java和android文件加密小结

　　最近遇到一个文件加密的问题，自己读写的，安全性虽然还可以，但是速度慢，影响体验。

　　Cipher虽然速度相当快，但是android和java有某些api存在不兼容；

　　问题解决：

　　　　方法引用自：https://www.jianshu.com/p/2aa5e1a1df1a

　　　　还是使用cipher，算法中用到了一个填充向量，即VIPARA, 这个向量的取值是不固定的，但是加密秘钥必须为16个字节，譬如“abcdefghabcdefgh”

　　　　

package com.example;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.InvalidAlgorithmParameterException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class MyCipher {

    public static final String VIPARA = "";
    private static final String _FILE_NAME_OF_SECRET_ = "file-secret";
    private static final String _FILE_LOC_FILE_NAME_ = "file-local";

    private static final String _SOURCE_FILE_PATH_ = "path" + File.separator + _FILE_LOC_FILE_NAME_;

    private static final String _OUTPUT_FILE_PATH_ = "path" + File.separator + _FILE_NAME_OF_SECRET_;

    public static void main(String[] args) {
        encryptFile(_FILE_NAME_OF_SECRET_, _SOURCE_FILE_PATH_, _OUTPUT_FILE_PATH_);
    }

    /**
     * 初始化 AES Cipher
     *
     * @param sKey
     * @param cipherMode
     * @return
     */
    private static Cipher initAESCipher(String sKey, int cipherMode) {
        //创建Key gen
        KeyGenerator keyGenerator = null;
        Cipher cipher = null;
        try {
            IvParameterSpec zeroIv = new IvParameterSpec(VIPARA.getBytes());
            SecretKeySpec key = new SecretKeySpec(sKey.getBytes(), "AES");
            cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
            cipher.init(cipherMode, key, zeroIv);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            e.printStackTrace();
        }
        return cipher;
    }

    /**
     * 对文件进行AES加密
     *
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @return
     */
    public static File encryptFile(String key, String sourceFilePath, String destFilePath) {
        System.out.printf(sourceFilePath);
        FileInputStream in = null;
        FileOutputStream out = null;
        File destFile = null;
        File sourceFile = null;
        try {
            sourceFile = new File(sourceFilePath);

            destFile = new File(destFilePath);
            if (sourceFile.exists() && sourceFile.isFile()) {
                if (!destFile.getParentFile().exists()) {
                    destFile.getParentFile().mkdirs();
                }
                destFile.createNewFile();
                in = new FileInputStream(sourceFile);
                out = new FileOutputStream(destFile);
                Cipher cipher = initAESCipher(key, Cipher.ENCRYPT_MODE);
                //以加密流写入文件
                CipherInputStream cipherInputStream = new CipherInputStream(in, cipher);
                byte[] cache = new byte[];
                int nRead = ;
                while ((nRead = cipherInputStream.read(cache)) != -) {
                    out.write(cache, , nRead);
                    out.flush();
                }
                cipherInputStream.close();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return destFile;
    }

    /**
     * AES方式解密文件
     *
     * @param key
     * @param sourceFilePath
     * @param destFilePath
     * @return
     */
    public static File decryptFile(String key, String sourceFilePath, String destFilePath) {
        FileInputStream in = null;
        FileOutputStream out = null;
        File destFile = null;
        File sourceFile = null;
        try {
            sourceFile = new File(sourceFilePath);
            destFile = new File(destFilePath);
            if (sourceFile.exists() && sourceFile.isFile()) {
                if (!destFile.getParentFile().exists()) {
                    destFile.getParentFile().mkdirs();
                }
                destFile.createNewFile();
                in = new FileInputStream(sourceFile);
                out = new FileOutputStream(destFile);
                Cipher cipher = initAESCipher(key, Cipher.DECRYPT_MODE);
                CipherOutputStream cipherOutputStream = new CipherOutputStream(out, cipher);
                byte[] buffer = new byte[];
                int r;
                while ((r = in.read(buffer)) >= ) {
                    cipherOutputStream.write(buffer, , r);
                }
                cipherOutputStream.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                in.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                out.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return destFile;
    }
}