SHA256withRSA 完美工具类 RSAUtils，包含：
1、签名
2、验签
3、公钥加密》私钥解密
4、私钥加密》公钥解密
代码：RSAUtils.java
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.KeyStore;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
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.Enumeration;
import java.util.HashMap;
import java.util.Map;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.lang3.ArrayUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* SHA256withRSA
*
* @author 单红宇
* @date 2019年7月18日
*
*/
public class RSAUtils {
private static final Logger logger = LoggerFactory.getLogger(RSAUtils.class);
// MAX_DECRYPT_BLOCK应等于密钥长度/8（1byte=8bit），所以当密钥位数为2048时，最大解密长度应为256.
// 128 对应 1024，256对应2048
private static final int KEYSIZE = 2048;
// 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;
// 不仅可以使用DSA算法，同样也可以使用RSA算法做数字签名
private static final String KEY_ALGORITHM = "RSA";
private static final String SIGNATURE_ALGORITHM = "SHA256withRSA";
public static final String DEFAULT_SEED = "$%^*%^()(ED47d784sde78"; // 默认种子
public static final String PUBLIC_KEY = "PublicKey";
public static final String PRIVATE_KEY = "PrivateKey";
/**
*
* 生成密钥
*
* @param seed 种子
*
* @return 密钥对象
* @throws Exception
*
*/
public static Map<String, Key> initKey(String seed) throws Exception {
logger.info("生成密钥");
KeyPairGenerator keygen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
SecureRandom secureRandom = new SecureRandom();
// 如果指定seed，那么secureRandom结果是一样的，所以生成的公私钥也永远不会变
// secureRandom.setSeed(seed.getBytes());
// Modulus size must range from 512 to 1024 and be a multiple of 64
keygen.initialize(KEYSIZE, secureRandom);
KeyPair keys = keygen.genKeyPair();
PrivateKey privateKey = keys.getPrivate();
PublicKey publicKey = keys.getPublic();
Map<String, Key> map = new HashMap<>(2);
map.put(PUBLIC_KEY, publicKey);
map.put(PRIVATE_KEY, privateKey);
return map;
}
/**
*
* 生成默认密钥
*
*
* @return 密钥对象
* @throws Exception
*
*/
public static Map<String, Key> initKey() throws Exception {
return initKey(DEFAULT_SEED);
}
/**
*
* 取得私钥
*
* @param keyMap
*
* @return
* @throws Exception
*
*/
public static String getPrivateKey(Map<String, Key> keyMap) throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);
return encryptBASE64(key.getEncoded()); // base64加密私钥
}
/**
*
* 取得公钥
*
* @param keyMap
*
* @return
* @throws Exception
*
*/
public static String getPublicKey(Map<String, Key> keyMap) throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return encryptBASE64(key.getEncoded()); // base64加密公钥
}
/**
*
* 用私钥对信息进行数字签名
*
* @param data 加密数据
*
* @param privateKey 私钥-base64加密的
*
* @return
*
* @throws Exception
*
*/
public static String signByPrivateKey(byte[] data, String privateKey) throws Exception {
logger.info("用私钥对信息进行数字签名");
byte[] keyBytes = decryptBASE64(privateKey);
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory factory = KeyFactory.getInstance(KEY_ALGORITHM);
PrivateKey priKey = factory.generatePrivate(keySpec);// 生成私钥
// 用私钥对信息进行数字签名
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initSign(priKey);
signature.update(data);
return encryptBASE64(signature.sign());
}
/**
*
* BASE64Encoder 加密
*
* @param data 要加密的数据
*
* @return 加密后的字符串
*
*/
private static String encryptBASE64(byte[] data) {
// BASE64Encoder encoder = new BASE64Encoder();
// String encode = encoder.encode(data);
// return encode;
return new String(Base64.encodeBase64(data));
}
private static byte[] decryptBASE64(String data) {
// BASE64Decoder 每76个字符换行
// BASE64Decoder decoder = new BASE64Decoder();
// byte[] buffer = decoder.decodeBuffer(data);
// return buffer;
// codec 的 Base64 不换行
return Base64.decodeBase64(data);
}
public static boolean verifyByPublicKey(byte[] data, String publicKey, String sign) throws Exception {
byte[] keyBytes = decryptBASE64(publicKey);
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
signature.initVerify(pubKey);
signature.update(data);
return signature.verify(decryptBASE64(sign)); // 验证签名
}
/**
* RSA公钥加密
*
* @param str 加密字符串
* @param publicKey 公钥
* @return 密文
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
* @throws NoSuchPaddingException
* @throws InvalidKeyException
* @throws UnsupportedEncodingException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws Exception 加密过程中的异常信息
*/
public static String encryptByPublicKey(String str, String publicKey)
throws InvalidKeySpecException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException {
// base64编码的公钥
byte[] keyBytes = decryptBASE64(publicKey);
RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance(KEY_ALGORITHM)
.generatePublic(new X509EncodedKeySpec(keyBytes));
// RSA加密
Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] data = str.getBytes("UTF-8");
// 加密时超过117字节就报错。为此采用分段加密的办法来加密
byte[] enBytes = null;
for (int i = 0; i < data.length; i += MAX_ENCRYPT_BLOCK) {
// 注意要使用2的倍数，否则会出现加密后的内容再解密时为乱码
byte[] doFinal = cipher.doFinal(ArrayUtils.subarray(data, i, i + MAX_ENCRYPT_BLOCK));
enBytes = ArrayUtils.addAll(enBytes, doFinal);
}
String outStr = encryptBASE64(enBytes);
return outStr;
}
/**
* RSA私钥加密
*
* @param str 加密字符串
* @param privateKey 公钥
* @return 密文
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
* @throws NoSuchPaddingException
* @throws InvalidKeyException
* @throws UnsupportedEncodingException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws Exception 加密过程中的异常信息
*/
public static String encryptByPrivateKey(String str, String privateKey)
throws InvalidKeySpecException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException,
IllegalBlockSizeException, BadPaddingException, UnsupportedEncodingException {
// base64编码的公钥
byte[] keyBytes = decryptBASE64(privateKey);
RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance(KEY_ALGORITHM)
.generatePrivate(new PKCS8EncodedKeySpec(keyBytes));
// RSA加密
Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
cipher.init(Cipher.ENCRYPT_MODE, priKey);
byte[] data = str.getBytes("UTF-8");
// 加密时超过117字节就报错。为此采用分段加密的办法来加密
byte[] enBytes = null;
for (int i = 0; i < data.length; i += MAX_ENCRYPT_BLOCK) {
// 注意要使用2的倍数，否则会出现加密后的内容再解密时为乱码
byte[] doFinal = cipher.doFinal(ArrayUtils.subarray(data, i, i + MAX_ENCRYPT_BLOCK));
enBytes = ArrayUtils.addAll(enBytes, doFinal);
}
String outStr = encryptBASE64(enBytes);
return outStr;
}
/**
* 读取公钥
*
* @param publicKeyPath
* @return
*/
public static PublicKey readPublic(String publicKeyPath) {
if (publicKeyPath != null) {
try (FileInputStream bais = new FileInputStream(publicKeyPath)) {
CertificateFactory certificatefactory = CertificateFactory.getInstance("X.509");
X509Certificate cert = (X509Certificate) certificatefactory.generateCertificate(bais);
return cert.getPublicKey();
} catch (CertificateException e) {
logger.error(e.getMessage(), e);
} catch (FileNotFoundException e) {
logger.error(e.getMessage(), e);
} catch (IOException e) {
logger.error(e.getMessage(), e);
}
}
return null;
}
/**
* 读取私钥
*
* @param path
* @return
*/
public static PrivateKey readPrivate(String privateKeyPath, String privateKeyPwd) {
if (privateKeyPath == null || privateKeyPwd == null) {
return null;
}
try (InputStream stream = new FileInputStream(new File(privateKeyPath));) {
// 获取JKS 服务器私有证书的私钥，取得标准的JKS的 KeyStore实例
KeyStore store = KeyStore.getInstance("JKS");// JKS，二进制格式，同时包含证书和私钥，一般有密码保护；PKCS12，二进制格式，同时包含证书和私钥，一般有密码保护。
// jks文件密码，根据实际情况修改
store.load(stream, privateKeyPwd.toCharArray());
// 获取jks证书别名
Enumeration<String> en = store.aliases();
String pName = null;
while (en.hasMoreElements()) {
String n = (String) en.nextElement();
if (store.isKeyEntry(n)) {
pName = n;
}
}
// 获取证书的私钥
PrivateKey key = (PrivateKey) store.getKey(pName, privateKeyPwd.toCharArray());
return key;
} catch (Exception e) {
logger.error(e.getMessage(), e);
}
return null;
}
/**
* RSA私钥解密
*
* @param encryStr 加密字符串
* @param privateKey 私钥
* @return 铭文
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
* @throws NoSuchPaddingException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws InvalidKeyException
* @throws Exception 解密过程中的异常信息
*/
public static String decryptByPrivateKey(String encryStr, String privateKey)
throws InvalidKeySpecException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException,
BadPaddingException, InvalidKeyException {
// base64编码的私钥
byte[] decoded = decryptBASE64(privateKey);
RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance(KEY_ALGORITHM)
.generatePrivate(new PKCS8EncodedKeySpec(decoded));
// RSA解密
Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, priKey);
// 64位解码加密后的字符串
byte[] data = decryptBASE64(encryStr);
// 解密时超过128字节报错。为此采用分段解密的办法来解密
StringBuilder sb = new StringBuilder();
for (int i = 0; i < data.length; i += MAX_DECRYPT_BLOCK) {
byte[] doFinal = cipher.doFinal(ArrayUtils.subarray(data, i, i + MAX_DECRYPT_BLOCK));
sb.append(new String(doFinal));
}
return sb.toString();
}
/**
* RSA公钥解密
*
* @param encryStr 加密字符串
* @param privateKey 私钥
* @return 铭文
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
* @throws NoSuchPaddingException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws InvalidKeyException
* @throws Exception 解密过程中的异常信息
*/
public static String decryptByPublicKey(String encryStr, String publicKey)
throws InvalidKeySpecException, NoSuchAlgorithmException, NoSuchPaddingException, IllegalBlockSizeException,
BadPaddingException, InvalidKeyException {
// base64编码的私钥
byte[] decoded = decryptBASE64(publicKey);
RSAPublicKey priKey = (RSAPublicKey) KeyFactory.getInstance(KEY_ALGORITHM)
.generatePublic(new X509EncodedKeySpec(decoded));
// RSA解密
Cipher cipher = Cipher.getInstance(KEY_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, priKey);
// 64位解码加密后的字符串
byte[] data = decryptBASE64(encryStr);
// 解密时超过128字节报错。为此采用分段解密的办法来解密
StringBuilder sb = new StringBuilder();
for (int i = 0; i < data.length; i += MAX_DECRYPT_BLOCK) {
byte[] doFinal = cipher.doFinal(ArrayUtils.subarray(data, i, i + MAX_DECRYPT_BLOCK));
sb.append(new String(doFinal));
}
return sb.toString();
}
/**
* main方法测试 第一种用法：公钥加密，私钥解密。---用于加解密 第二种用法：私钥签名，公钥验签。---用于签名
*
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
String ss = "hello";
byte[] data = ss.getBytes();
Map<String, Key> keyMap = initKey();// 构建密钥
PublicKey publicKey = (PublicKey) keyMap.get(PUBLIC_KEY);
PrivateKey privateKey = (PrivateKey) keyMap.get(PRIVATE_KEY);
logger.info("私钥format：{}", privateKey.getFormat());
logger.info("公钥format：{}", publicKey.getFormat());
logger.info("私钥string：{}", getPrivateKey(keyMap));
logger.info("公钥string：{}", getPublicKey(keyMap));
// 产生签名
String sign = signByPrivateKey(data, getPrivateKey(keyMap));
logger.info("签名sign={}", sign);
// 验证签名
boolean verify1 = verifyByPublicKey(ss.getBytes(), getPublicKey(keyMap), sign);
logger.info("经验证数据和签名匹配：{} ", verify1);
boolean verify = verifyByPublicKey(data, getPublicKey(keyMap), sign);
logger.error("经验证数据和签名匹配：{} ", verify);
// logger.info("数字签名为"+sign);
String s = "单红宇测试，e8986ae53e76e7514ebc7e8a42e81e6cea5b6280fb5d3259d5f0a46f9f6e090c";
String encryStr = encryptByPublicKey(s, getPublicKey(keyMap));
logger.info("字符串 {} 的公钥加密结果为：{}", s, encryStr);
String decryStr = decryptByPrivateKey(encryStr, getPrivateKey(keyMap));
logger.info("私钥解密结果为：{}", decryStr);
logger.info("========================================================================================");
String s2 = "单红宇测试222，e8986ae53e76e7514ebc7e8a42e81e6cea5b6280fb5d3259d5f0a46f9f6e090c";
String encryStr2 = encryptByPrivateKey(s, getPrivateKey(keyMap));
logger.info("字符串 {} 的私钥加密结果为：{}", s2, encryStr2);
String decryStr2 = decryptByPublicKey(encryStr2, getPublicKey(keyMap));
logger.info("公钥解密结果为：{}", decryStr2);
}
}
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