Cannot open files in Android App ("Ein Fehler ist aufgetreten") due to Unauthentic ciphertext


my English is not so good, but I try to describe my problem. I have the same issue (ein Fehler ist aufgetreten) , I cant Download many files of my OneDrive folder on my Android phone.

I am using the last beta of the Playstore and before I tried the läßt Version without Beta. My License is only avaible with the Playstore Version, so I cant use the
package files you upload above cause I need a License file… Hope you can me help.

Version 1.10.0

I upload my log File too.
0.log (399.8 KB)

Hey and welcome to the Cryptomator Community :slightly_smiling_face:,

I just created a new topic with your issue because the other one was specific for Android 9 and was fixed in Cryptomator for Android version 1.8.0

Your log shows a lot of

D	20230602112726.868	DownloadFilesUseCase	failed 7b699ffd
D	20230602112726.873	ExceptionHandler	Unexpected error
org.cryptomator.domain.exception.FatalBackendException: Unauthentic ciphertext
	at io.reactivex.internal.operators.flowable.FlowableFromPublisher.subscribeActual(
	at io.reactivex.Flowable.subscribe(
	at io.reactivex.Flowable.subscribe(
	at io.reactivex.internal.operators.flowable.FlowableSubscribeOn$
	at io.reactivex.internal.schedulers.ExecutorScheduler$ExecutorWorker$
	at io.reactivex.internal.schedulers.ExecutorScheduler$
	at java.util.concurrent.ThreadPoolExecutor.runWorker(
	at java.util.concurrent.ThreadPoolExecutor$
Caused by: Unauthentic ciphertext
	... 14 more
Caused by: org.cryptomator.cryptolib.api.AuthenticationFailedException: Header tag mismatch.
	at org.cryptomator.cryptolib.v2.FileHeaderCryptorImpl.decryptHeader(
	at org.cryptomator.cryptolib.common.DecryptingReadableByteChannel.loadHeaderIfNecessary(
	... 15 more
Caused by: javax.crypto.AEADBadTagException: error:1e000065:Cipher functions:OPENSSL_internal:BAD_DECRYPT
	at java.lang.reflect.Constructor.newInstance0(Native Method)
	at java.lang.reflect.Constructor.newInstance(
	at javax.crypto.Cipher.doFinal(
	at org.cryptomator.cryptolib.v2.FileHeaderCryptorImpl.decryptHeader(
	... 17 more

ErrorCode: FDOG:1C4A


Not sure yet what happened to files like p5Xbw4CebPmYd-FsP_Uoq-KJXOnK7cmoswW63v0ckhczkotvSSEb72FT.c9r in the vault folder.

Thx, have you a link for the new Topic? Im New here in the community, hope you find my erros?

This thread is the new topic :grinning:

Saw it… Thx, hope someone can find the solution and fix the Problem. Cause I cant use the App with this error :grimacing:

Any ideas, what I can do? I paid for the App and still cant use it… Maybe I can get a serial for the App from your Site? So I dont have to use the App Form Playstore, maybe that solved the Problem? Im not a Programme Only a User.

I’m sorry for the late response.

Can you open those files using the desktop app?

If not, can you please share the log file of the desktop app as well after enabling debug mode and trying to access this file? Where is the log file located?

The license key does not have any influence on that.

I have news, when I opened the post, I did not have access to my PC. In retrospect, I realize that I left out a few important core pieces of information to get to the bottom of the “problem,” and for that I would like to apologize first!

Initial situation:

Everything done on the PC

Using the software “RaiDrive” I made a network drive from the OneDrive storage so that I could create a Cryptomator Vault on OneDrive and access files without having to download them. Later, I found “Cyberduck,” which has Cryptomator integrated, and through it, I have the ability to download and upload individual files from my Vault, as it is quite slow via RaiDrive I upload everything via “Cyberduck.” The files can also be opened normally on the PC via “Cyberduck,” but not on the phone. So is the problem with Cyberduck? If so, are there any suggestions for improving my application needs?

Again, in summary, what I want:

  1. I want the data encrypted on OneDrive.
  2. I want to be able to access files without having to download them every time, like a network drive with “RaiDrive”
  3. I want to be able to upload and download individual files from both my phone and my PC.

Note: Unfortunately, Cryptomator in the desktop version does not offer direct connection to OneDrive (or am I too stupid?), so I went all these “detours.”

I hope I was able to shed some light on the matter and hope for support.

Best regards


I dont think so. I do the same without problems. The reason why you cant open the files is the error you posted initially?

If you want to encrypt/decrypt a file local, you have to download it at some point.
If you do not want to have all of your files local all the time, you can configure the OneDrive client to download files on demand. That works with encrypted cryptomator vault files as well.

You are not. The desktop app is designed to work with the storage provider client.