首先了解下，什么是堆成加密，什么是非对称加密？
对称加密：加密与解密的密钥是相同的，加解密速度很快，比如AES
非对称加密：加密与解密的秘钥是不同的，速度较慢，比如RSA
先看代码（先会用在研究）
相关依赖：
<dependency>
<groupId>org.bouncycastle</groupId>
<artifactId>bcprov-jdk15on</artifactId>
<version>1.58</version>
</dependency>
1，RSA工具类：
package cn.wangtao.utils; import org.bouncycastle.jce.provider.BouncyCastleProvider; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import javax.crypto.Cipher; import java.io.ByteArrayOutputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectOutputStream; import java.security.*; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; /** * @ClassName RSAUtils * @Auth 桃子 * @Date 2019-6-25 15:15 * @Version 1.0 * @Description **/ public class RSAUtils { private static final String RSA = "RSA"; // 加密方式
private static final Logger logger= LoggerFactory.getLogger(RSAUtils.class); //获取密钥 public static KeyPair getKey() throws Exception { try { KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(RSA, new BouncyCastleProvider()); keyPairGenerator.initialize(2048); // 初始化密钥长度 KeyPair keyPair = keyPairGenerator.generateKeyPair();// 生成密钥对 return keyPair; } catch (Exception e) { logger.error("获取RSA秘钥对异常",e); throw new Exception("获取RSA秘钥对异常",e); } } //利用公钥进行加密 public static String encryptStr(RSAPublicKey publicKey, String str) throws Exception { try { Cipher cipher = Cipher.getInstance(RSA, new BouncyCastleProvider()); cipher.init(Cipher.ENCRYPT_MODE, publicKey); //加密 byte[] bytes = getBytes(str.getBytes(), cipher); //2进行转换成16进制 String result = CommonUtils.parseByte2HexStr(bytes); return result; } catch (Exception e) { logger.error("使用RSA公钥进行加密异常",e); throw new Exception("使用RSA公钥进行加密异常",e); } } //利用私钥进行解密 public static String decryptStr(RSAPrivateKey privateKey, String str) throws Exception { try { Cipher cipher = Cipher.getInstance(RSA, new BouncyCastleProvider()); cipher.init(Cipher.DECRYPT_MODE, privateKey); // 用密钥初始化此Cipher对象 //16进制转换成2进制 byte[] bytes = CommonUtils.parseHexStr2Byte(str); //解密 byte[] bs = getBytes(bytes, cipher); String content=new String(bs,"utf-8"); return content; } catch (Exception e) { logger.error("使用RSA私钥进行解密异常",e); throw new Exception("使用RSA私钥进行解密异常",e); } } //通过cipher获取字节数组 public static byte[] getBytes(byte[] bytes,Cipher cipher) throws Exception { int blockSize = cipher.getBlockSize(); // 返回块的大小 int j = 0; ByteArrayOutputStream baos = new ByteArrayOutputStream(); while (bytes.length - j * blockSize > 0) { // 将二进制数据分块写入ByteArrayOutputStream中 if(bytes.length-j*blockSize>blockSize){ baos.write(cipher.doFinal(bytes, j * blockSize, blockSize)); }else{ baos.write(cipher.doFinal(bytes, j * blockSize,bytes.length-j*blockSize)); } j++; } baos.close(); byte[] byteArray = baos.toByteArray(); return byteArray; } //保存秘钥对到文件 public void saveRSAKey(String fileName) throws Exception { FileOutputStream fos=null; ObjectOutputStream oos=null; try { KeyPair keyPair = getKey(); fos=new FileOutputStream(fileName); oos=new ObjectOutputStream(fos); //对象序列号 oos.writeObject(keyPair); } catch (Exception e) { logger.error("RSA秘钥对保存到文件异常[{}]",fileName,e); throw new Exception("RSA秘钥对保存到文件异常",e); }finally { if(oos!=null){ try { oos.close(); } catch (IOException e1) { e1.printStackTrace(); } } if(fos!=null){ try { fos.close(); } catch (IOException e1) { e1.printStackTrace(); } } } } }
2，CommonUtils通用工具类：
package cn.wangtao.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
/**
* @ClassName CommonUtils
* @Auth 桃子
* @Date 2019-6-27 12:51
* @Version 1.0
* @Description
**/
public class CommonUtils {
private static final Logger logger= LoggerFactory.getLogger(CommonUtils.class);
//编码方式
public static final String CODE_TYPE = "UTF-8";
//字符补全
private static final String[] consult = new String[]{"0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F","G"};
//关流
public static void closeReaderandWriter(Reader reader, Writer writer){
if(writer!=null){
try {
writer.close();
} catch (IOException e) {
logger.error("关闭输出流失败",e);
}
}
if(reader!=null){
try {
reader.close();
} catch (IOException e) {
logger.error("关闭输出流失败",e);
}
}
}
//将16进制转换为二进制
public static byte[] parseHexStr2Byte(String hexStr) {
if (hexStr.length() < 1)
return null;
byte[] result = new byte[hexStr.length()/2];
for (int i = 0;i< hexStr.length()/2; i++) {
int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
result[i] = (byte) (high * 16 + low);
}
return result;
}
//将二进制转换成16进制
public static String parseByte2HexStr(byte buf[]) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i < buf.length; i++) {
String hex = Integer.toHexString(buf[i] & 0xFF);
if (hex.length() == 1) {
hex = '0' + hex;
}
sb.append(hex.toUpperCase());
}
return sb.toString();
}
//补全字符
public static String completionCodeFor16Bytes(String str) throws Exception {
try{
int num = str.getBytes(CODE_TYPE).length;
int index = num%16;
//进行加密内容补全操作, 加密内容应该为 16字节的倍数, 当不足16*n字节是进行补全, 差一位时 补全16+1位
//补全字符 以 $ 开始,$后一位代表$后补全字符位数,之后全部以0进行补全;
if(index != 0){
StringBuffer sbBuffer = new StringBuffer(str);
if(16-index == 1){
sbBuffer.append("$" + consult[16-1] + addStr(16-1-1));
}else{
sbBuffer.append("$" + consult[16-index-1] + addStr(16-index-1-1));
}
str = sbBuffer.toString();
}
return str;
}catch (Exception e){
logger.error("使用AES加密前补全字符异常",e);
throw new Exception("使用AES加密前补全字符异常",e);
}
}
//追加字符
public static String addStr(int num){
StringBuffer sbBuffer = new StringBuffer("");
for (int i = 0; i < num; i++) {
sbBuffer.append("0");
}
return sbBuffer.toString();
}
//还原字符(进行字符判断)
public static String resumeCodeOf16Bytes(String str) throws Exception{
int indexOf = str.lastIndexOf("$");
if(indexOf == -1){
return str;
}
String trim = str.substring(indexOf+1,indexOf+2).trim();
int num = 0;
for (int i = 0; i < consult.length; i++) {
if(trim.equals(consult[i])){
num = i;
}
}
if(num == 0){
return str;
}
return str.substring(0,indexOf).trim();
}
}
3，AESUtils通用工具类：
package cn.wangtao.utils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.io.*;
import java.security.interfaces.RSAPrivateKey;
import java.util.Map;
/**
* @ClassName AESUtils
* @Auth 桃子
* @Date 2019-6-27 12:05
* @Version 1.0
* @Description
**/
public class AESUtils {
private static final Logger logger= LoggerFactory.getLogger(AESUtils.class);
//填充类型
public static final String AES_TYPE = "AES/ECB/PKCS5Padding";
private static final String AES = "AES"; // 加密方式
public static final String DES_TYPE = "DES/ECB/PKCS5Padding";
private static final String DES = "DES"; // 加密方式
private final String defaultDesKey="11112222";//8位
//对字符串加密
public static String encryptStr(String content,String aesKey) throws Exception {
try {
SecretKeySpec key = new SecretKeySpec(aesKey.getBytes(),AES );
Cipher cipher = Cipher.getInstance(AES_TYPE);
cipher.init(Cipher.ENCRYPT_MODE, key);
//字符补全
String content16Str = CommonUtils.completionCodeFor16Bytes(content);
byte[] encryptedData = cipher.doFinal(content16Str.getBytes(CommonUtils.CODE_TYPE));
//2进制转换成16进制
String hexStr = CommonUtils.parseByte2HexStr(encryptedData);
return hexStr;
} catch (Exception e) {
logger.error("使用AES对字符串加密异常",e);
throw new Exception("使用AES对字符串加密异常",e);
}
}
//对字符串解密
public static String decryptStr(String content,String aesKey) throws Exception {
try {
//16进制转换成2进制
byte[] bytes = CommonUtils.parseHexStr2Byte(content);
SecretKeySpec key = new SecretKeySpec(
aesKey.getBytes(), AES);
Cipher cipher = Cipher.getInstance(AES_TYPE);
cipher.init(Cipher.DECRYPT_MODE, key);
byte[] decryptedData = cipher.doFinal(bytes);
String result=new String(decryptedData, CommonUtils.CODE_TYPE);
//还原字符
String orgResult = CommonUtils.resumeCodeOf16Bytes(result);
return orgResult;
} catch (Exception e) {
logger.error("使用AES对字符串解密异常",e);
throw new Exception("使用AES对字符串解密异常",e);
}
}
//对文件加密
public static File encryptFile(File orgFile, File encryptFile, Map<String,Object> context) throws Exception {
logger.info("使用AES对文件加密开始，源文件地址[{}]加密后文件地址[{}]",orgFile.getPath(),encryptFile.getPath());
BufferedReader br=null;
BufferedWriter bw=null;
try{
//获取AESKEY ，如果没有为默认
String aesKey = (String) context.get(Dirt.AES_KEY);
br=new BufferedReader(new FileReader(orgFile));
bw=(BufferedWriter)context.get(Dirt.BUFFEREDWRITER);
if(null==bw){
bw=new BufferedWriter(new FileWriter(encryptFile));
}
String len=null;
while (null!=(len=br.readLine())){
String encrypt= encryptStr(len,aesKey);
bw.write(encrypt);
bw.newLine();
bw.flush();
}
logger.info("使用AES对文件加密结束，源文件地址[{}]加密后文件地址[{}]",orgFile.getPath(),encryptFile.getPath());
return encryptFile;
}catch (Exception e){
logger.error("使用AES对文件加密异常,源文件地址[{}]加密后文件地址[{}]",orgFile.getPath(),encryptFile.getPath(),e);
throw new Exception("使用AES对文件加密异常",e);
}finally {
CommonUtils.closeReaderandWriter(br,bw);
}
}
//对文本解密，返回解密文件后的文件
public static File decryptFile(File decryptfile, File encryptFile,Map<String,Object> context) throws Exception {
logger.info("使用AES对文件解密开始，源加密文件地址[{}]解密后文件地址[{}]",encryptFile.getPath(),decryptfile.getPath());
BufferedReader br=null;
BufferedWriter bw=null;
try{
if(decryptfile.exists()){
decryptfile.delete();
}
//边读边加密边写
br=new BufferedReader(new FileReader(encryptFile));
bw=new BufferedWriter(new FileWriter(decryptfile));
String len=null;
String aesKey=null;
//判断是否加密
RSAPrivateKey privateKey= (RSAPrivateKey) context.get(Dirt.RSAPRIVATEKEY);
if(null!=privateKey){
StringBuffer sb=new StringBuffer();
while ((len=br.readLine())!=null){
sb.append(len);
if(len.equals("\n")||len.equals("")||len.equals("\r\n")||len.equals("\r")){
aesKey=RSAUtils.decryptStr(privateKey,sb.toString());
break;
}
}
}
if(null==aesKey){
aesKey=(String) context.get(Dirt.AES_KEY);
}
logger.info("aesKey[{}]",aesKey);
if(aesKey!=null){
while ((len=br.readLine())!=null){
String decrypt= decryptStr(len,aesKey);
bw.write(decrypt);
bw.flush();
bw.newLine();
}
}
logger.info("使用AES对文件解密结束，源加密文件地址[{}]解密后文件地址[{}]",encryptFile.getPath(),decryptfile.getPath());
return decryptfile;
}catch (Exception e){
logger.error("使用AES对文件解密异常,源加密文件地址[{}]解密后文件地址[{}]",encryptFile.getPath(),decryptfile.getPath(),e);
throw new Exception("使用AES对文件解密异常",e);
}finally {
CommonUtils.closeReaderandWriter(br,bw);
}
}
}
4，Dirt常量
package cn.wangtao.utils;
import java.security.interfaces.RSAPublicKey;
/**
* @ClassName Dirt
* @Auth 桃子
* @Date 2019-6-27 14:20
* @Version 1.0
* @Description
**/
public class Dirt {
public static final String UPLOADFILEURL="uploadFileUrl";
public static final String AES_KEY="aesKey";
public static final String RSAPUBLICKEY="rsaPublicKey";
public static final String RSAPRIVATEKEY="rsaPrivateKey";
public final static String RETURNCODE="returnCode";
public final static String RETURNMSG="returnMsg";
public final static String FILENAME="fileName";
public final static String ORGFILENAME="orgFileName";
public final static String ENCRYPTFILE="encryptFile";
public static final String BUFFEREDWRITER="bufferedWriter"; //是为了在原始文件中进行补充加密
//返回码
public final static String SUCCESSCODE="000000";
public final static String FAILEDCODE="999999";
//加密文件所放的目录
public final static String BASELOCALDIR="XXX"; //基本目录路径
public final static String ENCRYPTLOCALDIR="encrypt"; //加密文件目录
}
AES的介绍
详情请参考：https://blog.csdn.net/qq_28205153/article/details/55798628
RSA的介绍
详情请参考：https://www.cnblogs.com/jiftle/p/7903762.html
