You didn't say your OS, but you could use a solution based on encFS, flavors of which are available on Windows, Macs, Linux, and Android. BoxCryptor is probably the biggest name using encFS under the hood, and I believe it works with Amazon Cloud. I have not used BoxCryptor.
encFS will encrypt both filename and file. It works well once it's up and running. I use it to mount an encrypted Dropbox folder as a drive letter in Windows. The drive letter acts like the normal files, but the Dropbox folder looks like it's full of random junk. I can also access those encrypted files through Android once Dropbox has synced (the Android program is called EncDroid).
On my Windows system, I use encFSPlus, but I probably wouldn't recommend that any more as it seems to not be updated. This, however, looks like it might work: http://encfsmp.sourceforge.net/
Okay, here's what I'm trying now, which seems to work but it's pretty slow.
Mount your ACD with NetDrive as a network drive, then mount a 2nd network drive inside of that using EncFS MP.
Then just copy files into the EncFS drive and use it like a normal drive. EncFS will handle the encryption and Netdrive will handle the upload/download.
There are various guides available, and it has been audited with some minor things found (https://defuse.ca/audits/encfs.htm). If you're on Mac or Windows, I'd recommend http://encfsmp.sourceforge.net/ over the encfs4win + dokan combination.
No problem for me. I'm using EncFS.
For Windows & OS X: EncFS MP
For Linux: Cryptkeeper
Is really hard to say if Eds is too dificult or not for others. It works kind of the same as using Veracrypt or old Truecrypt and their containers on computer. But without root + mount as local folder Eds is not nice to use like I said. File manager of EDS itself is very limited only single panel no more tabs, no bookmarks to quickly shift locations. Or without root have to decrypt data, later shred
If you buy Eds you"ll have 2 hours to uninstall via Play Store and get refund. To have more effective time to try it out within refund window can make Veracrypt (www.veracrypt.org) container with files (docs, a video, photo's, etc) on computer, put that container on phone. Then buy and can open and experiment with ready container immediately.
Without root I might try again EncFs on Android with MixPlorer. I found that very easy to use. (Create EncFs folder via '+'). EncFs not the best encryption anymore, but for me safe enough. (MixPlorer supports aescrypt too, but that does not hide filenames). However opening MiXplorer opened EncFs folder automaticly when I tried, did not yet look into that. (Encfs Windows & OSX: http://encfsmp.sourceforge.net/ )
I use ACDDokan to mount ACD: https://github.com/Rambalac/ACDDokanNet
then EncFSMP to re-mount the drive encrypted: http://encfsmp.sourceforge.net/
Then I just use Filebot to move and rename the files. I find Windows easier than Linux to download and sort the media, but to play files via Plex a Linux VPS is really easy to set up and get working with the same encryption you have on Windows.
If you run into any problems let me know