Rsa加密类

阅读原文时间：2023年07月13日阅读：1

需要导入Base64.jar包

import java.io.ByteArrayOutputStream;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;

import Decoder.BASE64Decoder;
import Decoder.BASE64Encoder;

public class RSACrypt {

/**
* 文件读取缓冲区大小
*/
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 new BASE64Decoder().decodeBuffer(base64);
}

/**
*

* 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 BASE64Encoder().encode(bytes);
}

/**
* 加密算法RSA
*/
// public static final String KEY_ALGORITHM = "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 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 keyMap = new HashMap(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}

/**
*

* 生成密钥对(公钥和私钥) *

*
* @return
* @throws Exception
*/
public static Map genKeyPair(String seed) throws Exception {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
keyPairGen.initialize(1024);
// SecureRandom secrand = new SecureRandom();
// secrand.setSeed(seed.getBytes()); // 初始化随机产生器
// keyPairGen.initialize(1024, secrand);
KeyPair keyPair = keyPairGen.generateKeyPair();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
Map keyMap = new HashMap(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 = 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 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 = 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(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 = 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 cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");

  cipher.init(Cipher.DECRYPT\_MODE, privateK);  
  int inputLen = encryptedData.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 > MAX\_DECRYPT\_BLOCK) {  
        cache = cipher.doFinal(encryptedData, offSet, MAX\_DECRYPT\_BLOCK);  
     } else {  
        cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);  
     }  
     out.write(cache, 0, cache.length);  
     i++;  
     offSet = i \* MAX\_DECRYPT\_BLOCK;  
  }  
  byte\[\] decryptedData = out.toByteArray();  
  out.close();  
  return decryptedData;

}

/**
*

* 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 = 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 cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");  
  cipher.init(Cipher.DECRYPT\_MODE, publicK);  
  int inputLen = encryptedData.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 > MAX\_DECRYPT\_BLOCK) {  
        cache = cipher.doFinal(encryptedData, offSet, MAX\_DECRYPT\_BLOCK);  
     } else {  
        cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);  
     }  
     out.write(cache, 0, cache.length);  
     i++;  
     offSet = i \* MAX\_DECRYPT\_BLOCK;  
  }  
  byte\[\] decryptedData = out.toByteArray();  
  out.close();  
  return decryptedData;

}

/**
*

* 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 = decode(publicKey);
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
Key publicK = keyFactory.generatePublic(x509KeySpec);
// 对数据加密
// Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

  Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");

  cipher.init(Cipher.ENCRYPT\_MODE, publicK);  
  int inputLen = data.length;  
  ByteArrayOutputStream out = new ByteArrayOutputStream();  
  int offSet = 0;  
  byte\[\] cache;  
  int i = 0;  
  // 对数据分段加密  
  while (inputLen - offSet > 0) {  
     if (inputLen - offSet > MAX\_ENCRYPT\_BLOCK) {  
        cache = cipher.doFinal(data, offSet, MAX\_ENCRYPT\_BLOCK);  
     } else {  
        cache = cipher.doFinal(data, offSet, inputLen - offSet);  
     }  
     out.write(cache, 0, cache.length);  
     i++;  
     offSet = i \* MAX\_ENCRYPT\_BLOCK;  
  }  
  byte\[\] encryptedData = out.toByteArray();  
  out.close();  
  return encryptedData;

}

/**
*

* 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 = 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 cipher = Cipher.getInstance("RSA/ECB/PKCS1PADDING");
cipher.init(Cipher.ENCRYPT_MODE, privateK);
int inputLen = data.length;
ByteArrayOutputStream out = new ByteArrayOutputStream();
int offSet = 0;
byte[] cache;
int i = 0;
// 对数据分段加密
while (inputLen - offSet > 0) {
if (inputLen - offSet > MAX_ENCRYPT_BLOCK) {
cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);
} else {
cache = cipher.doFinal(data, offSet, inputLen - offSet);
}
out.write(cache, 0, cache.length);
i++;
offSet = i * MAX_ENCRYPT_BLOCK;
}
byte[] encryptedData = out.toByteArray();
out.close();
return encryptedData;
}

/**
*

* 获取私钥 *

*
* @param keyMap
* 密钥对
* @return
* @throws Exception
*/
public static String getPrivateKey(Map keyMap) throws Exception {
Key key = (Key) keyMap.get(PRIVATE_KEY);
return encode(key.getEncoded());
}

/**
*

* 获取公钥 *

*
* @param keyMap
* 密钥对
* @return
* @throws Exception
*/
public static String getPublicKey(Map keyMap) throws Exception {
Key key = (Key) keyMap.get(PUBLIC_KEY);
return encode(key.getEncoded());
}

}
________________________________________
public class Rsademo {
public static void main(String[] args) {
try {
String privateKey = "MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAKB8GunT65dDzvV4" + "VD6UA9+lGEjIgEtyEVtrp3rEhBRmvOZ1sromkybrAF4ByodHh1BmgBLdImMqMzH2"
+ "vgwc3ioOqiaODqHNPpqa/jeSrdNE/hJSKQqPXi+qVaIg6tOi84GnirHOrwkVxR45" + "kQgj4lH7qnIaMhooaIModIsDTGs7AgMBAAECgYEAg/Jlwlhtu9mRgDslsKnLoYZA"
+ "uB65dM5dPPf/JC4MliV+LFEa2Hg8xmOy0pfQZ3dE5rLPnDLaQgQBQZQn3xehBE/N" + "2YdzLEH1Dpw1eOJY30Qf/Rp6jUaTwY5gQCxSDt24CXpDjzo09dvaR4uHhRNZX1KB"
+ "XNco+PiM7ujFaSrhuBkCQQDQC3d2OhQB4vAaxaPzwqQv6lAFWCR8Osy5jyY/KlVF" + "kd/VzXp2uWACgFm6UXmUwyLfrSpFl013E5SjOsdgpXYNAkEAxXoqed1TYAHHS63N"
+ "oIQlMz/ygHiMtkFeoD8HgKYw5TzYCpqlM++2O1VcbTLjQtnwctIe3B3xF7eOZ1Si" + "53KcZwJAdPaNYhWC3BCnJpYI9+ls/1c/R9HnKUSxhn05Zne5WxSJAB22hPrxRFa+"
+ "m2Zk8ULH33LuehN3RMPoY+CO6QH9HQJBAK9+JrtP7iU2z2a42TEZ3nlSDe8PsnTR" + "WQdtm/w/NNqznIan8cJa+AZ4kH/WplIlneJcSuJwlW3vSNUZSQAIQWcCQHBsB41q"
+ "WyyPcRBjMCR6YO4Iih/07kZJDAqHrdnhea+aNF+MPuShqIGlcDEbdeS1XxUp8gSm" + "diXEh5aJvpTfSEY=";

     String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCgfBrp0+uXQ871eFQ+lAPfpRhI" + "yIBLchFba6d6xIQUZrzmdbK6JpMm6wBeAcqHR4dQZoAS3SJjKjMx9r4MHN4qDqom"  
           + "jg6hzT6amv43kq3TRP4SUikKj14vqlWiIOrTovOBp4qxzq8JFcUeOZEII+JR+6py" + "GjIaKGiDKHSLA0xrOwIDAQAB";

     System.out.println("privateKey=" + privateKey);  
     System.err.println("私钥加密——公钥解密");  
     String source = "hyx\_912\_74571852356eb1dd4902f66c9c7ad103e8285d010d27488b";  
     System.out.println("原文字：\\r\\n" + source);  
     byte\[\] data = source.getBytes();  
     // byte\[\] encodedData = RSACrypt.encryptByPrivateKey(data, privateKey);  
     byte\[\] encodedData = RSACrypt.encryptByPublicKey(data, publicKey);  
     String enBaseDate = RSACrypt.encode(encodedData);  
     System.out.println("加密后：\\r\\n" + enBaseDate);  
     // byte\[\] decryptByPublicKey = RSACrypt.decryptByPublicKey(encodedData, publicKey);  
     byte\[\] decryptByPublicKey = RSACrypt.decryptByPrivateKey(encodedData, privateKey);  
     System.out.println("解密后：\\r\\n" + new String(decryptByPublicKey));  
  } catch (Exception e) {  
     e.printStackTrace();  
  }

}
}

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