypt is not symmetric, i.e., one must specify whether to encrypt or decrypt. The most common way to invoke ccrypt is via the commands ccencrypt and ccdecrypt. There is also a ccat command for decrypting a file directly to the terminal, thus reducing the likelihood of leaving temporary plaintext files around. In addition, there is a compatibility mode for decrypting legacy unix crypt files. An emacs mode is also supplied for editing encrypted text files. Encryption and decryption depends on a keyword (or key phrase) supplied by the user. By default, the user is prompted to enter a keyword from the terminal. Keywords can consist of any number of characters, and all characters are significant (although ccrypt internally hashes the key to 256 bits). Longer keywords provide better security than short ones, since they are less likely to be discovered by exhaustive search. For a detailed description of the encryption algorithm used by ccrypt, see the man page. |
| I often receive questions from users about ccrypt. I have written up the answers to some Frequently Asked Questions. |
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For changes prior to version 1.8, see the file NEWS.
For a more detailed list of changes, see the ChangeLog.
October 18, 2012: Release 1.10. This release fixes a number of minor portability issues and minor bugs. The ccrypt core functionality has been factored into a convenience library libccrypt.a. A ccguess program was added to assist in the recovery of mistyped keys. Improved error checking and fixed minor compiler warnings. Minor improvements to emacs support, and added a --disable-emacs configuration option. Thanks to bornlibra23 and Johannes Ruscheinski for bug reports. August 28, 2009: Release 1.9. This release fixes a number of portability issues. There is no change in functionality relative to release 1.8. However, compilation errors on several platforms have been fixed, including Mac OSX, Ubuntu, FreeBSD, and Solaris 10. Also, rudimentary OS/2 support via EMX has been added. Thanks to Lester Ingber, Elbert Pol, and Michael Annino for reporting problems and helping to fix them. June 5, 2009: Release 1.8. This long-overdue release fixes some minor bugs and adds minor features. Added a new --keyref option to avoid double password prompt. Added a new exit code in case the key was not entered or not found. Added internationalization support and German and French translations. Fixed minor bugs in user interface and updated emacs support. Password files ending in a DOS-style end-of-line marker are now correctly recognized. Improved portability and testing. |
You have three different options for installing ccrypt:
(2) For the most current version of the Debian package, see the Debian ccrypt page. Debian (this includes Ubuntu) has a centralized package management system and users may run "apt-get install ccrypt" as root to install. (3) Solaris Packages supplied by Steve Christensen. See sunfreeware.com for additional packages. (4) OS/2 Package supplied by Elbert Pol. (5) SuSE RPMs supplied by Harry Auschner. (6) OpenBSD Package supplied by Kevin Lo. |
ccrypt 1.10. Secure encryption and decryption of files and streams.
Usage: ccrypt [mode] [options] [file...]
ccencrypt [options] [file...]
ccdecrypt [options] [file...]
ccat [options] file...
Modes:
-e, --encrypt encrypt
-d, --decrypt decrypt
-c, --cat cat; decrypt files to stdout
-x, --keychange change key
-u, --unixcrypt decrypt old unix crypt files
Options:
-h, --help print this help message and exit
-V, --version print version info and exit
-L, --license print license info and exit
-v, --verbose print progress information to stderr
-q, --quiet run quietly; suppress warnings
-f, --force overwrite existing files without asking
-m, --mismatch allow decryption with non-matching key
-E, --envvar var read keyword from environment variable (unsafe)
-K, --key key give keyword on command line (unsafe)
-k, --keyfile file read keyword(s) as first line(s) from file
-P, --prompt prompt use this prompt instead of default
-S, --suffix .suf use suffix .suf instead of default .cpt
-s, --strictsuffix refuse to encrypt files which already have suffix
-F, --envvar2 var as -E for second keyword (for keychange mode)
-H, --key2 key as -K for second keyword (for keychange mode)
-Q, --prompt2 prompt as -P for second keyword (for keychange mode)
-t, --timid prompt twice for encryption keys (default)
-b, --brave prompt only once for encryption keys
-y, --keyref file encryption key must match this encrypted file
-r, --recursive recurse through directories
-R, --rec-symlinks follow symbolic links as subdirectories
-l, --symlinks dereference symbolic links
-T, --tmpfiles use temporary files instead of overwriting (unsafe)
-- end of options, filenames follow
For detailed usage information, see the man
page.
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ccrypt comes with an emacs package for reading and writing
encrypted files. (Note that this package currently only works with
emacs, not with xemacs.) The package is called ps-ccrypt, and it is
based directly on the jka-compr package which is part of GNU
Emacs. Unlike previous versions of this package, it can be used in
addition to, and not instead of, jka-compr, to handle both encrypted
and compressed files. (However, files that are both encrypted and
compressed are not currently handled correctly).
To use the package, simply load ps-ccrypt and edit as usual. When you open a file with the ".cpt" extension, emacs will prompt you for a password for the file. It will remember the password for the buffer, and when you save the file later, it will be automatically encrypted again (provided you save it with a ".cpt" extension). Except for the password prompt, the operation of the package should be transparent to the user. The command M-x ccrypt-set-buffer-password can be used to change the current password of a buffer. The simplest way to use this package is to include the lines
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The following is a list of software related to ccrypt. The list is not
comprehensive; please let me know if you know of other such programs.
Note that I have not tried most of these programs. Use them at your
own risk.
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| Copyright © 2000-2012 Peter Selinger. |
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This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
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