AESCrypt on FreeBSD 8.2

概要

AES (Rijndael) でファイルを暗号化・復号化する。但し、この程度の処理は既に openssl などでもできるため、わざわざインストールする必要はなかった（笑）。

DESCRIPTION
     The aescrypt utility encrypts data using the Rijndael algorithm, the win-
     ner of the Advanced Encryption Standard (AES) competition.  The encryp-
     tion is done in Cipher Block Feedback (CFB-128) mode, with the salt ran-
     domly generated from data read from the /dev/urandom device.  The plain-
     text data is read from standard input and the encrypted data is written
     to standard output.

     The encryption key may be read from standard input or from a file,
     depending on the argument passed to the -k command-line option.  If ``-''
     is used as a filename, the aescrypt utility reads as many hexadecimal
     digits as needed from standard input and then one additional byte to
     allow for a newline separating the key from the actual data to be
     encrypted.  If the filename is not ``-'', the aescrypt utility opens the
     specified file and reads text lines from it until a line starting with
     the characters kk= is reached.  Those characters should be immediately
     followed by as many hexadecimal digits as needed; the rest of the line,
     as well as the rest of the file, is ignored.

     The encryption key may be 128, 192, or 256 bits long.  By default, the
     aescrypt utility uses (and expects to read) a 128-bit key, unless a dif-
     ferent size is supplied by the -s keysize command-line option.

     The aescrypt utility reads 16 bytes (128 bits) from the /dev/urandom
     device to initialize the salt for the CFB-128 encryption.  The salt is
     prepended to the encrypted data in the output.

HISTORY
     The aescrypt utility was written by Eric Lee Green, and was modified to
     use Rijndael rather than Twofish by Randy Kaelber.  It uses the freely
     available Rijndael implementation by Antoon Bosselaers and Vincent
     Rijmen.  This manual page was written by Peter Pentchev in 2008.

AUTHORS
     The aescrypt utility - Eric Lee Green <eric@badtux.org>, Randy Kaelber
     <randyk@sourceforge.net>.

     The manual page - Peter Pentchev <roam@ringlet.net>.

インストール

例によって FreeBSD 8.2 release 上での操作を前提にする。/usr/ports/security/aescrypt に移動して、以下のとおり。

freebsd# make
===>  Vulnerability check disabled, database not found
===>  License check disabled, port has not defined LICENSE
=> aescrypt-0.7.tar.gz doesn't seem to exist in /usr/ports/distfiles/.
=> Attempting to fetch http://heanet.dl.sourceforge.net/project/aescrypt/aescrypt/0.7.0/aescrypt-0.7.tar.gz
aescrypt-0.7.tar.gz                           100% of   60 kB   23 kBps
=> aescrypt-0.7-roam-whopper-01.patch.gz doesn't seem to exist in /usr/ports/distfiles/.
=> Attempting to fetch http://devel.ringlet.net/security/aescrypt/patches/aescrypt-0.7-roam-whopper-01.patch.gz
aescrypt-0.7-roam-whopper-01.patch.gz         100% of 7418  B 1407  Bps
===>  Extracting for aescrypt-0.7_1
=> SHA256 Checksum OK for aescrypt-0.7.tar.gz.
=> SHA256 Checksum OK for aescrypt-0.7-roam-whopper-01.patch.gz.
===>  Patching for aescrypt-0.7_1
===>  Applying distribution patches for aescrypt-0.7_1
===>  Configuring for aescrypt-0.7_1
creating cache ./config.cache
checking for gcc... cc
checking whether the C compiler (cc -O2 -pipe -fno-strict-aliasing ) works... yes
checking whether the C compiler (cc -O2 -pipe -fno-strict-aliasing ) is a cross-compiler... no
checking whether we are using GNU C... yes
checking whether cc accepts -g... yes
checking how to run the C preprocessor... cpp
checking for ANSI C header files... yes
checking for fcntl.h... yes
checking for working const... yes
checking for size_t... yes
checking size of int... 4
checking size of long... 4
checking whether byte ordering is bigendian... no
updating cache ./config.cache
creating ./config.status
creating Makefile
creating config.h
===>  Building for aescrypt-0.7_1
cc -c -O2 -pipe -fno-strict-aliasing  aescmdline.c
cc -c -O2 -pipe -fno-strict-aliasing  bin2hex.c
cc -c -O2 -pipe -fno-strict-aliasing  dorandom.c
cc -c -Wall -W -O2 -DSTRICT_ALIGN=0 rijndael.c
rijndael.c: In function 'blockEncrypt':
rijndael.c:625: warning: suggest parentheses around arithmetic in operand of |
rijndael.c: In function 'blockDecrypt':
rijndael.c:645: warning: suggest parentheses around && within ||
rijndael.c:732: warning: suggest parentheses around arithmetic in operand of |
cc -c -O2 -pipe -fno-strict-aliasing  aescrypt.c
cc -c -O2 -pipe -fno-strict-aliasing  dstring.c
cc -O2 -pipe -fno-strict-aliasing  -o aescrypt aescrypt.o dorandom.o aescmdline.o bin2hex.o rijndael.o dstring.o
cc -c -O2 -pipe -fno-strict-aliasing  aesget.c
cc -O2 -pipe -fno-strict-aliasing  -o aesget aesget.o aescmdline.o bin2hex.o rijndael.o dstring.o
cc -O2 -pipe -fno-strict-aliasing  -o tobin bin2hex.o dstring.o tobin.c
gzip -c -9 aescrypt.1 > aescrypt.1.gz || rm -f aescrypt.1.gz
gzip -c -9 aesget.1 > aesget.1.gz || rm -f aesget.1.gz
freebsd# make install
===>  Installing for aescrypt-0.7_1
===>   Generating temporary packing list
===>  Checking if security/aescrypt already installed
install -c -s -o root -g wheel -m 555 aescrypt aesget /usr/local/bin/
install -c -o root -g wheel -m 444 aescrypt.1.gz aesget.1.gz /usr/local/man/man1/
/bin/mkdir -p /usr/local/share/doc/aescrypt
install  -o root -g wheel -m 444 /usr/ports/security/aescrypt/work/aescrypt-0.7/README.html /usr/local/share/doc/aescrypt
===>   Registering installation for aescrypt-0.7_1
freebsd#

使い方

SYNOPSIS

aescrypt -k keyfile [-s keysize]

とは言え、まず秘密鍵を用意しなければならない。秘密鍵のジェネレータは付属していないので、他に用意する。

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