I've encrypted a folder with 7-Zip 9.20, specifying 256-bit AES and a password, and the .zip file was created. But then, when I clicked on the zipped file, to my surprise, PeaZip 5.1.1, which was the registered program to open zip files, opened the file without prompting me for the password.
This means 7-Zip is storing my AES password somewhere on disk, and what is even worse, in a place where other programs can find it. This is inherently insecure. How can I disable this behavior?
Here is a picture of how I encrypted the file with 7-Zip:
And here is a picture of the dialog box (with an option for entering the keyfile) I get when I try to open any file in the .zip archive (a similar window is displayed when opening .7z files):