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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 1.5, see the file NEWS.
For a more detailed list of changes, see the ChangeLog.
Feburary 4, 2008: There is a new emacs package ps-ccrypt.el. Unlike the previous package jka-compr-ccrypt.el, this can be loaded in addition to, rather than instead of, jka-compr.el. November 29, 2006: AIX precompiled distribution updated. Large file support is now enabled in AIX. Thanks to Jon Hardt for reporting this bug. January 13, 2005: AIX precompiled distribution updated. Thanks to Adrien Cuypers for reporting a bug in the previous distribution. March 28, 2004: Release 1.7. Large file support now works under cygwin. Prompting twice for encryption passwords is now the default. Added --disable-libcrypt option for systems where libcrypt is broken. August 26, 2003: Release 1.6. Fixed a potential (but rare) segmentation fault. August 25, 2003: Release 1.5. Numerous improvements to the code and some bug fixes. --mismatch option now works again. Ccrypt now also compiles under the gcc-3.3 compiler and the cc compiler. Return values were made more meaningful. Autoconfiguration has been improved, and a new --with-lispdir configuration option was added. The "check" target has been improved to work on more machines. Some bugs in emacs support were fixed. |
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Ccrypt is built from sources using the standard configure/make
commands. Please see the file INSTALL for detailed
instructions. Binary distributions are available for a number of
popular platforms; please see the file README for
some hints on how to install the binaries. Windows users please see
the file README.win. Redhat packages are also
available for users of the Redhat Package Manager. If you would like
to ensure the accuracy of the downloaded files, you can double-check
their SHA1 sums.
(2) SuSE RPMs supplied by Harry Auschner. (3) For the most current version of the Debian package, see the Debian ccrypt page. (4) OpenBSD Package supplied by Kevin Lo. |
ccrypt 1.7. 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
-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 jka-compr-ccrypt, and
it is based directly on the jka-compr package which is part of GNU
Emacs. It handles both encrypted and compressed files (although
currently not encrypted compressed files).
To use the package, simply load jka-compr-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 package also handles compressed ".gz", ".bz2", and ".Z" files, and it should be used instead of, not in addition to, jka-compr. 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.
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| 1.7 |
| Copyright © 2000-2004 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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