非对称加密分段处理加密大量数据

基于RSA非对称加密,属于轻量型加密,加密数据的大小有严格限制,我们可以通过对分段加密方式,实现对大量数据的非对称加密,本文在参考非对称的加密的资料基础之上,实现了大数据的非对称加密,因此少量数据于大量数据都可以实现加密处理,如果仅想实现这个非对称加密功能代码可直接使用。

代码实现:

package com.company.test;


import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Arrays;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

import sun.misc.BASE64Decoder;

public class RSAEncrypt {

    //一次能够加密的最大数据长度
	private static final Integer MAX_LENGTH_STR=128;
	
    //这里可以通过调用密钥对进行生成公钥;
	private static final String DEFAULT_PUBLIC_KEY= 
		"MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQChDzcjw/rWgFwnxunbKp7/4e8w" + "\r" +
		"/UmXx2jk6qEEn69t6N2R1i/LmcyDT1xr/T2AHGOiXNQ5V8W4iCaaeNawi7aJaRht" + "\r" +
		"Vx1uOH/2U378fscEESEG8XDqll0GCfB1/TjKI2aitVSzXOtRs8kYgGU78f7VmDNg" + "\r" +
		"XIlk3gdhnzh+uoEQywIDAQAB" + "\r";
	
    //这里可以通过调用密钥对进行生成私钥;
	private static final String DEFAULT_PRIVATE_KEY=
		"MIICdQIBADANBgkqhkiG9w0BAQEFAASCAl8wggJbAgEAAoGBAKEPNyPD+taAXCfG" + "\r" +
		"6dsqnv/h7zD9SZfHaOTqoQSfr23o3ZHWL8uZzINPXGv9PYAcY6Jc1DlXxbiIJpp4" + "\r" +
		"1rCLtolpGG1XHW44f/ZTfvx+xwQRIQbxcOqWXQYJ8HX9OMojZqK1VLNc61GzyRiA" + "\r" +
		"ZTvx/tWYM2BciWTeB2GfOH66gRDLAgMBAAECgYBp4qTvoJKynuT3SbDJY/XwaEtm" + "\r" +
		"u768SF9P0GlXrtwYuDWjAVue0VhBI9WxMWZTaVafkcP8hxX4QZqPh84td0zjcq3j" + "\r" +
		"DLOegAFJkIorGzq5FyK7ydBoU1TLjFV459c8dTZMTu+LgsOTD11/V/Jr4NJxIudo" + "\r" +
		"MBQ3c4cHmOoYv4uzkQJBANR+7Fc3e6oZgqTOesqPSPqljbsdF9E4x4eDFuOecCkJ" + "\r" +
		"DvVLOOoAzvtHfAiUp+H3fk4hXRpALiNBEHiIdhIuX2UCQQDCCHiPHFd4gC58yyCM" + "\r" +
		"6Leqkmoa+6YpfRb3oxykLBXcWx7DtbX+ayKy5OQmnkEG+MW8XB8wAdiUl0/tb6cQ" + "\r" +
		"FaRvAkBhvP94Hk0DMDinFVHlWYJ3xy4pongSA8vCyMj+aSGtvjzjFnZXK4gIjBjA" + "\r" +
		"2Z9ekDfIOBBawqp2DLdGuX2VXz8BAkByMuIh+KBSv76cnEDwLhfLQJlKgEnvqTvX" + "\r" +
		"TB0TUw8avlaBAXW34/5sI+NUB1hmbgyTK/T/IFcEPXpBWLGO+e3pAkAGWLpnH0Zh" + "\r" +
		"Fae7oAqkMAd3xCNY6ec180tAe57hZ6kS+SYLKwb4gGzYaCxc22vMtYksXHtUeamo" + "\r" +
		"1NMLzI2ZfUoX" + "\r";
 
	/**
	 * 私钥
	 */
	private RSAPrivateKey privateKey;
 
	/**
	 * 公钥
	 */
	private RSAPublicKey publicKey;
	
	/**
	 * 字节数据转字符串专用集合
	 */
	private static final char[] HEX_CHAR= {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
	
 
	/**
	 * 获取私钥
	 * @return 当前的私钥对象
	 */
	public RSAPrivateKey getPrivateKey() {
		return privateKey;
	}
 
	/**
	 * 获取公钥
	 * @return 当前的公钥对象
	 */
	public RSAPublicKey getPublicKey() {
		return publicKey;
	}
 
	/**
	 * 随机生成密钥对
	 */
	public void genKeyPair(){
		KeyPairGenerator keyPairGen= null;
		try {
			keyPairGen= KeyPairGenerator.getInstance("RSA");
		} catch (NoSuchAlgorithmException e) {
			e.printStackTrace();
		}
		keyPairGen.initialize(1024, new SecureRandom());
		KeyPair keyPair= keyPairGen.generateKeyPair();
		this.privateKey= (RSAPrivateKey) keyPair.getPrivate();
		this.publicKey= (RSAPublicKey) keyPair.getPublic();
	}

 
	/**
	 * 从字符串中加载公钥
	 * @param publicKeyStr 公钥数据字符串
	 * @throws Exception 加载公钥时产生的异常
	 */
	public void loadPublicKey(String publicKeyStr) throws Exception{
		try {
			BASE64Decoder base64Decoder= new BASE64Decoder();
			byte[] buffer= base64Decoder.decodeBuffer(publicKeyStr);
			KeyFactory keyFactory= KeyFactory.getInstance("RSA");
			X509EncodedKeySpec keySpec= new X509EncodedKeySpec(buffer);
			this.publicKey= (RSAPublicKey) keyFactory.generatePublic(keySpec);
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此算法");
		} catch (InvalidKeySpecException e) {
			throw new Exception("公钥非法");
		} catch (IOException e) {
			throw new Exception("公钥数据内容读取错误");
		} catch (NullPointerException e) {
			throw new Exception("公钥数据为空");
		}
	}

	/**
	 * 从字符串中加载私钥
	 * @param privateKeyStr
	 * @throws Exception
	 */
	public void loadPrivateKey(String privateKeyStr) throws Exception{
		try {
			BASE64Decoder base64Decoder= new BASE64Decoder();
			byte[] buffer= base64Decoder.decodeBuffer(privateKeyStr);
			PKCS8EncodedKeySpec keySpec= new PKCS8EncodedKeySpec(buffer);
			KeyFactory keyFactory= KeyFactory.getInstance("RSA");
			this.privateKey= (RSAPrivateKey) keyFactory.generatePrivate(keySpec);
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此算法");
		} catch (InvalidKeySpecException e) {
			throw new Exception("私钥非法");
		} catch (IOException e) {
			throw new Exception("私钥数据内容读取错误");
		} catch (NullPointerException e) {
			throw new Exception("私钥数据为空");
		}
	}
 
	/**
	 * 加密过程
	 * @param publicKey 公钥
	 * @param plainTextData 明文数据
	 * @return
	 * @throws Exception 加密过程中的异常信息
	 */
	public byte[] encrypt(RSAPublicKey publicKey, byte[] plainTextData) throws Exception{
		if(publicKey== null){
			throw new Exception("加密公钥为空, 请设置");
		}
		Cipher cipher= null;
		try {
			cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
			cipher.init(Cipher.ENCRYPT_MODE, publicKey);
			byte[] output= cipher.doFinal(plainTextData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此加密算法");
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
			return null;
		}catch (InvalidKeyException e) {
			throw new Exception("加密公钥非法,请检查");
		} catch (IllegalBlockSizeException e) {
			throw new Exception("明文长度非法");
		} catch (BadPaddingException e) {
			throw new Exception("明文数据已损坏");
		}
	}
 
	/**
	 * 解密过程
	 * @param privateKey 私钥
	 * @param cipherData 密文数据
	 * @return 明文
	 * @throws Exception 解密过程中的异常信息
	 */
	public byte[] decrypt(RSAPrivateKey privateKey, byte[] cipherData) throws Exception{
		if (privateKey== null){
			throw new Exception("解密私钥为空, 请设置");
		}
		Cipher cipher= null;
		try {
			cipher= Cipher.getInstance("RSA", new BouncyCastleProvider());
			cipher.init(Cipher.DECRYPT_MODE, privateKey);
			byte[] output= cipher.doFinal(cipherData);
			return output;
		} catch (NoSuchAlgorithmException e) {
			throw new Exception("无此解密算法");
		} catch (NoSuchPaddingException e) {
			e.printStackTrace();
			return null;
		}catch (InvalidKeyException e) {
			throw new Exception("解密私钥非法,请检查");
		} catch (IllegalBlockSizeException e) {
			throw new Exception("密文长度非法");
		} catch (BadPaddingException e) {
			throw new Exception("密文数据已损坏");
		}		
	}
 
	
	/**
	 * 字节数据转十六进制字符串
	 * @param data 输入数据
	 * @return 十六进制内容
	 */
	public static String byteArrayToString(byte[] data){
		StringBuilder stringBuilder= new StringBuilder();
		for (int i=0; i<data.length; i++){
			//取出字节的高四位 作为索引得到相应的十六进制标识符 注意无符号右移
			stringBuilder.append(HEX_CHAR[(data[i] & 0xf0)>>> 4]);
			//取出字节的低四位 作为索引得到相应的十六进制标识符
			stringBuilder.append(HEX_CHAR[(data[i] & 0x0f)]);
			if (i<data.length-1){
				stringBuilder.append(' ');
			}
		}
		return stringBuilder.toString();
	}
 
 
	public static void main(String[] args){

		RSAEncrypt rsaEncrypt= new RSAEncrypt();
		//加载公钥
		try {
			rsaEncrypt.loadPublicKey(RSAEncrypt.DEFAULT_PUBLIC_KEY);
			System.out.println("加载公钥成功");
		} catch (Exception e) {
			System.err.println(e.getMessage());
			System.err.println("加载公钥失败");
		}
		//加载私钥
		try {
			rsaEncrypt.loadPrivateKey(RSAEncrypt.DEFAULT_PRIVATE_KEY);
			System.out.println("加载私钥成功");
		} catch (Exception e) {
			System.err.println(e.getMessage());
			System.err.println("加载私钥失败");
		}
		//测试字符串
		String encryptStr= "TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTestttttttttttttttttttttttttttttttttttttttttttttttyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy";
		System.out.println("输入的字符串长度"+encryptStr.length());

		int all = encryptStr.length();
		//把String分成多个子字符串数组
		//子字符串长度
		int start=0;
		int strsLen;
		int i = all /RSAEncrypt.MAX_LENGTH_STR ;//有bug这行(bug已经修复)
		strsLen = i != 0 ? i + 1 : 1;
		String[] strs=new String[strsLen];
		for (int j = 0; j < strsLen; j++) {
			if (j<strsLen-1){
				strs[j]=encryptStr.substring(start,start+=RSAEncrypt.MAX_LENGTH_STR);//顾首不顾尾
			}else {
				strs[j]=encryptStr.substring(start,all);
			}
		}
		System.out.println(Arrays.toString(strs));

		//定义StringBuffer进行数组拼接
		StringBuffer cipherText = new StringBuffer();
		StringBuffer lightText = new StringBuffer();
		//遍历分段的字符
		Arrays.stream(strs).forEach(str -> {
			try {
				//加密
				byte[] cipher = rsaEncrypt.encrypt(rsaEncrypt.getPublicKey(), str.getBytes());
				cipherText.append(RSAEncrypt.byteArrayToString(cipher));
				//解密
				byte[] plainText = rsaEncrypt.decrypt(rsaEncrypt.getPrivateKey(), cipher);
				lightText.append(new String(plainText));
			} catch (Exception e) {
				System.err.println(e.getMessage());
			}
		}
		);
		System.out.println("返回的密文:"+cipherText);
		System.out.println("拼接回来的明文"+lightText.toString());
		System.out.println(encryptStr.equals(lightText.toString()));//与原来的明文比较
	}
}

PS:这里是通过读取代码中字符串公私钥的方式进行实现的,还可以将公私存储在文件中,利用流的方式进行读取。

可参考:

RSA介绍：RSA算法_百度百科

OpenSSL介绍：openssl_百度百科

链接：https://blog.youkuaiyun.com/chaijunkun/article/details/7275632

密钥对生成：http://www.howforge.com/how-to-generate-key-pair-using-openssl

私钥编码格式转换：http://shuany.iteye.com/blog/730910