加密用到的JAR包
<!-- https://mvnrepository.com/artifact/org.apache.commons/commons-io --> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-io</artifactId> <version>1.3.2</version> </dependency> <!-- https://mvnrepository.com/artifact/org.apache.directory.studio/org.apache.commons.codec --> <dependency> <groupId>org.apache.directory.studio</groupId> <artifactId>org.apache.commons.codec</artifactId> <version>1.8</version> </dependency>
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.io.IOUtils;
import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.security.*;
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.HashMap;
import java.util.Map;
public class RSAUtils {
public static final String CHARSET = "UTF-8";
public static final String RSA_ALGORITHM = "RSA";
public static Map<String, String> createKeys(int keySize){
//为RSA算法创建一个KeyPairGenerator对象
KeyPairGenerator kpg;
try{
kpg = KeyPairGenerator.getInstance(RSA_ALGORITHM);
}catch(NoSuchAlgorithmException e){
throw new IllegalArgumentException("No such algorithm-->[" + RSA_ALGORITHM + "]");
}
//初始化KeyPairGenerator对象,密钥长度
kpg.initialize(keySize);
//生成密匙对
KeyPair keyPair = kpg.generateKeyPair();
//得到公钥
Key publicKey = keyPair.getPublic();
String publicKeyStr = Base64.encodeBase64URLSafeString(publicKey.getEncoded());
//得到私钥
Key privateKey = keyPair.getPrivate();
String privateKeyStr = Base64.encodeBase64URLSafeString(privateKey.getEncoded());
Map<String, String> keyPairMap = new HashMap<String, String>();
keyPairMap.put("publicKey", publicKeyStr);
keyPairMap.put("privateKey", privateKeyStr);
return keyPairMap;
}
/**
* 得到公钥
* @param publicKey 密钥字符串（经过base64编码）
* @throws Exception
*/
public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
//通过X509编码的Key指令获得公钥对象
KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
return key;
}
/**
* 得到私钥
* @param privateKey 密钥字符串（经过base64编码）
* @throws Exception
*/
public static RSAPrivateKey getPrivateKey(String privateKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
//通过PKCS#8编码的Key指令获得私钥对象
KeyFactory keyFactory = KeyFactory.getInstance(RSA_ALGORITHM);
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));
RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
return key;
}
/**
* 公钥加密
* @param data
* @param publicKey
* @return
*/
public static String publicEncrypt(String data, RSAPublicKey publicKey){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), publicKey.getModulus().bitLength()));
}catch(Exception e){
throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
}
}
/**
* 私钥解密
* @param data
* @param privateKey
* @return
*/
public static String privateDecrypt(String data, RSAPrivateKey privateKey){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, privateKey);
return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), privateKey.getModulus().bitLength()), CHARSET);
}catch(Exception e){
throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
}
}
/**
* 私钥加密
* @param data
* @param privateKey
* @return
*/
public static String privateEncrypt(String data, RSAPrivateKey privateKey){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
return Base64.encodeBase64URLSafeString(rsaSplitCodec(cipher, Cipher.ENCRYPT_MODE, data.getBytes(CHARSET), privateKey.getModulus().bitLength()));
}catch(Exception e){
throw new RuntimeException("加密字符串[" + data + "]时遇到异常", e);
}
}
/**
* 公钥解密
* @param data
* @param publicKey
* @return
*/
public static String publicDecrypt(String data, RSAPublicKey publicKey){
try{
Cipher cipher = Cipher.getInstance(RSA_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, publicKey);
return new String(rsaSplitCodec(cipher, Cipher.DECRYPT_MODE, Base64.decodeBase64(data), publicKey.getModulus().bitLength()), CHARSET);
}catch(Exception e){
throw new RuntimeException("解密字符串[" + data + "]时遇到异常", e);
}
}
private static byte[] rsaSplitCodec(Cipher cipher, int opmode, byte[] datas, int keySize){
int maxBlock = 0;
if(opmode == Cipher.DECRYPT_MODE){
maxBlock = keySize / 8;
}else{
maxBlock = keySize / 8 - 11;
}
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] buff;
int i = 0;
try{
while(datas.length > offSet){
if(datas.length-offSet > maxBlock){
buff = cipher.doFinal(datas, offSet, maxBlock);
}else{
buff = cipher.doFinal(datas, offSet, datas.length-offSet);
}
out.write(buff, 0, buff.length);
i++;
offSet = i * maxBlock;
}
}catch(Exception e){
throw new RuntimeException("加解密阀值为["+maxBlock+"]的数据时发生异常", e);
}
byte[] resultDatas = out.toByteArray();
IOUtils.closeQuietly(out);
return resultDatas;
}
}一般公钥和私钥都是配置在properties文件中，所以，提前把公钥私钥准备好
public class Test1 {
public static void main (String[] args) throws Exception {
Map<String, String> keyMap = RSAUtils.createKeys(1024);
// String publicKey = keyMap.get("publicKey");
String publicKey="MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCIHvSdTGM4SThaSZ9pdsu09wsEyuwRp_w-aSCPajTizykD2DtyxOANaeynYBXibkFtsZ5bujnEwEH5NwqzYdvJUcU-SqriC4wP9uhpdWS7wEAM9kqn9GCT5TN-aqk8RG3X_WwErum-D7obSYm2eqyrGQJsH4WJRU2-IMeUrUUlawIDAQAB";
// String privateKey = keyMap.get("privateKey");
String privateKey = "MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAIge9J1MYzhJOFpJn2l2y7T3CwTK7BGn_D5pII9qNOLPKQPYO3LE4A1p7KdgFeJuQW2xnlu6OcTAQfk3CrNh28lRxT5KquILjA_26Gl1ZLvAQAz2Sqf0YJPlM35qqTxEbdf9bASu6b4PuhtJibZ6rKsZAmwfhYlFTb4gx5StRSVrAgMBAAECgYAmR35G1fp5E64zRcz8nZm_tFF28ZHdjT4UVv__FMD2n4dLO33MUq0nWIhisVS2Lodbz71W0lH4kJB9AwuRUo258KKQp7Rx_PH_LKQgKbB-W4EAyzQKNxDC8JXn0kivNw_EEYPuFc_EErvrRlTvoAbRZNaqO05mK8C30dSPlZA6cQJBAMGvoZ-ZRH3GaYdZNoGrY9nob57QY_LMAltMZijxqu4nwMU6SppzhlqzHQjeyef2NB63-qr_QYfK3B-Ou5oq4DcCQQCz6iUYkL6fFGgyrHDn4VjYJ7dlsJXOJQAy2o9Zr1LjqhX6tyLC9HufzYrZA71qbKjEAZ1noB-mhjHW0sL8tsJtAkEAmKINnjYsUWnQs8bMO3eTIqAXhnH2sdmvab9VKqL37uII-eQr8ndjw4ovMVRQjKnq_OJDegnZ3Gcy_POAR8fOFQJBAIXInc8XivfF9_l-avKyihsp5WEznyHMN8qY5TG-gneSeYeWeL3ZiLf64r2e31Hs_M3LmZ193ys37IWe8alzyT0CQHjp3hCz9EuEn1HcYJrGtm1G7Tduq7RhY8OABhOPTMUL2hkSXKOcvaQk6tbpjR_23HT0rGaFjiRYb1W0RPqXW28";
System.out.println("公钥: \n\r" + publicKey);
System.out.println("私钥： \n\r" + privateKey);
System.out.println("公钥加密——私钥解密");
String str = "站在大明门前守卫的禁卫军，事先没有接到\n" +
"有关的命令，但看到大批盛装的官员来临，也就\n" +
"以为确系举行大典，因而未加询问。进大明门即\n" +
"为皇城。文武百官看到端门午门之前气氛平静，\n" +
"城楼上下也无朝会的迹象，既无几案，站队点名\n" +
"的御史和御前侍卫“大汉将军”也不见踪影，不免\n" +
"心中揣测，互相询问：所谓午朝是否讹传？";
System.out.println("\r明文：\r\n" + str);
System.out.println("\r明文大小：\r\n" + str.getBytes().length);
String encodedData = RSAUtils.publicEncrypt(str, RSAUtils.getPublicKey(publicKey));
System.out.println("密文：\r\n" + encodedData);
String decodedData = RSAUtils.privateDecrypt(encodedData, RSAUtils.getPrivateKey(privateKey));
System.out.println("解密后文字: \r\n" + decodedData);
}
}
原文：https://blog.csdn.net/cz0217/article/details/78426733