pki java相关代码参考

keytool -genkey -dname "CN=demo, OU=softDept, O=company,
L=puddong,S=shanghai, C=cn" -alias demo -keyalg RSA -keysize 1024
-keystore demoKeystore -validity 3650 -storepass storePwd -keypass
demoPwd

生成保存公钥和私钥的密钥仓库，保存在demoKeystore文件中。这里storepass 和 keypass
不要有java 正则表达式中的特殊字符，否则程序里要转义麻烦。

keytool -export -alias demo -keystore demoKeystore -rfc -file
demo.cer //从密钥仓库中导出保存公钥的证书

输入keypass 即demoPwd

try{

//
密钥仓库

KeyStore ks = KeyStore.getInstance("JKS");

//读取密钥仓库

FileInputStream
ksfis = new FileInputStream("demoKeystore");

BufferedInputStream
ksbufin = new BufferedInputStream(ksfis);

char[] storePwd =
"storePwd".toCharArray();

ks.load(ksbufin, storePwd);

ksbufin.close();

char[]
keyPwd = "demoPwd".toCharArray();

//从密钥仓库得到私钥

PrivateKey priK =
(PrivateKey) ks.getKey("demo", keyPwd);

//生成cipher

Cipher
cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding",new
org.bouncycastle.jce.provider.BouncyCastleProvider());

//用私钥初始化cipher

cipher.init(Cipher.ENCRYPT_MODE,
priK);

byte[] plain = "This is plain text".getBytes("UTF-8");

//
因为用的1024位rsa算法，一次只能加密1024/8-11字节数据，分开加密

byte[] code = new
byte[(((plain.length-1)/117+1))*128];

int ixplain = 0;

int ixcode = 0;

while((plain.length - ixplain) > 117)
{//每117字节做一次加密

ixcode += cipher.doFinal(plain,
ixplain, 117, code, ixcode);

ixplain += 117;

}

cipher.doFinal(plain, ixplain, plain.length - ixplain,
code, ixcode);

//加密后的code

System.out.println(Arrays.toString(code));

//通常会用base64编码

String base64 = encoder.encode(code);

CertificateFactory
certificatefactory = CertificateFactory

.getInstance("X.509");

//
读取证书

FileInputStream fin = new FileInputStream("demo.cer");

X509Certificate
certificate = (X509Certificate) certificatefactory

.generateCertificate(fin);

fin.close();

//
得到公钥

PublicKey pubK = certificate.getPublicKey();

//初始
化cipher

cipher.init(Cipher.DECRYPT_MODE, pubK);

//base64
解码

code = decoder.decodeBuffer(base64);

System.out.println(Arrays.toString(code));

byte[] plain2 =
new byte[code.length];

int ixplain2 = 0;

int ixcode2 = 0;

while((code.length - ixcode2) > 128)
{//每128字节做一次解密

ixplain2 += cipher.doFinal(code,
ixcode2, 128, plain2, ixplain2);

ixcode2 += 128;

}

ixplain2 += cipher.doFinal(code, ixcode2, code.length -
ixcode2, plain2, ixplain2);

String s2 = new
String(plain2, 0, ixplain2, "UTF-8");

System.out.println(s2);

}catch(Exception ex){

ex.printStackTrace();

}
http://www.blogjava.net/neumqp/archive/2006/03/02/33211.html