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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