非对称加密 （公钥加密私钥解密或者公钥解密私钥加密）

非对称加密

 

非对称加密有一对密钥，公钥和私钥。可以用公钥加密，也可以用私钥加密。不过，公钥加密必须用私钥解密，私钥加密必须用公钥解密。如果不对应，则会报这样的异常

javax.crypto.BadPaddingException: Data must start with zero

 

 

代码如下：

 

import java.security.KeyPair;
import java.security.KeyPairGenerator;
import javax.crypto.Cipher;

public class test1 {

	//公钥加密
	public byte[] PublicEncrypt(KeyPair key,String str)throws Exception {
	    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
	    cipher.init(Cipher.ENCRYPT_MODE, key.getPublic());
	    return cipher.doFinal(str.getBytes("UTF8"));
	}
	
	//公钥解密
	public byte[] PublicDECRYPT (KeyPair key,byte[]  data)throws Exception {
	    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
	    cipher.init(Cipher.DECRYPT_MODE, key.getPublic());
	    return cipher.doFinal(data);
	}
	
	//私钥加密
	public byte[] PrivateEncrypt (KeyPair key,String str)throws Exception {
	    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
	    cipher.init(Cipher.ENCRYPT_MODE, key.getPrivate());
	    return cipher.doFinal(str.getBytes("UTF8"));
	}
	
	//私钥解密
	public byte[] PrivateDECRYPT(KeyPair key,byte[]  data)throws Exception  {
	    Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
	    cipher.init(Cipher.DECRYPT_MODE, key.getPrivate());
	    return cipher.doFinal(data);
	}

    
	public static void main(String args[]) throws Exception {
		String str = "Hello World!";
		KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
	    keyGen.initialize(1024);
	    KeyPair key = keyGen.generateKeyPair();
		test1 t = new test1();
		System.out.println("加密前原文:"+str);
		byte[] data = t.PublicEncrypt(key,str); 
		System.out.println("私钥解密后:"+new String(t.PrivateDECRYPT(key,data)));
		byte[] data1 = t.PrivateEncrypt(key,str); 
		System.out.println("公钥解密后:"+new String(t.PublicDECRYPT(key,data1)));
	}
}

评论

4 楼 lijunwyf41 2014-02-25  

RSA 加密解密 Data must start with zero 对这个问题，你试试

ciphertext = URLDecoder.decode(ciphertext,"UTF-8").replace(' ', '+');

3 楼 me- 2013-07-30  

   good 

2 楼 me- 2013-07-30  

xiexie

1 楼 eisenhower 2012-02-21