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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
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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();}}}}}
/*** @ClassName RSAUtils* @Version 1.0* @Description RSA工具类**/
public class RSAUtils {private static final String RSA = "RSA";public static final String MD5WITHRSA="MD5withRSA";public static final String SHA1WITHRSA="SHA1withRSA";private static Logger logger= LoggerFactory.getLogger(RSAUtils.class);/*** @desc 读取秘钥文本内容* @createTime 2019年7月2日 下午5:20:38* @param keyFile 秘钥文件* @return 秘钥文本内容* @throws Exception*/private static String initKeyByFile(File keyFile) throws Exception {if(keyFile.exists() && keyFile.isFile()) {BufferedReader bufferedReader = null;try {bufferedReader = new BufferedReader(new FileReader(keyFile));StringBuilder stringBuilder = new StringBuilder();String line = null;while ((line = bufferedReader.readLine()) != null) {if (line.length() == 0 || line.charAt(0) == '-') {continue;}stringBuilder.append(line).append(System.getProperty("line.separator"));}return stringBuilder.toString();}catch (Exception e) {logger.error("读取秘钥文本内容异常",e);throw new Exception("读取秘钥文本内容异常",e);}finally {CommonUtils.closeReaderandWriter(bufferedReader, null);}}return null;}/*** @desc 获取公钥* @author Liuweian* @createTime 2019年7月2日 下午5:19:34* @param pubKeyFileName 公钥文件地址* @return PublicKey* @throws Exception*/public static PublicKey getPublicKeyByFile(File pubKeyFile) throws Exception {String keyContent = initKeyByFile(pubKeyFile);byte[] keyByte = Base64.decode(keyContent);KeyFactory kf = KeyFactory.getInstance(RSA);X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyByte);return kf.generatePublic(keySpec);}/*** @desc 获取私钥* @createTime 2019年7月2日 下午5:19:16* @param priKeyFileName 私钥文件地址* @return PrivateKey* @throws Exception*/public static PrivateKey getPrivateKeyByFile(File priKeyFile) throws Exception {String keyContent = initKeyByFile(priKeyFile);byte[] keyByte = Base64.decode(keyContent);KeyFactory kf = KeyFactory.getInstance(RSA);PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyByte);return kf.generatePrivate(keySpec);}/*** @desc 使用RSA中的私钥对数据签名* @createTime 2019年7月2日 下午5:24:30* @param privateKey 秘钥对中的私钥* @param data 待加签字节数组* @param signType 加签类型* @return 加签后的签名* @throws Exception*/public static String sign(byte[] data, PrivateKey privateKey, String signType) throws Exception {Signature signature = Signature.getInstance(signType);signature.initSign(privateKey);signature.update(data);byte[] signByte = signature.sign();//Base64加密return new String(Base64.encode(signByte));}/*** @desc 使用RSA中的公钥对签名验签* @createTime 2019年7月2日 下午5:24:30* @param data 待验签字节数组* @param sign 签名* @param publicKey 秘钥对中的公钥* @param signType 加签类型* @return 验签是否成功* @throws Exception*/public static boolean verify(byte[] data, byte[] sign, PublicKey publicKey, String signType) {try {Signature signature = Signature.getInstance(signType);signature.initVerify(publicKey);signature.update(data);//Base64解密byte[] keyByte = Base64.decode(sign);return signature.verify(keyByte);} catch (Exception e) {logger.error("验签出现异常", e);return false;}}/*** @desc 使用RSA中的私钥对数据签名 加签方式 MD5withRSA* @createTime 2019年7月2日 下午5:24:30* @param privateKey 秘钥对中的私钥* @param data 待加签字节数组* @return 加签后的签名* @throws Exception*/public static String signMD5withRSA(byte[] data, PrivateKey privateKey) throws Exception {return sign(data, privateKey, MD5WITHRSA);}/*** @desc 使用RSA中的公钥对签名验签 验签方式 MD5withRSA* @createTime 2019年7月2日 下午5:24:30* @param sign 签名* @param publicKey 秘钥对中的公钥* @param signType 加签类型* @return 验签是否成功，失败则异常抛出* @throws Exception*/public static void verifyMD5withRSA(byte[] data, byte[] sign, PublicKey publicKey) throws Exception {if(!verify(data, sign, publicKey, MD5WITHRSA)) {throw new Exception("验签失败");}}/*** @desc 通过cipher获取字节数组 分块* @createTime 2019年7月2日 下午5:21:33* @param data 待加密的字节数组* @param cipher* @return* @throws Exception*/public static byte[] getBytes(byte[] data, Cipher cipher) throws Exception {int blockSize = cipher.getBlockSize(); // 返回块的大小int j = 0;ByteArrayOutputStream baos = new ByteArrayOutputStream();while (data.length - j * blockSize > 0) { // 将二进制数据分块写入ByteArrayOutputStream中if(data.length - j * blockSize > blockSize) {baos.write(cipher.doFinal(data, j * blockSize, blockSize));}else{baos.write(cipher.doFinal(data, j * blockSize, data.length - j * blockSize));}j++;}baos.close();byte[] byteArray = baos.toByteArray();return byteArray;}/*** @desc 利用公钥进行 加密* @createTime 2019年7月2日 下午5:24:30* @param key 密钥对的一个* @param data 待加密字节数组* @return 密文* @throws Exception*/public static String encrypt(Key key, byte[] data) throws Exception {try {Cipher cipher = Cipher.getInstance(RSA, new BouncyCastleProvider());cipher.init(Cipher.ENCRYPT_MODE, key);//加密byte[] bytes = getBytes(data, cipher);//2进行转换成16进制String result = CommonUtils.parseByte2HexStr(bytes);return new String(Base64.encode(result.getBytes(CommonUtils.CODE_TYPE)));} 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);}}/*** @desc 利用私钥进行 解密* @createTime 2019年7月2日 下午5:23:10* @param key 密钥对的一个* @param data 待解密的字节数组* @return 明文* @throws Exception*/public static String decrypt(Key key, byte[] data) throws Exception {try {Cipher cipher = Cipher.getInstance(RSA, new BouncyCastleProvider());cipher.init(Cipher.DECRYPT_MODE, key); // 用密钥初始化此Cipher对象//16进制转换成2进制byte[] bytes = CommonUtils.parseHexStr2Byte(Base64.decode(data));//解密byte[] bs = getBytes(bytes, cipher);String content=new String(bs,CommonUtils.CODE_TYPE);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);}}}
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);}}
}
/*** @ClassName AESUtils* @Version 1.0* @Description AES工具类**/
public class AESUtils {private static final Logger logger = LoggerFactory.getLogger(AESUtils.class);/** 加密方式 */public static final String AES = "AES";public static final String AES_Type = "AES/ECB/PKCS5Padding";/*** @desc 随机生成AES加密秘钥* @createTime 2019年7月2日 下午5:36:00* @return 随机的AES的秘钥串 16位* @throws Exception*/public static String getAesKey() {Random random = new Random();String result = "";for(int i = 0; i< 16; i++){String charOrNum = random.nextInt(2) % 2 == 0 ? "char" : "num";// 输出字母还是数字if( "char".equalsIgnoreCase(charOrNum) ) {// 输出是大写字母还是小写字母// int temp = random.nextInt(2) % 2 == 0 ? 65 : 97;result += (char)(random.nextInt(26) + 65);} else {result += String.valueOf(random.nextInt(10));}}return result;}/*** @desc AES加密操作* @createTime 2019年7月2日 下午5:30:33* @param data 待加密字节数组* @param aesKey 秘钥串* @return 密文* @throws Exception*/public static String encrypt(byte[] data, String aesKey) throws Exception {try {SecretKeySpec key = new SecretKeySpec(aesKey.getBytes(CommonUtils.CODE_TYPE), AES);Cipher cipher = Cipher.getInstance(AES); cipher.init(Cipher.ENCRYPT_MODE, key);byte[] encryptedData = cipher.doFinal(data);//2进制转换成16进制并返回密文String result = CommonUtils.parseByte2HexStr(encryptedData);return new String(Base64.encode(result.getBytes(CommonUtils.CODE_TYPE)));} 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);}}/*** @desc AES解密操作* @createTime 2019年7月2日 下午5:31:37* @param data 待解密字节数组* @param aesKey 秘钥串* @return 明文* @throws Exception*/public static String decrypt(byte[] data, String aesKey) throws Exception {try {// 16进制转换成2进制byte[] bytes = CommonUtils.parseHexStr2Byte(Base64.decode(data));SecretKeySpec key = new SecretKeySpec(aesKey.getBytes(CommonUtils.CODE_TYPE), AES);Cipher cipher = Cipher.getInstance(AES);cipher.init(Cipher.DECRYPT_MODE, key);//执行解密byte[] decryptedData = cipher.doFinal(bytes);//还原字符并返回return new String(decryptedData, CommonUtils.CODE_TYPE);} 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);}}}
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}
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AES的介绍
详情请参考：https://blog.csdn.net/qq_28205153/article/details/55798628
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RSA的介绍
详情请参考：https://www.cnblogs.com/jiftle/p/7903762.html
