Crypt4All Lite

Discussion related to AES Crypt, the file encryption software for Windows, Linux, Mac, and Java.
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tdarais
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Joined: Tue Oct 27, 2015 5:17 pm

Crypt4All Lite

Post by tdarais » Tue Oct 27, 2015 5:38 pm

Hi,

When trying to encrypt a file using Android Crypt4All I get a message "Failed to open output file." The file resides on a Micro SD card. So far as I know the Micro SD card is writable.

Also, when trying to decrypt a file in Dropbox, it says "Failed to open output directdory(not writable):/storage/sdcard1/aes" What setting will allow me to write the file to my dropbox folder? That would be my preference anyway.

Many thanks,

Tom D.

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paulej
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Re: Crypt4All Lite

Post by paulej » Wed Oct 28, 2015 12:21 pm

I think Android version 4.x wouldn't allow installed apps to write to the external SD card. Is that card to which you refer the internal or external SD card? What version of Android are you using?

tdarais
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Re: Crypt4All Lite

Post by tdarais » Fri Oct 30, 2015 12:27 am

Hi Paul,

I'm using Android Lollipop version 5.0.2 on an Xperia Z3. I did test encrypting a file on the storage native to the phone and it worked just fine.

Here's a few further nuances, a suggestion, and a curiosity:

1) So I'm guessing that encryption/decryption with files in Dropbox is not yet available?

2) In settings there is an option that says "Keep original file path." I take that to mean that the encrypted/decrypted output file will end up in the same directory as the source file, is that right? I don't have any folders "Set as encryption directory" or "Set as decryption directory" (which can be selected from a menu that appears after long pressing a folder when in the built in file manager), and when attempting to decrypt a file in the phone's native storage download folder the message I get is: "Failed to open output directory(not writable): /storage/sdcard1/aes." So it appears that Crypt4All is still attempting to write to the micro SD card even though I've selected "Keep original file path."

3) Observation/suggestion: given that the encrypt directory and decrypt directory can be set from the internal file browser, and given that settings has "Keep original file path" and "Use same directory" options, it can be a little ambiguous on what has priority . . . would there be a way to simplify that in the settings or at least show what the destination directory for encryption and for decryption is selected to be? It could show the actual path selected to be the output directory or show something generic like "same as encrypt directory" when the "Use same directory" setting has been selected. I hope this makes sense!

4) Finally, just a curiosity, at some point will there be a native Android AES Crypt app or is Crypt4All that app?

Thanks for any insight you might provide,

Tom D.

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paulej
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Re: Crypt4All Lite

Post by paulej » Fri Oct 30, 2015 4:30 am

Tom,

I did not write the Android app, so I have asked the author to comment on your post. As for the last question, both the iOS and Android versions are "native" (as I'm not sure how else to define them). They're both (AFAIK) using the core AES Crypt code, which does mean that on Android there must be some kind of JNI interface to access the C code. What are you thinking of in terms of "native"?

In any case, I did not personally plan to write separate apps for the mobile platforms, since those existing tools seem to work well.

Paul

dacker
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Re: Crypt4All Lite

Post by dacker » Fri Oct 30, 2015 8:15 am

Hi, I'm the author of Crypt4All Android app. Now as for your questions.

1. There is no Dropbox integration at this time. This would be a nice feature but I decided not to pursue it since there are many cloud storage solutions (Box, Drive,...) and I'd have to study APIs for all of them. Like Paul I don't have so much time to implement it. But it's on the feature list ;)

2. You're correct. "Keep the original file path" means that at the end of action (encryption or decryption) when you open internal file browser it'll send you to the path of the original file. If this option is not checked then it'll take you to where the file decrypted/encrypted. If you don't have set the encryption/decryption directory the encrypted/decrypted file will be in the same path as original.

As for your case, it seems that the /storage/sdcard1/aes path is not writable like the message says. With Android there are a few paths that are the same and not all of them are writable - probably symobolic linking. For example I have 4 paths on my device (Nexus 5) which point to the same path but not all of them are writable. I have: /storage/emulated/0, /storage/emulated/legacy, /storage/sdcard0 and /sdcard. Usually I use the same as the internal file browser points me to, which is /storage/emulated/0 and this one always works. Of course I can't write instructions for this because every device has different paths and different rules and for some devices also other paths are writable. There are just too many exceptions when it comes to Android system and too many combinations of devices and versions to make a rule out of it.

3. That is a good point. As I said before I'm a little bit short on time but this goes on feature list. I'm trying to simplify the process as much as possible. But originally I designed this app just for myself so the result is ugly and complicated.

4. Like Paul said my application is native. I'm using the C code for Linux and natively compile it with Android NDK. And I'm using JNI interface to use functions in the C code within Android project. I don't know if you understood any of that. For example if a new version of AESCrypt for Linux comes out I just replace the sources and compile it again. So I use the original code and it's as native as it could be.

Damjan

tdarais
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Re: Crypt4All Lite

Post by tdarais » Fri Oct 30, 2015 7:07 pm

Hi Damjan,

First I need to compliment you on Crypt4All Lite, the more I get familiar with it the more it seems like it's quite robust and up to the task! Your discussion of the app being native to Android was more extensive than my technical knowledge, but it was helpful information and it's nice to know that you can update your app quickly based on AES Crypt updates that come out. Also, it's informative for me to know that your app is the ongoing "official" AES Crypt Android app even though your app goes by a different name.

I understand that programming for Dropbox could add development complexity that isn't feasible at the present time. After better learning how to use the app on my phone's local storage, I don't have as much as a need to use it with Dropbox and it's workable to use the app as is.

I took your advice to use the /storage/emulated/0 path for encryption and decryption and it works like a charm. I've created a folder in /storage/emulated/0 called ".AES" and I do both encryption and decryption there. (I did this by long pressing the new .AES folder and then selected "set as encryption directory" and "set as decryption directory" on the pop up menu . . . I note that I could accomplish the same thing by selecting "set as encryption directory" only and then go to settings and select "Use same directory - Decryption output directory is same as encryption output directory").

Finally, you as mentioned, the path selection in the settings could use a little improvement/simplification . . . but now that I'm more familiar with the app, I understand the selections better and can better use the app as is. If you do further enhancements, though, when you have time to get to items on the features list, all the better! :D

Thanks for sharing your app with the Android community, it's great to have a Android solution for using AES Crypt.

Tom D.

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