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。