Android使用Facebook Conceal进行文件或文本内容的加密解密

一.对于Facebook  Conceal的介绍我就不多说了，网上很多，这里我主要说一下用法。

1.在 moudle 的 build.gradle 里添加

compile 'com.facebook.conceal:conceal:2.0.1@aar'

2.在项目的Application里或首个Activity里初始化Conceal，推荐在Application里初始化具体代码如下：

SoLoader.init(this, false);//第一个参数为context上下文环境

3.Conceal的加密解密是对字节数组byte[]以及数据流inputstream，outputstream等等进行处理，只是简单的对文本内容加密，解密的话，操作字节数组即可。

//先获取一个Crypto 加密对象

KeyChain keyChain = new SharedPrefsBackedKeyChain(this, CryptoConfig.KEY_256);

Crypto crypto = AndroidConceal.get().createDefaultCrypto(keyChain);

String s = "我爱中国";//需加密的字符串
byte[] plainText = s.getBytes();//转换为字节数组
Log.e("tag","加密前=="+plainText);
byte[] cipherText = crypto.encrypt(plainText, Entity.create("mytext"));//对字节数组加密
Log.e("tag","加密后=="+cipherText);

//在需要解密的地方

byte[] cipher = getIntent().getByteArrayExtra("cipherText");//新页面接收传递过来的加密后数组

byte[] plainText = crypto.decrypt(cipher, Entity.create("mytext"));//解密，得到原来的字节数组

String s = new String(cipher);//将字节数组转回字符串

注意：加密解密中Entity.create("mytext")这个参数必须一致

二.文件加密

File file = new File(Environment.getExternalStorageDirectory(),"MyTest");//
if(!file.exists()){
    file.mkdir();//创建MyTest文件夹
}
Log.e("tag","file="+file.exists());
File txtfile = new File(file,"aaaaa.txt");//自己往该文件夹拷贝一个文件

try {
    FileInputStream fis = new FileInputStream(txtfile);
    File outfile = new File(file,"bbbbb.txt");//加密后的文件，加密成功后打开是乱码
    OutputStream fileStream = new BufferedOutputStream(new FileOutputStream(outfile));
    OutputStream outputStream = crypto.getCipherOutputStream(
            fileStream,
            Entity.create("entity_id"));

    int i=0;
    byte[] buffer = new byte[1024];
    while ((i = fis.read(buffer)) > 0) {
        outputStream.write(buffer, 0, i);
        outputStream.flush();
    }

    fis.close();
    outputStream.close();
    fileStream.close();

} catch (Exception e) {
    e.printStackTrace();
}

三.文件解密

File file = new File(Environment.getExternalStorageDirectory(),"MyTest");
File infile = new File(file,"bbbbb.txt");//之前加密过的文件
File outfile = new File(file,"ccccc.txt");//解密之后的文件
try {
    FileOutputStream out = new FileOutputStream(outfile);
    BufferedOutputStream bos = new BufferedOutputStream(out);
    FileInputStream fileStream = new FileInputStream(infile);

    //加密解密过程中Entity.create("entity_id")方法的参数必须一致
    InputStream inputStream = crypto.getCipherInputStream(fileStream,Entity.create("entity_id"));

    int read;
    byte[] buffer = new byte[1024];
    while ((read = inputStream.read(buffer)) != -1) {
        bos.write(buffer, 0, read);
        bos.flush();
    }

    out.close();
    inputStream.close();
    fileStream.close();

} catch (IOException e) {
    e.printStackTrace();
} catch (KeyChainException e) {
    e.printStackTrace();
} catch (CryptoInitializationException e) {
    e.printStackTrace();
}