不知道大家用过没用过 GnuPG 。GnuPG是GNU提供的用于安全通信和数据保存的工具。它可以用来对数据进行加密，也可以产生数字签名。在工具包中还包括了一个高级密钥管理工 具。（注意，GnuPG不和PGP2兼容，因为PGP2采用了有版权限制的加密算法）GnuPG使用的缺省算法是DSA和ElGamal；同步 (Symmetric)算法是：3DES、Blowfish、CAST5和Twofish；摘要算法是：MD5、RIPEMD160和SHA1。由于是 GPL版权所以大家可以安心使用

LINUX下安装: 

1.下载： 
在 http://www.gnupg.org/可找到下载文件并有最新消息或直接用下面路径下载 
ftp://ftp.gnupg.org/gcrypt/gnupg/gnupg-1.0.6.tar.gz 
MD5 checksums: 
7c319a9e5e70ad9bc3bf0d7b5008a508 gnupg-1.0.6.tar.gz 
71ae7d725776688c2e095d9672f38e61 gnupg-1.0.5-1.0.6.diff.gz 

2.解压: 

$tar xvzf gnupg-1.0.6.tar.gz 

3.安装： 

$cd gnupg-1.0.6 
$./configure 
默认安装目录是 /usr/local/bin 可以自己定制加入 --prefix=/dir 
$make 
$make install 

Windows 下安装: 

1. 解开压缩包最好在C:Gnupg目录(或是你喜欢的目录) 

2. 如果你是用的C:Gnupg在注册表中加入下面的键HKEY_CURRENT_USERSoftwareGNUGnuPGHomeDir值等于C:Gnupg 

3. 在运行或命令行模式下敲入gpg看是否运行.(建议在环境变量中加入路径,这样可以在任何目录运行gpg了) 

使用方法 创建密钥对: 

$gpg --gen-key 

Please select what kind of key you want: 加密方式 

(1) DSA and ElGamal (default) 
(2) DSA (sign only) 
(4) ElGamal (sign and encrypt)

Your selection? 1 
DSA keypair will have 1024 bits. 密钥长度我觉的1024就可以了 
About to generate a new ELG-E keypair. 如果你对加密有要求那就选2048 
minimum keysize is 768 bits 
default keysize is 1024 bits 
highest suggested keysize is 2048 bits 
What keysize do you want? (1024) 2048 
Do you really need such a large keysize? y 
Requested keysize is 2048 bits 
Please specify how long the key should be valid. 生命期0为无限 
0 = key does not expire 
= key expires in n days 
w = key expires in n weeks 
m = key expires in n months 
y = key expires in n years 
Key is valid for? (0) 
Key does not expire at all 
Is this correct (y/n)? y 

You need a User-ID to identify your key; the software constructs the user id 
from Real Name, Comment and Email Address in this form: 
"Heinrich Heine (Der Dichter) " 

Real name: ricktan 填写用户信息 
Email address: ricktan@sina.com.cn 
Comment: GPG test! 
You selected this USER-ID: 
"ricktan (GPG test!) " 

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O 
You need a Passphrase to protect your secret key. 

Enter passphrase:         验证密码加解密是用 
Repeat passphrase: 

We need to generate a lot of random bytes. It is a good idea to perform 
some other action (work in another window, move the mouse, utilize the 
network and the disks) during the prime generation; this gives the random 
number generator a better chance to gain enough entropy. 

这样密钥对就生成了。我们可以自行对照PGP产生钥匙对的方式，简单说明其它指令的使用方式，而指令其中的可以键入user ID的某些部份即可，例如user ID是ricktan ， 那么可以键入ricktan或sina等。 

gpg --export [--armor] # outfile 取出的公开钥匙至 outfile中。 
gpg --import [keyfile] 将公开钥匙[keyfile]加入钥匙环中。 
gpg -k 列印出公开钥匙。 
gpg -e -r file 加密file至binary档file.gpg中。 
gpg -e -r --armor file 加密file至ASCII档file.asc中。 
gpg -s file 加签file至binary档file.gpg中。 
gpg -s --armor file 加签file至ASCII档file.asc中。 
gpg -se -r file 加密加签file至binary档file.gpg中。 
gpg -se -r [-armor] file 加密加签file至ASCII档file.asc中。 
gpg -v file 解密file。 

例: 

加密文件test.doc 
gpg -e -r ricktan test.doc 
You need a passphrase to unlock the secret key for 
user: "ricktan (GPG test!) " 
1024-bit DSA key, ID 6541D744, created 2001-10-12 
Enter passphrase: 
会生成test.gpg文件删掉test.doc文件加密完成. 

解开文件: 
gpg -v test.gpg 

还有一个重要的事一定要删掉加密后的原始文件，要不就和没加密一样了:)这样加密后基本上是无法破解的所以密钥一定不能丢.对有的系统要求有比较大的随机数,windows版没有这个问题.要是不能生成密钥对成就将这个选项在编译前 

关掉 --enable-static-rnd=none 
该选项内容如下: 

--enable-static-rnd= Force the use of the random byte gathering 
module . Default is either to use /dev/random 
or the standard Uix module. Value for name: 
egd - Use the module which accesses the 
Entropy Gathering Daemon. See the webpages 
for more information about it. 
unix - Use the standard Unix module which does not 
have a very good performance. 
linux - Use the module which accesses /dev/random. 
This is the first choice and the default one 
for GNU/Linux or *BSD. 
none - Do not linkl any module in but rely on 
a dynmically loaded modules.