android使用AES加密和解密文件实例代码

前言

最近公司需要对本公司的一些下载文件进行加密解密需求，也就尝试去实现下，其实需要借助第三方的jar包：bcprov-jdk15on-155.jar，下载这个可以到网上搜或者下载本人的demo即可，注意：需要加密和解密的key是一致的才可以解密，不然就会解密失败。不多说，直接上代码。

效果图

代码：

实现加密解密逻辑代码

package com.vsoontech.p2p.sample; 

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom; 

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.ShortBufferException; 

/**
 * @author zhou
 * @since 2016/9/26
 */ 

public enum AES {
  INSTANCE;
  private Key key; 

  /**
   * 生成AES对称秘钥
   */
  public String generateKey() throws NoSuchAlgorithmException {
    KeyGenerator keygen = KeyGenerator.getInstance("AES");
    SecureRandom random = new SecureRandom();
    keygen.init(random);
    this.key = keygen.generateKey();
    return "Algorithm Format Encoded:" + key.getAlgorithm() + " - " + key.getFormat() + " - " + new String(key.getEncoded());
  } 

  /**
   * 加密
   */
  public void encrypt(InputStream in) throws InvalidKeyException, ShortBufferException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException, IOException {
    this.crypt(in, null, Cipher.ENCRYPT_MODE);
  } 

  /**
   * 解密
   */
  public String decrypt(InputStream in) throws InvalidKeyException, ShortBufferException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException, IOException {
    return this.crypt(in, Cipher.DECRYPT_MODE);
  } 

  /**
   * 加密
   */
  public void encrypt(InputStream in, OutputStream out) throws InvalidKeyException, ShortBufferException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException, IOException {
    this.crypt(in, out, Cipher.ENCRYPT_MODE);
  } 

  /**
   * 解密
   */
  public void decrypt(InputStream in, OutputStream out) throws InvalidKeyException, ShortBufferException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException, IOException {
    this.crypt(in, out, Cipher.DECRYPT_MODE);
  } 

  /**
   * 实际的加密解密过程
   */
  public void crypt(InputStream in, OutputStream out, int mode) throws IOException, ShortBufferException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(mode, this.key); 

    int blockSize = cipher.getBlockSize();
    int outputSize = cipher.getOutputSize(blockSize);
    byte[] inBytes = new byte[blockSize];
    byte[] outBytes = new byte[outputSize]; 

    int inLength = 0;
    boolean more = true;
    while (more) {
      inLength = in.read(inBytes);
      if (inLength == blockSize) {  //只要输入数据块具有全长度（长度可被8整除），调用update方法
        int outLength = cipher.update(inBytes, 0, blockSize, outBytes);
        if (out != null) out.write(outBytes, 0, outLength);
      } else {
        more = false;
      }
    }
    if (inLength > 0)  //不具有全长度，调用doFinal方法
      outBytes = cipher.doFinal(inBytes, 0, inLength);
    else
      outBytes = cipher.doFinal();
    if (out != null) {
      out.write(outBytes);
      out.flush();
    }
  } 

  /**
   * 实际的加密解密过程
   */
  public String crypt(InputStream in, int mode) throws IOException, ShortBufferException, IllegalBlockSizeException, BadPaddingException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
    Cipher cipher = Cipher.getInstance("AES");
    cipher.init(mode, this.key); 

    int blockSize = cipher.getBlockSize();
    int outputSize = cipher.getOutputSize(blockSize);
    byte[] inBytes = new byte[blockSize];
    byte[] outBytes = new byte[outputSize]; 

    int inLength = 0;
    boolean more = true;
    StringBuilder sb = new StringBuilder();
    while (more) {
      inLength = in.read(inBytes);
      if (inLength == blockSize) {  //只要输入数据块具有全长度（长度可被8整除），调用update方法
        int outLength = cipher.update(inBytes, 0, blockSize, outBytes);
      } else {
        more = false;
      }
    }
    if (inLength > 0)  //不具有全长度，调用doFinal方法
      outBytes = cipher.doFinal(inBytes, 0, inLength);
    else
      outBytes = cipher.doFinal();
    sb.append(new String(outBytes));
    return sb.toString();
  } 

  public void setKey(Key key) {
    this.key = key;
  } 

  public Key getKey() {
    return key;
  }
}

生成秘钥代码

package com.vsoontech.p2p.sample; 

import org.bouncycastle.jce.provider.BouncyCastleProvider; 

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.security.Key;
import java.security.NoSuchAlgorithmException; 

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec; 

/**
 * @author zhou
 * @since 2016/9/26
 */ 

public class AESKeyModel {
  public static final String KEY_ALGORITHM = "AES";
  private static final String DEFAULT_CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding";
  private String srcFile = "", destionFile = ""; 

  /**
   * 初始化密钥
   *
   * @return byte[] 密钥
   * @throws Exception
   */
  public byte[] initSecretKey() {
    //返回生成指定算法的秘密密钥的 KeyGenerator 对象
    KeyGenerator kg = null;
    try {
      kg = KeyGenerator.getInstance(KEY_ALGORITHM);
    } catch (NoSuchAlgorithmException e) {
      e.printStackTrace();
      return new byte[0];
    }
    //初始化此密钥生成器，使其具有确定的密钥大小
    //AES 要求密钥长度为 128
    kg.init(128);
    //生成一个密钥
    SecretKey secretKey = kg.generateKey();
    return secretKey.getEncoded();
  } 

  public void setDestionFile(String destionFile) {
    this.destionFile = destionFile;
  } 

  public void setSrcFile(String srcFile) {
    this.srcFile = srcFile;
  } 

  /**
   * 转换密钥
   *
   * @param key 二进制密钥
   * @return 密钥
   */
  private static Key toKey(byte[] key) {
    //生成密钥
    return new SecretKeySpec(key, KEY_ALGORITHM);
  } 

  /**
   * 加密
   *
   * @param data 待加密数据
   * @param key 密钥
   * @return byte[]  加密数据
   * @throws Exception
   */
  public static byte[] encrypt(byte[] data, Key key) throws Exception {
    return encrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
  } 

  /**
   * 加密
   *
   * @param data 待加密数据
   * @param key 二进制密钥
   * @return byte[]  加密数据
   * @throws Exception
   */
  public static byte[] encrypt(byte[] data, byte[] key) throws Exception {
    return encrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
  } 

  /**
   * 加密
   *
   * @param data      待加密数据
   * @param key       二进制密钥
   * @param cipherAlgorithm 加密算法/工作模式/填充方式
   * @return byte[]  加密数据
   * @throws Exception
   */
  public static byte[] encrypt(byte[] data, byte[] key, String cipherAlgorithm) throws Exception {
    //还原密钥
    Key k = toKey(key);
    return encrypt(data, k, cipherAlgorithm);
  } 

  /**
   * 加密
   *
   * @param data      待加密数据
   * @param key       密钥
   * @param cipherAlgorithm 加密算法/工作模式/填充方式
   * @return byte[]  加密数据
   * @throws Exception
   */
  public static byte[] encrypt(byte[] data, Key key, String cipherAlgorithm) throws Exception {
    //实例化
    Cipher cipher = Cipher.getInstance(cipherAlgorithm);
    //使用密钥初始化，设置为加密模式
    cipher.init(Cipher.ENCRYPT_MODE, key);
    //执行操作
    return cipher.doFinal(data);
  } 

  /**
   * 解密
   *
   * @param data 待解密数据
   * @param key 二进制密钥
   * @return byte[]  解密数据
   * @throws Exception
   */
  public static byte[] decrypt(byte[] data, byte[] key) throws Exception {
    return decrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
  } 

  /**
   * 解密
   *
   * @param data 待解密数据
   * @param key 密钥
   * @return byte[]  解密数据
   * @throws Exception
   */
  public static byte[] decrypt(byte[] data, Key key) throws Exception {
    return decrypt(data, key, DEFAULT_CIPHER_ALGORITHM);
  } 

  /**
   * 解密
   *
   * @param data      待解密数据
   * @param key       二进制密钥
   * @param cipherAlgorithm 加密算法/工作模式/填充方式
   * @return byte[]  解密数据
   * @throws Exception
   */
  public static byte[] decrypt(byte[] data, byte[] key, String cipherAlgorithm) throws Exception {
    //还原密钥
    Key k = toKey(key);
    return decrypt(data, k, cipherAlgorithm);
  } 

  /**
   * 解密
   *
   * @param data      待解密数据
   * @param key       密钥
   * @param cipherAlgorithm 加密算法/工作模式/填充方式
   * @return byte[]  解密数据
   * @throws Exception
   */
  public static byte[] decrypt(byte[] data, Key key, String cipherAlgorithm) throws Exception {
    //实例化
    Cipher cipher = Cipher.getInstance(cipherAlgorithm);
    //使用密钥初始化，设置为解密模式
    cipher.init(Cipher.DECRYPT_MODE, key);
    //执行操作
    return cipher.doFinal(data);
  } 

  public void encryptionFile(Key sessionKey) throws Exception {
    int len = 0;
    byte[] buffer = new byte[1024];
    byte[] cipherbuffer = null; 

    // 使用会话密钥对文件加密。
    Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM, new BouncyCastleProvider());
    IvParameterSpec iv = new IvParameterSpec("0000000000123456".getBytes());
    cipher.init(Cipher.ENCRYPT_MODE, sessionKey, iv); 

    FileInputStream fis = new FileInputStream(new File(srcFile));
    FileOutputStream fos = new FileOutputStream(new File(destionFile)); 

    // 读取原文，加密并写密文到输出文件。
    while ((len = fis.read(buffer)) != -1) {
      cipherbuffer = cipher.update(buffer, 0, len);
      fos.write(cipherbuffer);
      fos.flush();
    }
    cipherbuffer = cipher.doFinal();
    fos.write(cipherbuffer);
    fos.flush(); 

    if (fis != null)
      fis.close();
    if (fos != null)
      fos.close();
  } 

  public void descryptionFile(Key sessionKey) throws Exception {
    int len = 0;
    byte[] buffer = new byte[5 * 1024];
    byte[] plainbuffer = null; 

    Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM, new BouncyCastleProvider());
    IvParameterSpec iv = new IvParameterSpec("0000000000123456".getBytes());
    cipher.init(Cipher.DECRYPT_MODE, sessionKey, iv); 

    FileInputStream fis = new FileInputStream(new File(srcFile));
    FileOutputStream fos = new FileOutputStream(new File(destionFile)); 

    while ((len = fis.read(buffer)) != -1) {
      plainbuffer = cipher.update(buffer, 0, len);
      fos.write(plainbuffer);
      fos.flush();
    } 

    plainbuffer = cipher.doFinal();
    fos.write(plainbuffer);
    fos.flush(); 

    if (fis != null)
      fis.close();
    if (fos != null)
      fos.close();
  }
}

加密逻辑示例代码

/**
   * 加密
   *
   * @param path
   * @param destionFile
   */
  private void aes(String path, String destionFile) {
    try {
      Log.d(TAG, "aes Key: " + AES.INSTANCE.generateKey());
      FileInputStream fis = new FileInputStream(new File(path));
      FileOutputStream fos = new FileOutputStream(new File(destionFile));
      AES.INSTANCE.encrypt(fis, fos);
    } catch (Exception e) {
      Log.d(TAG, "Exception: " + e.toString());
      e.printStackTrace();
    } 

  }

解密逻辑示例代码：

/**
   * AES解密文件
   *
   * @param path 需要解密的文件目录
   */
  private void aesJieMi(String path) {
    File f = new File(path);
    if (!f.exists() || f.isDirectory())
      Toast.makeText(getApplicationContext(), "该文件不合法!", Toast.LENGTH_SHORT).show();
    else {
      String prefix = f.getName().substring(0, f.getName().indexOf('.'));
      String suffix = f.getName().substring(f.getName().indexOf('.'));
      String outjiemiFile = Environment.getExternalStorageDirectory() + File.separator + prefix + "AES_jieMi" + suffix; 

      AESKeyModel model_aes = new AESKeyModel();
      model_aes.setSrcFile(path);
      model_aes.setDestionFile(outjiemiFile); 

      try {
//        model_aes.descryptionFile(key_AES);
        model_aes.descryptionFile(key_aes);
        // TODO: 加密后的文件
        RandomAccessFile raf = new RandomAccessFile(path, "rw");
        Log.d(TAG, "解密后 file length: " + raf.length());
        Log.d(TAG, "解密后 file content: " + raf.readLine());
      } catch (Exception e) {
        e.printStackTrace();
      }
    }
  }

总结：

注意秘钥需要一致。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持我们。