Android 客户端RSA加密的实现方法

Android 客户端RSA加密的实现方法

针对java后端进行的RSA加密，android客户端进行解密，结果是部分乱码的问题：

注意两点，编码问题和客户端使用的算法问题

即：都使用UTF-8编码，Base64使用一致，另外，使用下面的代码在后端和移动端解密只有一点不同：

移动端使用

Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");

后端使用

Cipher cipher = Cipher.getInstance("RSA");

其他地方都不需要改动

package rsa;

import android.util.Base64;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

//import org.apache.commons.codec.binary.Base64;

/** *//**
* <p>
* BASE64编码解码工具包
* </p>
* @author IceWee
* @date 2012-5-19
* @version 1.0
*/
public class Base64Utils {

/** *//**
  * 文件读取缓冲区大小
  */
 private static final int CACHE_SIZE = 1024;

/** *//**
  * <p>
  * BASE64字符串解码为二进制数据
  * </p>
  *
  * @param base64
  * @return
  * @throws Exception
  */
 public static byte[] decode(String base64) throws Exception {
   return Base64.decode(base64.getBytes(), Base64.DEFAULT);
 }
 /** *//**
  * <p>
  * 二进制数据编码为BASE64字符串
  * </p>
  *
  * @param bytes
  * @return
  * @throws Exception
  */
 public static String encode(byte[] bytes) throws Exception {
   return new String(Base64.encode(bytes, Base64.DEFAULT));
 }
 /**
  *
  * @param str
  * @return
  * @throws Exception
  */
 public static String encode(String str) throws Exception {
   byte[] bytes = str.getBytes("utf-8");
   return encode(bytes);
 }
 /** *//**
  * <p>
  * 将文件编码为BASE64字符串
  * </p>
  * <p>
  * 大文件慎用，可能会导致内存溢出
  * </p>
  *
  * @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
  * </p>
  *
  * @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);
 }

/** *//**
  * <p>
  * 文件转换为二进制数组
  * </p>
  *
  * @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;
 }

/** *//**
  * <p>
  * 二进制数据写文件
  * </p>
  *
  * @param 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();
 }

}

package rsa;

import android.util.Base64;

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;

/**
* <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 IceWee
* @date 2012-4-26
* @version 1.0
*/
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;

/**
  * <p>
  * 生成密钥对(公钥和私钥)
  * </p>
  *
  * @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;
 }

/**
  * <p>
  * 用私钥对信息生成数字签名
  * </p>
  *
  * @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 = Base64.decode(privateKey,0);

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 Base64.encodeToString(signature.sign(), 0);
 }

/**
  * <p>
  * 校验数字签名
  * </p>
  *
  * @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 = Base64.decode(publicKey,0);
   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(Base64.decode(sign,0));
 }

/**
  * <P>
  * 私钥解密
  * </p>
  *
  * @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 = Base64.decode(privateKey, 0);
   PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
   KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
   Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);
   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;
 }

/**
  * <p>
  * 公钥解密
  * </p>
  *
  * @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 = Base64.decode(publicKey,0);
   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);
   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;
 }

/**
  * <p>
  * 公钥加密
  * </p>
  *
  * @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 = Base64.decode(publicKey,0);
   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.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;
 }

/**
  * <p>
  * 私钥加密
  * </p>
  *
  * @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 = Base64.decode(privateKey,0);
   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);
   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;
 }

/**
  * <p>
  * 获取私钥
  * </p>
  *
  * @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 Base64.encodeToString(key.getEncoded(),0);
 }

/**
  * <p>
  * 获取公钥
  * </p>
  *
  * @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 Base64.encodeToString(key.getEncoded(), 0);
 }

}

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来源：http://www.cnblogs.com/qianyukun/p/4998150.html