公钥加密，私钥解密
前端：密文RSA公钥加密，得到base64编码的加密文本，jsencrypt.min.js
var publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDQZX1Kg0I59W4KwMq0VsZRHp5GE5me474JefjiDK/ewrftAxeKMAnjAfAe2mEb6ZYMz2UKDF2fDKhi3Ctqkqa04HbbuDVu8 fU7A436RUGouyge MK0hjpLlUKvDL dknUq4twpArpWjYtXgikQI1nh8XPTNH/nRSy50kQ3ComRwIDAQAB"; var encrypt = new JSEncrypt(); encrypt.setPublicKey(publicKey); mmVal = encrypt.encrypt("123456"); 后端：
- 生成公钥和私钥，Map<String, Object> map = RSAUtils.genKeyPair();
- 收到机密密文，把base64密码解码为二进制数组，然后解密
- 二进制数组转化为密文
1、base64编码工具类
** * BASE64编码解码工具包 * * @author Created by zqc on 2018/11/02. */ public class BaseUtils {
/** * 读取缓冲区大小的文件 */ private static final int CACHE_SIZE = 1024; /** * BASE64字符串解码为二进制数据 * * @param base64 * @return * @throws Exception */ public static byte[] decode(String base64) throws Exception {
return Base64.getDecoder().decode(base64); // return Base64.decode(base64.getBytes()); } /** * 二进制数据编码为BASE64字符串 * * @param bytes * @return * @throws Exception */ public static String encode(byte[] bytes) throws Exception {
// return new StringBase64.encode(bytes));
return Base64.getEncoder().encodeToString(bytes);
}
/** * 将文件编码为BASE64字符串 大文件慎用，可能会导致内存溢出 * * @param filePath 文件绝对路径 * @return * @throws Exception */
public static String encodeFile(String filePath) throws Exception {
byte[] bytes = fileToByte(filePath);
return encode(bytes);
}
/** * <p> * BASE64字符串转回文件 * * @param filePath 文件绝对路径 * @param base64 编码字符串 * @throws Exception */
public static void decodeToFile(String filePath, String base64) throws Exception {
byte[] bytes = decode(base64);
byteArrayToFile(bytes, filePath);
}
/** * 文件转换为二进制数组 * * @param filePath 文件路径 * @return * @throws Exception */
public static byte[] fileToByte(String filePath) throws Exception {
byte[] data = new byte[0];
File file = new File(filePath);
if (file.exists()) {
FileInputStream in = new FileInputStream(file);
ByteArrayOutputStream out = new ByteArrayOutputStream(2048);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
data = out.toByteArray();
}
return data;
}
/** * 二进制数据写文件bytes 二进制数据 * * @param filePath 文件生成目录 */
public static void byteArrayToFile(byte[] bytes, String filePath) throws Exception {
InputStream in = new ByteArrayInputStream(bytes);
File destFile = new File(filePath);
if (!destFile.getParentFile().exists()) {
destFile.getParentFile().mkdirs();
}
destFile.createNewFile();
OutputStream out = new FileOutputStream(destFile);
byte[] cache = new byte[CACHE_SIZE];
int nRead = 0;
while ((nRead = in.read(cache)) != -1) {
out.write(cache, 0, nRead);
out.flush();
}
out.close();
in.close();
}
}
2、RSA加密解密工具类
/** * <p> * RSA公钥/私钥/签名工具包 * </p> * <p> * 罗纳德・李维斯特（Ron [R]ivest）、阿迪・萨莫尔（Adi [S]hamir）和伦纳德・阿德曼（Leonard [A]dleman） * </p> * <p> * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式<br/> * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，<br/> * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全 * </p> * * @author Created by zqc on 2018/11/02. */ public class RSAUtils { /** * 加密算法RSA */ public static final String KEY_ALGORITHM = "RSA"; /** * 签名算法 */ public static final String SIGNATURE_ALGORITHM = "MD5withRSA"; /** * 获取公钥的key */ private static final String PUBLIC_KEY = "RSAPublicKey"; /** * 获取私钥的key */ private static final String PRIVATE_KEY = "RSAPrivateKey"; /** * RSA最大加密明文大小 */ private static final int MAX_ENCRYPT_BLOCK = 117; /** * RSA最大解密密文大小 */ private static final int MAX_DECRYPT_BLOCK = 128; /** * 生成密钥对(公钥和私钥) * * @return * @throws Exception */ public static Map<String, Object> genKeyPair() throws Exception { KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM); keyPairGen.initialize(1024); KeyPair keyPair = keyPairGen.generateKeyPair(); RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); Map<String, Object> keyMap = new HashMap<String, Object>(2); keyMap.put(PUBLIC_KEY, publicKey); keyMap.put(PRIVATE_KEY, privateKey); return keyMap; } /** * 用私钥对信息生成数字签名 * * @param data 已加密数据 * @param privateKey 私钥(BASE64编码) * @return * @throws Exception */ public static String sign(byte[] data, String privateKey) throws Exception { byte[] keyBytes = BaseUtils.decode(privateKey); PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec); Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initSign(privateK); signature.update(data); return BaseUtils.encode(signature.sign()); } /** * 校验数字签名 * * @param data 已加密数据 * @param publicKey 公钥(BASE64编码) * @param sign 数字签名 * @return * @throws Exception */ public static boolean verify(byte[] data, String publicKey, String sign) throws Exception { byte[] keyBytes = BaseUtils.decode(publicKey); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); PublicKey publicK = keyFactory.generatePublic(keySpec); Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM); signature.initVerify(publicK); signature.update(data); return signature.verify(BaseUtils.decode(sign)); } /** * 私钥解密 * * @param encryptedData 已加密数据 * @param privateKey 私钥(BASE64编码) * @return * @throws Exception */ public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey) throws Exception { byte[] keyBytes = BaseUtils.decode(privateKey); PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key privateK = keyFactory.generatePrivate(pkcs8KeySpec); Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.DECRYPT_MODE, privateK); return getByteArray(encryptedData, cipher, MAX_DECRYPT_BLOCK); } private static byte[] getByteArray(byte[] data, Cipher cipher, int maxBlockSize) throws IllegalBlockSizeException, BadPaddingException, IOException { int inputLen = data.length; ByteArrayOutputStream out = new ByteArrayOutputStream(); int offSet = 0; byte[] cache; int i = 0; // 对数据分段解密 while (inputLen - offSet > 0) { if (inputLen - offSet > maxBlockSize) { cache = cipher.doFinal(data, offSet, maxBlockSize); } else { cache = cipher.doFinal(data, offSet, inputLen - offSet); } out.write(cache, 0, cache.length); i++; offSet = i * maxBlockSize; } byte[] endeData = out.toByteArray(); out.close(); return endeData; } /** * 公钥解密 * * @param encryptedData 已加密数据 * @param publicKey 公钥(BASE64编码) * @return * @throws Exception */ public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey) throws Exception { byte[] keyBytes = BaseUtils.decode(publicKey); X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key publicK = keyFactory.generatePublic(x509KeySpec); Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.DECRYPT_MODE, publicK); return getByteArray(encryptedData, cipher, MAX_DECRYPT_BLOCK); } /** * 公钥加密 * * @param data 源数据 * @param publicKey 公钥(BASE64编码) * @return * @throws Exception */ public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception { byte[] keyBytes = BaseUtils.decode(publicKey); X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key publicK = keyFactory.generatePublic(x509KeySpec); Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.ENCRYPT_MODE, publicK); return getByteArray(data, cipher, MAX_ENCRYPT_BLOCK); } /** * 私钥加密 * * @param data 源数据 * @param privateKey 私钥(BASE64编码) * @return * @throws Exception */ public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception { byte[] keyBytes = BaseUtils.decode(privateKey); PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM); Key privateK = keyFactory.generatePrivate(pkcs8KeySpec); Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm()); cipher.init(Cipher.ENCRYPT_MODE, privateK); return getByteArray(data, cipher, MAX_ENCRYPT_BLOCK); } /** * 获取私钥 * * @param keyMap 密钥对 * @return * @throws Exception */ public static String getPrivateKey(Map<String, Object> keyMap) throws Exception { Key key = (Key) keyMap.get(PRIVATE_KEY); return BaseUtils.encode(key.getEncoded()); } /** * 获取公钥 * * @param keyMap 密钥对 * @return * @throws Exception */ public static String getPublicKey(Map<String, Object> keyMap) throws Exception { Key key = (Key) keyMap.get(PUBLIC_KEY); return BaseUtils.encode(key.getEncoded()); } }
3、解密测试
public class Base64Test {
public static void main(String[] args) throws Exception {
//生成公钥私钥，生成一次就可以，公钥不变，私钥会变
/*Map<String, Object> map = RSAUtils.genKeyPair(); System.out.println(map); String publicKey = RSAUtils.getPublicKey(map); String privateKey = RSAUtils.getPrivateKey(map); */
String publicKey="MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCbj3V1MC7zFGnyPWDcv/55nQRklXB1KyZ7mpglV2SiCoDcWqArAEUjfp5iHQT59Wfyg+56fBnKV0nuvBEXRICytaZuGFiQYeDqEkuR5mkSIEnvcld+TgHAbeXRAIry8LE59efeJcyqQoCDG2sA8pMgEqVNhfP/hDb5+uH0QAvLWQIDAQAB";
String privateKey="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";
String encode="LE60PdTwuMo4rH4vnC53vEVyVez3J/1uXYRozVJWFnyXcOoZHvJSU2/5RlHIi/ws600hbzDJsmP/w19hVL+u8NbI2AXtJ0jnLMcsAOVLN/ryL98oHkdVTO1aQfthNIRx28NgVnPYwfdodxbHLym3wLXCi6JbmzBr2wuyBC+9cME=";
byte[] decrypt = RSAUtils.decryptByPrivateKey(BaseUtils.decode(encode), privateKey);//把base64密码解码为二进制数组，再解密，得到密文二进制数组
String encode1 = new String(decrypt);//二进制数组转换成密文
System.out.println("解密："+encode1);
}
}
参考博客：