When "Encrypt Downloaded Images" is selected, and "Enter Key..." is pressed in 5, a key dialog will pop up allowing users to select a key (see left) for encryption.

Users can select one of

1. (Load a key from a file) Users can use a previously generated key file to encrypt subsequent downloads. To browse for a file, use "Browse...". If no such file exists and users want to generate a key, select "Generate Key file...". Once a key file is generated, users will be prompted to save it. Once it is saved, it will be automatically loaded into the mi2b2 client. The same key file can be shared by multiple users to ensure every user on the same project can read these images once downloaded.
2. (Enter a key to generate a key) Users can also enter a key-phrase to generate a key. These keys are generated from a key phrase at least 8 characters long entered directly from the user and concatenated with the user's ID. These keys are meant for single-person use only. Sharing a key phrase with another user will not allow them to generate the same key (because the key generation also takes in user ID).
3. (Use no encryption) Users can also opt not to use encryption. This is not a default choice as users need to consider carefully whether using "No Encryption" is appropriate.