Hi, I am using jetpack security encryption library for encrypting the file. I have generate Master Key with below code.
MasterKey masterKey = null;
try {
masterKey = new
MasterKey.Builder(context, MasterKey.DEFAULT_MASTER_KEY_ALIAS)
.setKeyScheme(MasterKey.KeyScheme.AES256_GCM)
.build();
} catch (GeneralSecurityException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
I have encrypted my text file Sample.txt and write encrypted file to device external storage. The code as given below.
InputStream inputStream = new BufferedInputStream(appCtx.getAssets().open("Sample.txt"));
byte[] fileBytes=new byte[inputStream.available()];
inputStream.read(fileBytes);
File file = new File(Environment.getExternalStorageDirectory(), "Sample.txt");
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
EncryptedFile encryptedFile = new EncryptedFile.Builder(
appCtx,
file,
masterKey,
EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB
).build();
OutputStream outputStream = encryptedFile.openFileOutput();
outputStream.write(fileBytes);
outputStream.flush();
outputStream.close();
I put encrypted file in asset folder and now trying to decrypt but as per documentation EncryptedFile.Builder always have file Object as parameter and currently i have Inputstream after reading file from asset. So, to get file object i am writing this Inutstream to external storage as Temp.txt and passing this file for decryption. But I am getting exception as java.io.IOException: No matching key found for the ciphertext in the stream.
The code for decryption as follows:
InputStream myInputstream = new BufferedInputStream(appCtx.getAssets().open("Sample.txt"));
File enfile = createFileFromInputStream(myInputstream,appCtx);
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
EncryptedFile encryptedFile = new EncryptedFile.Builder(
appCtx,
enfile,
masterKey,
EncryptedFile.FileEncryptionScheme.AES256_GCM_HKDF_4KB
).build();
InputStream inputStream1 = encryptedFile.openFileInput();
BufferedOutputStream os1 = new BufferedOutputStream( new FileOutputStream(new File(dstPath)));
int length = 0;
byte[] buffer = new byte[1024];
while ((length = inputStream1.read(buffer)) != -1) {
os1.write(buffer, 0, length);
}
os1.close();
}
private static File createFileFromInputStream(InputStream stream, Context context) {
File f = new File(Environment.getExternalStorageDirectory(), "Temp.txt");
BufferedOutputStream os1 = null;
try {
os1 = new BufferedOutputStream( new FileOutputStream(f));
int length = 0;
byte[] buffer = new byte[1024];
while ((length = stream.read(buffer)) != -1) {
os1.write(buffer, 0, length);
}
os1.close();
stream.close();
return f;
} catch (FileNotFoundException e) {
e.printStackTrace();
}catch (IOException e) {
//Logging exception
}
return null;
}
Main Scenario: If write encrypted file to external storage and read it for decryption directly from external storage, then everything is working file. But If i paste encrypted file in asset folder and write Inputstream getting from asset folder to some temporary file and then try to decrypt it is giving error java.io.IOException: No matching key found for the ciphertext in the stream.
Please anyone help me with this issue. Thanks
