Android之RAS加密算法测试实例

import java.security.key;  
import java.security.keyfactory;  
import java.security.keypair;  
import java.security.keypairgenerator;  
import java.security.privatekey;  
import java.security.publickey;  
import java.security.interfaces.rsaprivatekey;  
import java.security.interfaces.rsapublickey;  
import java.security.spec.pkcs8encodedkeyspec;  
import java.security.spec.x509encodedkeyspec;  

import javax.crypto.cipher;  

import sun.misc.base64decoder;  
import sun.misc.base64encoder;  

   
public class rsahelper {  

       
      public static publickey getpublickey(string key) throws exception {  
            byte[] keybytes;  
            keybytes = (new base64decoder()).decodebuffer(key);  

            x509encodedkeyspec keyspec = new x509encodedkeyspec(keybytes);  
            keyfactory keyfactory = keyfactory.getinstance("rsa");  
            publickey publickey = keyfactory.generatepublic(keyspec);  
            return publickey;  
      }  

      public static privatekey getprivatekey(string key) throws exception {  
            byte[] keybytes;  
            keybytes = (new base64decoder()).decodebuffer(key);  

            pkcs8encodedkeyspec keyspec = new pkcs8encodedkeyspec(keybytes);  
            keyfactory keyfactory = keyfactory.getinstance("rsa");  
            privatekey privatekey = keyfactory.generateprivate(keyspec);  
            return privatekey;  
      }  

       
      public static string getkeystring(key key) throws exception {  
            byte[] keybytes = key.getencoded();  
            string s = (new base64encoder()).encode(keybytes);  
            return s;  
      }  

   
      public static void main(string[] args) throws exception {  

            keypairgenerator keypairgen = keypairgenerator.getinstance("rsa");  
            //密钥位数  
            keypairgen.initialize(1024);  
            //密钥对  
            keypair keypair = keypairgen.generatekeypair();  

            // 公钥  
            publickey publickey = (rsapublickey) keypair.getpublic();  

            // 私钥  
            privatekey privatekey = (rsaprivatekey) keypair.getprivate();  

            string publickeystring = getkeystring(publickey);  
            system.out.println("public:\n" + publickeystring);  

            string privatekeystring = getkeystring(privatekey);  
            system.out.println("private:\n" + privatekeystring);  

            //加解密类  
            cipher cipher = cipher.getinstance("rsa");//cipher.getinstance("rsa/ecb/pkcs1padding");  

            //明文  
            byte[] plaintext = "我们都很好！邮件：@sina.com".getbytes();  

            //加密  
            cipher.init(cipher.encrypt_mode, publickey);  
            byte[] enbytes = cipher.dofinal(plaintext);  

           //通过密钥字符串得到密钥  
            publickey = getpublickey(publickeystring);  
            privatekey = getprivatekey(privatekeystring);  

            //解密  
            cipher.init(cipher.decrypt_mode, privatekey);  
            byte[]debytes = cipher.dofinal(enbytes);  

            publickeystring = getkeystring(publickey);  
            system.out.println("public:\n" +publickeystring);  

            privatekeystring = getkeystring(privatekey);  
            system.out.println("private:\n" + privatekeystring);  

            string s = new string(debytes);  
            system.out.println(s);  

   
      }  

}