java_AES加密解密文件以及字符串

捣鼓了两个星期的加密解密文件夹，一开始是用异或，后来觉得太简单换成了AES，结果一堆bug，上网查了很多，现在将这个最终的版本记录下来。已经在android 5.1系统上测试过，是可以的。

 /**     * 初始化 AES Cipher     * @param sKey     * @param cipherMode     * @return     */    public static Cipher initAESCipher (String sKey, int cipherMode) throws Exception {        //创建Key gen        KeyGenerator keyGenerator = null;        Cipher cipher = null;            keyGenerator = KeyGenerator.getInstance("AES");            SecureRandom sr = SecureRandom.getInstance( "SHA1PRNG" ,"Crypto");            sr.setSeed(sKey.getBytes("UTF-8"));            keyGenerator.init(128,sr);            SecretKey secretKey = keyGenerator.generateKey();            byte[] codeFormat = secretKey.getEncoded();            SecretKeySpec key = new SecretKeySpec(codeFormat, "AES");            cipher = Cipher.getInstance("AES");            //初始化            cipher.init(cipherMode, key);        return cipher;    }

 /**     * 对文件进行AES加密     * @param sourceFile     * @param fileType     * @param sKey     * @return     */    public static File encryptFile(File sourceFile,String fileType, String sKey) throws Exception {        //新建临时加密文件        File encrypfile = null;        InputStream inputStream = null;        OutputStream outputStream = null;            inputStream = new FileInputStream(sourceFile);            encrypfile = new File(fileType);            outputStream = new FileOutputStream(encrypfile);            Cipher cipher = initAESCipher(sKey,Cipher.ENCRYPT_MODE);            //以加密流写入文件            CipherInputStream cipherInputStream = new CipherInputStream(inputStream, cipher);            byte[] cache = new byte[1024];            int nRead = 0;            while ((nRead = cipherInputStream.read(cache)) != -1) {                outputStream.write(cache, 0, nRead);                outputStream.flush();            }            cipherInputStream.close();            sourceFile.delete();                inputStream.close();                outputStream.close();        Log.d("MainActivity", "加密成功");        return encrypfile;    }

/**     * AES方式解密文件     * @param sourceFile     * @return     */    public static File decryptFile(File sourceFile,String fileType,String sKey) throws Exception {        File decryptFile = null;        InputStream inputStream = null;        OutputStream outputStream = null;            decryptFile = new File(fileType);;            Cipher cipher = initAESCipher(sKey,Cipher.DECRYPT_MODE);            inputStream = new FileInputStream(sourceFile);            outputStream = new FileOutputStream(decryptFile);            CipherOutputStream cipherOutputStream = new CipherOutputStream(outputStream, cipher);            byte [] buffer = new byte [1024];            int r;            while ((r = inputStream.read(buffer)) >= 0) {                cipherOutputStream.write(buffer, 0, r);            }            cipherOutputStream.close();            sourceFile.delete();                inputStream.close();                outputStream.close();        Log.d("MainActivity", "解密成功" );        return decryptFile;    }

如果要加密解密文件夹，只需要遍历进行加密解密即可：

 public static void encryptFolder(String strPath){       File dir = new File(strPath);        File[] files = dir.listFiles();        if (files != null){            for (int i=0; i<files.length;i++){                String fileName = files[i].getName();                if (files[i].isDirectory()){                    encryptFolder(files[i].getAbsolutePath());                }else if(fileName.contains(".lock")){                    //表明该文件已经加密过了，不需要再次加密                    continue;                }else{                    File file = new File(files[i].getAbsolutePath());                    try {                        encryptFile(file,files[i].getAbsolutePath()+".lock", constants.CryptConstant.PRIVATE_AES_KEY);                    } catch (Exception e) {                        e.printStackTrace();                        Log.d("MainActivity","加密出错"+e.getMessage());                    }                }            }        }    }    public static void decryptFolder(String strPath){      File dir = new File(strPath);        File[] files = dir.listFiles();        if (files != null){            for (int i=0; i<files.length;i++){                String fileName = files[i].getName();                if (files[i].isDirectory()){                    decryptFolder(files[i].getAbsolutePath());                }else {                    //只有是加密文件才进行解密                    if (files[i].getAbsolutePath().contains(".lock")){                          File file = new File(files[i].getAbsolutePath());                    try {                        decryptFile(file,files[i].getAbsolutePath().replace(".lock",""), constants.CryptConstant.PRIVATE_AES_KEY);                    } catch (Exception e) {                        e.printStackTrace();                        Log.d("MainActivity", "解密出错" + e.getMessage());                    }                    }                }            }        }    }

加密解密字符串的代码如下：

  /**     * 生成指定字符串的密钥     * @param secret        要生成密钥的字符串     * @return secretKey    生成后的密钥     * @throws GeneralSecurityException     */    private static Key getKey(String secret) throws GeneralSecurityException {        KeyGenerator kgen = KeyGenerator.getInstance(type);        try {            SecureRandom sr = SecureRandom.getInstance( "SHA1PRNG" ,"Crypto");            sr.setSeed(secret.getBytes("UTF-8"));            kgen.init(128,sr);        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        }        SecretKey secretKey = kgen.generateKey();        return secretKey;    }

 public static String encryString(String privateKey,String content){        Key key = null;        try {            key = getKey(privateKey);            Cipher cipher = Cipher.getInstance(type + "/ECB/PKCS5Padding");            cipher.init(Cipher.ENCRYPT_MODE, key);            byte[] byteContent = content.getBytes("UTF-8");            byte[] result=cipher.doFinal(byteContent);            String s = Base64.encodeToString(result, Base64.DEFAULT);            return s;        } catch (GeneralSecurityException e) {            e.printStackTrace();        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        }        return null;    }    public static String decryptString(String privateKey,String content){        Key key = null;        try {            key = getKey(privateKey);            Cipher cipher = Cipher.getInstance(type + "/ECB/PKCS5Padding");            cipher.init(Cipher.DECRYPT_MODE, key);            byte[] decodeValue = Base64.decode(content, Base64.DEFAULT);            byte[] result=cipher.doFinal(decodeValue);            return new String(result,"UTF-8");        } catch (GeneralSecurityException e) {            e.printStackTrace();        } catch (UnsupportedEncodingException e) {            e.printStackTrace();        }        return null;    }