C++加密解密工具包：ccrypt
ccrypt 是一個用于文件和數據流加密解密的命令行工具包，主要設計用于替換標準 Linux/Unit 的 crypt 工具（因為它使用的是非常弱的加密算法）。ccrypt 基于 Rijndael 加密方法，這是美國政府所使用的高級加密標準之一，提供非常強大的安全性保證，同時也提供了兼容 crypt 工具的兼容模式。
安全加密和解密的文件和數據流。用法: ccrypt [mode] [options] [file...] ccencrypt [options] [file...] ccdecrypt [options] [file...] ccat [options] file...
模式: -e, --encrypt encrypt -d, --decrypt decrypt -c, --cat cat; decrypt files to stdout -x, --keychange change key -u, --unixcrypt decrypt old unix crypt files
選項: -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</pre>
