一.rsa演算法介紹：百度百科

二.首先通過rsa演算法生成一對公私鑰

 private static void generateKeyPair() throws Exception{
        Security.addProvider(new com.sun.crypto.provider.SunJCE());
        /** RSA演算法要求有一個可信任的隨機數源 */
        SecureRandom sr = new SecureRandom();
        /** 為RSA演算法建立一個KeyPairGenerator物件 */
        
        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
        /** 利用上面的隨機資料來源初始化這個KeyPairGenerator物件 */
        kpg.initialize(4096, sr);
        /** 生成密匙對 */
        KeyPair kp = kpg.generateKeyPair();
        /** 得到公鑰 */
        Key publicKey = kp.getPublic();
        /** 得到私鑰 */
        Key privateKey = kp.getPrivate();
    
        /** 用物件流將生成的金鑰寫入檔案 */
        ObjectOutputStream oos1 = new ObjectOutputStream(new FileOutputStream(ResourceBundleUtil.getSystem(WYPublicKey)/*"yxb_ok_publickey.keystore"*/));
        ObjectOutputStream oos2 = new ObjectOutputStream(new FileOutputStream(ResourceBundleUtil.getSystem(WYPrivateKey)/*"text_privatekey.keystore"*/));
        oos1.writeObject(publicKey);
        oos2.writeObject(privateKey);
        /** 清空快取，關閉檔案輸出流 */
        oos1.close();
        oos2.close();
    }
 

三.對字串進行分段加密操作

    1.進行加密操作

public static String encrypt(String source,String publickey) throws Exception{   //source為需要加密的對應  publickey-rsa公鑰
    	  
    	  /** 將檔案中的公鑰物件讀出 */
    	ObjectInputStream ois = new ObjectInputStream(RsaUtil.class.getResourceAsStream("/"+publickey));
    	Key key = (Key) ois.readObject();
        ois.close();
        /** 得到Cipher物件來實現對源資料的RSA加密 */
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, key);
       byte[] b = source.getBytes("utf-8");
      
        byte[] b1 = null;
        /** 執行加密操作 */
        for (int i = 0; i < b.length; i += 501) {  
       	byte[] doFinal  = cipher.doFinal(ArrayUtils.subarray(b, i,i + 501));      
        	b1 = ArrayUtils.addAll(b1, doFinal);  
        }
    	BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(b1);      
        
    }
 

2.對加密後引數進行對應的解密：

public static String decrypt(String cryptograph,String privatekey) throws Exception{ //cryptograph-通過rsa公鑰加密得到的引數  privatekey-與公鑰對應的私鑰
    	 /** 將檔案中的私鑰物件讀出 */
    	// cryptograph= new String(cryptograph.getBytes(),"gbk");
    	ObjectInputStream ois = new ObjectInputStream(RsaUtil.class.getResourceAsStream("/"+privatekey));
        Key key = (Key) ois.readObject();
        /** 得到Cipher物件對已用公鑰加密的資料進行RSA解密 */
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, key);
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] b1 = decoder.decodeBuffer(cryptograph);
        /** 執行解密操作 */
        byte[] b = null;
        
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < b1.length; i += 512) {
       	byte[] doFinal = cipher.doFinal(ArrayUtils.subarray(b1, i, i + 512));    
       	sb.append(new String(doFinal,"utf-8"));
       }
        return sb.toString();

    }
 

3.測試方法

 public static void main(String[] args) throws Exception {
    	
    	String a = "abc";
    	String b = encrypt(a,"yxb_ok_publickey.keystore");
    	String c = decrypt(b,"yxb_ok_privatekey.keystore");
    	System.out.println("加密前的引數："+a);
    	System.out.println("加密後的引數為："+b);
    	System.out.println("解密後的引數："+c);

}  

4.執行結果為：

5.專案匯入的包為：

import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Security;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import javax.crypto.Cipher;

import org.apache.commons.lang3.ArrayUtils;
import org.apache.xml.security.utils.Base64;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;