I am in need of encryption software that would keep files encrypted on the cloud as well as local on all machines.
Here is what I'm looking for:
Downloaded files saved to a particular folder on a Windows 7 or 8 machine would automatically be encrypted (after a prompt for passphrase). Ideally, this folder would be in a Dropbox or Google Drive folder, or on a thumb drive. No record of the unencrypted file would remain on the local PC (I am not worried about pieces of it on swap).
I would prefer that the files are individually encrypted with the same passphrase, rather than added to one large file which is encrypted. I don't want the cloud storage to have to recreate the whole folder, and I don't want a bit error to trash all of my files. The file names do not need to be encrypted.
Since I will be the only user in the foreseeable future, a symmetric encryption scheme would be fine.
From the cloud (preferably) or thumb drive folder, my ruby program running
on Mac OS X would edit the files. I would also want to be able to decrypt the files to view in a text editor or other software, after which I would secure erase copies of decrypted files - again, no unencrypted files on the local machine other than in swap.
This is the ideal. An alternative would be to send the files via https to a web server on the Mac (which could handle encryption in a local Mac environment) and the secure erase the files on the PC. If I did this, could I send the files unencrypted (since https will encrypt them while they are on the internet)?
True Crypt appears to be close to what I want, but it is discontinued. I don't know if I could use something like gpg, since I don't have admin privileges on the PC.
-Dan