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我正在使用简单的CipherInput/OutputStream尝试在android中加密/解密文件。Android中的CipherOutputStream损坏头文件
我遇到的问题是,它似乎是破坏文件的前几个字节,但没有其余的。下面是一个简单的文本文件输出的例子:
原始文本:
"Test for Android cipher. The quick brown fox jumps over the lazy dog."
通过加密和解密通电操作:
@ÍØJb¢çc°ÌHOšpher. The quick brown fox jumps over the the lazy dog.
这里是我的代码:
public static SecretKey generateKey(Context c, char[] passphraseOrPin) throws NoSuchAlgorithmException, InvalidKeySpecException {
// Number of PBKDF2 hardening rounds to use. Larger values increase
// computation time. You should select a value that causes computation
// to take >100ms.
byte[] salt = Settings.Secure.getString(c.getContentResolver(),
Settings.Secure.ANDROID_ID).getBytes();
final int iterations = 1000;
final int outputKeyLength = 128;
SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(passphraseOrPin, salt, iterations, outputKeyLength);
SecretKey secretKey = secretKeyFactory.generateSecret(keySpec);
Log.d("HIDEMYPICS","Secret Key: " + toHex(secretKey.getEncoded()));
return secretKey;
}
public static boolean decryptFileFromUri(Context context, Uri file, String keyphrase) {
try {
File f = new File(getRealPathFromURI(context, file));
FileInputStream fis = new FileInputStream(f);
File ef = new File(f.toString().replace(".epf", ""));
FileOutputStream fos = new FileOutputStream(ef);
Log.d("HIDEMYPICS","Decrypting: " + f.toString());
SecretKey key = generateKey(context, keyphrase.toCharArray());
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, key);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = fis.read(d)) != -1) {
cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
fis.close();
Log.d("HIDEMYPICS","Decrypted to: " + ef.toString());
return true;
} catch (IOException e){
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
return false;
}
public static boolean encryptFileFromUri(Context context, Uri file, String keyphrase) {
try {
File f = new File(getRealPathFromURI(context, file));
FileInputStream fis = new FileInputStream(f);
File ef = new File(f.toString() + ".epf");
FileOutputStream fos = new FileOutputStream(ef);
Log.d("HIDEMYPICS","Encrypting: " + f.toString());
SecretKey key = generateKey(context, keyphrase.toCharArray());
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key);
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = fis.read(d)) != -1) {
cos.write(d, 0, b);
}
// Flush and close streams.
cos.flush();
cos.close();
fis.close();
Log.d("HIDEMYPICS","Encrypted to: " + ef.toString());
return true;
} catch (IOException e){
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (InvalidKeySpecException e) {
e.printStackTrace();
}
return false;
}
更新:
被告知随机IV明确添加到密码设置和添加/修改的下列代码行,以方便它:
SecureRandom r = new SecureRandom();
byte[] ivBytes = new byte[16];
r.nextBytes(ivBytes);
SecretKey key = generateKey(context, keyphrase.toCharArray());
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(ivBytes));
结束了相同的结果。文本文件的前几个字节仍然损坏。
最终的答案:
不知道我做什么,但每个建议下面我尝试了静态IV和它仍然显示出相同的行为,但我感动的声明和事情发生;可能在某处存在错字。这个问题现在已经解决了,这是最终的工作代码。感谢所有帮助!
private static final byte[] ivBytes = {109,15,57,79,75,112,50,91,18,18,107,127,65,68,12,69};
public static SecretKey generateKey(Context c, char[] passphraseOrPin) throws NoSuchAlgorithmException, InvalidKeySpecException {
// Number of PBKDF2 hardening rounds to use. Larger values increase
// computation time. You should select a value that causes computation
// to take >100ms.
byte[] salt = Settings.Secure.getString(c.getContentResolver(),
Settings.Secure.ANDROID_ID).getBytes();
final int iterations = 1000;
final int outputKeyLength = 128;
SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
KeySpec keySpec = new PBEKeySpec(passphraseOrPin, salt, iterations, outputKeyLength);
SecretKey secretKey = secretKeyFactory.generateSecret(keySpec);
return secretKey;
}
public static boolean decryptFileFromUri(Context context, Uri file, String keyphrase) {
try {
File f = new File(getRealPathFromURI(context, file));
FileInputStream fis = new FileInputStream(f);
File ef = new File(f.toString().replace(".epf", ""));
FileOutputStream fos = new FileOutputStream(ef);
SecretKey key = generateKey(context, keyphrase.toCharArray());
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(ivBytes));
// Wrap the output stream
CipherInputStream cis = new CipherInputStream(fis, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = cis.read(d)) != -1) {
fos.write(d, 0, b);
fos.flush();
}
// Flush and close streams.
fos.close();
cis.close();
f.delete();
return true;
} catch (IOException e){
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (InvalidKeySpecException e) {
e.printStackTrace();
} catch (InvalidAlgorithmParameterException e) {
e.printStackTrace();
}
return false;
}
public static boolean encryptFileFromUri(Context context, Uri file, String keyphrase) {
try {
File f = new File(getRealPathFromURI(context, file));
FileInputStream fis = new FileInputStream(f);
File ef = new File(f.toString() + ".epf");
FileOutputStream fos = new FileOutputStream(ef);
SecretKey key = generateKey(context, keyphrase.toCharArray());
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
cipher.init(Cipher.ENCRYPT_MODE, key, new IvParameterSpec(ivBytes));
// Wrap the output stream
CipherOutputStream cos = new CipherOutputStream(fos, cipher);
// Write bytes
int b;
byte[] d = new byte[8];
while ((b = fis.read(d)) != -1) {
cos.write(d, 0, b);
cos.flush();
}
// Flush and close streams.
cos.close();
fis.close();
f.delete();
return true;
} catch (IOException e){
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (InvalidKeyException e) {
e.printStackTrace();
} catch (InvalidKeySpecException e) {
e.printStackTrace();
} catch (InvalidAlgorithmParameterException e) {
e.printStackTrace();
}
return false;
}
试过了,不幸的是没有工作:/。同样的结果。该文件的前几个字节已损坏。在上面添加了关于它的更新。 – Nuvious
这是一个约11个单词的句子,你仍然只能阅读它的第一部分。 IV在加密和解密期间必须相同。 –
我会尝试获取密文的一个例子,但它会将整个消息正面加密;你看到的是解密的消息。我也尝试过使用上面的随机设置静态128位四副,仍然没有喜悦。 – Nuvious