How to share your photos in the cloud, but with your own encryption?

Question

Encryption

Task:
1. So that one person from a computer (Windows) or phone (Android) can upload and manage photos in a free cloud.
2. So that a second person from a computer (Windows) or tablet (Android) can view these photos.

Conditions:
1. Encryption of data in the cloud NOT by means of the cloud, i.e. so that the data goes to the cloud and returns already encrypted). For this, apparently, a special is installed. device program.
2. Lack of a local copy of the cloud (encrypted or not) on any device.

Part of the solution is seen as follows: on the tablet or computer of the second person there is a program - an image viewer that accesses the special. directory on the device, which is essentially virtual and which is organized by the same encryption program, which in turn accesses the cloud, takes encrypted files from there upon request and provides them decrypted on the fly to the viewer program. Similarly, everything works on the device of the first person, only the direction of the files in the other direction.

I myself use only on Windows: Encfsmp + standard cloud client, but this requires a local copy of encrypted data. And you need without a local copy (there is no space on the devices).

I ask you to suggest what software can solve the tasks.
Thank you.

Answer 1

This is not possible without a local copy. Decryption must take place on a local device, so that a clean ciphertext goes to the cloud.