英文:
How to fix Key length 256 bits in Android
问题
在我的应用程序中，我想使用AES和CBC下载加密文件，然后在我的应用程序中解密该文件！
我在我的应用程序中编写了以下代码，但在应用程序中显示以下错误：
E/newDecryptLog: 0：密钥长度不是128/192/256位。
我的密码是：7BOF%aZQMpfJ#2wUS*S6!@K+ZB$Sz+J0
我的代码如下：
public class EncryptDecryptUtils {
public static EncryptDecryptUtils instance = null;
private static PrefUtils prefUtils;
public static EncryptDecryptUtils getInstance(Context context) {
if (null == instance)
instance = new EncryptDecryptUtils();
if (null == prefUtils)
prefUtils = PrefUtils.getInstance(context);
return instance;
}
public static byte[] encode(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length, KEY_SPEC_ALGORITHM);
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM, PROVIDER);
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(new byte[cipher.getBlockSize()]));
return cipher.doFinal(fileData);
}
public static byte[] decode(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] decrypted;
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM, PROVIDER);
cipher.init(Cipher.DECRYPT_MODE, yourKey, new IvParameterSpec(new byte[cipher.getBlockSize()]));
decrypted = cipher.doFinal(fileData);
return decrypted;
}
public void saveSecretKey(SecretKey secretKey) {
String encodedKey = Base64.encodeToString(secretKey.getEncoded(), Base64.NO_WRAP);
prefUtils.saveSecretKey(encodedKey);
}
public SecretKey getSecretKey() {
String encodedKey = "7BOF%aZQMpfJ#2wUS*S6!@K+ZB$Sz+J0";
if (null == encodedKey || encodedKey.isEmpty()) {
SecureRandom secureRandom = new SecureRandom();
KeyGenerator keyGenerator = null;
try {
keyGenerator = KeyGenerator.getInstance(KEY_SPEC_ALGORITHM);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
keyGenerator.init(OUTPUT_KEY_LENGTH, secureRandom);
SecretKey secretKey = keyGenerator.generateKey();
saveSecretKey(secretKey);
return secretKey;
}
byte[] decodedKey = Base64.decode(encodedKey, Base64.NO_WRAP);
SecretKey originalKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, KEY_SPEC_ALGORITHM);
return originalKey;
}
}
我在上面的类中使用了以下代码：
@Nullable
public static byte[] decryptFile(Context context, String fileName) {
try {
byte[] fileData = FileUtils.readFile(FileUtils.getFilePath(context, fileName));
byte[] decryptedBytes = EncryptDecryptUtils.decode(EncryptDecryptUtils.getInstance(context).getSecretKey(), fileData);
return decryptedBytes;
} catch (Exception e) {
Log.e("newDecryptLog", "0 : " + e.getMessage());
}
return null;
}
但是当使用此方法时，会捕获异常并显示上面的错误！如何修复它？
英文:
In my application i want download encrypted file with AES , CBC and decrypt this file into my app!<br>
I write below codes in my application but after application show me this error in logcat :
E/newDecryptLog: 0 : Key length not 128/192/256 bits.
My password is : 7BOF%aZQMpfJ#2wUS*S6!@K+ZB$Sz+J0
My codes is :
public class EncryptDecryptUtils {
public static EncryptDecryptUtils instance = null;
private static PrefUtils prefUtils;
public static EncryptDecryptUtils getInstance(Context context) {
if (null == instance)
instance = new EncryptDecryptUtils();
if (null == prefUtils)
prefUtils = PrefUtils.getInstance(context);
return instance;
}
public static byte[] encode(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] data = yourKey.getEncoded();
SecretKeySpec skeySpec = new SecretKeySpec(data, 0, data.length, KEY_SPEC_ALGORITHM);
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM, PROVIDER);
cipher.init(Cipher.ENCRYPT_MODE, skeySpec, new IvParameterSpec(new byte[cipher.getBlockSize()]));
return cipher.doFinal(fileData);
}
public static byte[] decode(SecretKey yourKey, byte[] fileData)
throws Exception {
byte[] decrypted;
Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM, PROVIDER);
cipher.init(Cipher.DECRYPT_MODE, yourKey, new IvParameterSpec(new byte[cipher.getBlockSize()]));
decrypted = cipher.doFinal(fileData);
return decrypted;
}
public void saveSecretKey(SecretKey secretKey) {
String encodedKey = Base64.encodeToString(secretKey.getEncoded(), Base64.NO_WRAP);
prefUtils.saveSecretKey(encodedKey);
}
public SecretKey getSecretKey() {
String encodedKey = "7BOF%aZQMpfJ#2wUS*S6!@K+ZB$Sz+J0";
if (null == encodedKey || encodedKey.isEmpty()) {
SecureRandom secureRandom = new SecureRandom();
KeyGenerator keyGenerator = null;
try {
keyGenerator = KeyGenerator.getInstance(KEY_SPEC_ALGORITHM);
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
}
keyGenerator.init(OUTPUT_KEY_LENGTH, secureRandom);
SecretKey secretKey = keyGenerator.generateKey();
saveSecretKey(secretKey);
return secretKey;
}
byte[] decodedKey = Base64.decode(encodedKey, Base64.NO_WRAP);
SecretKey originalKey = new SecretKeySpec(decodedKey, 0, decodedKey.length, KEY_SPEC_ALGORITHM);
return originalKey;
}
}
I used with this codes for above class :
@Nullable
public static byte[] decryptFile(Context context, String fileName) {
try {
byte[] fileData = FileUtils.readFile(FileUtils.getFilePath(context, fileName));
byte[] decryptedBytes = EncryptDecryptUtils.decode(EncryptDecryptUtils.getInstance(context).getSecretKey(), fileData);
return decryptedBytes;
} catch (Exception e) {
Log.e("newDecryptLog", "0 : " + e.getMessage());
}
return null;
}
But when use this run catch method and show me above error!
How can i fix it?
答案1
得分: 1
你可以将你的getSecretKey方法缩小，因为你的if条件永远不会进入"false"。你的encodedKey不是Base64字符串，而是直接的输入，可以用作密钥：
由于我在桌面Java上，不知道Android是否可用StandardCharsets。
public SecretKey getSecretKey() {
String encodedKey = "7BOF%aZQMpfJ#2wUS*S6!@K+ZB$Sz+J0";
return new SecretKeySpec(encodedKey.getBytes(StandardCharsets.UTF_8), KEY_SPEC_ALGORITHM);
}
英文:
You can shrink your getSecretKey-method as your if-clause would never run into "false". Your encodedKey is NOT
a Base64-string but the direct input and can be used as key:
As I'm on Desktop-Java I don't know if StandardCharsets are available in Android.
public SecretKey getSecretKey() {
String encodedKey = "7BOF%aZQMpfJ#2wUS*S6!@K+ZB$Sz+J0";
return new SecretKeySpec(encodedKey.getBytes(StandardCharsets.UTF_8), KEY_SPEC_ALGORITHM);
}
通过集体智慧和协作来改善编程学习和解决问题的方式。致力于成为全球开发者共同参与的知识库，让每个人都能够通过互相帮助和分享经验来进步。
评论