RSA分段加密解密

package com.sankuai.meituan.waimai.common;

import org.apache.commons.lang.ArrayUtils;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
import sun.security.rsa.RSAPrivateKeyImpl;
import sun.security.rsa.RSAPublicKeyImpl;
import sun.security.util.DerValue;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.util.HashMap;
import java.util.Map;

/**
 *  Date: 14-9-18
 * Time: 下午4:20
 */
public class RSAHelper {

    
    public static final int ENCODE_MAX = 117;
    public static final int DECODE_MAX = 128;
    

    public static String decode(String encBase64String,String privateKeyString) throws Exception {
        BASE64Decoder base64Decoder = new BASE64Decoder();
        byte[] desEncodeRead = base64Decoder.decodeBuffer(privateKeyString);//
        DerValue d = new DerValue(desEncodeRead);
        RSAPrivateKey privateKey= (RSAPrivateKey) RSAPrivateKeyImpl.parseKey(d);
        Cipher cipher =Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        byte[] src = base64Decoder.decodeBuffer(encBase64String);
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        for(int i=0; i

 

RSA/ECB/PKCS1Padding 算法，加密字节最大117，但不论设置到大，加密后的字节数组大小为128，
解密必须按128个字节一组进行，否则报错，128个字节一组实际上也保证了分段加加密是可逆的，分段
解密后能得到加密前的字节数组