If you haven't already, download and install GoodSync.
OneFile allows a user to compress and encrypt a series of files into a simple, individual file. You may replicate data to/from an encrypted OneFile format by selecting OneFile from the list of supported services.
If you are backing up and encrypting data to a OneFile format for the first time, ensure OneFile is set as the destination folder and click Browse. 
Give the new OneFile a name in the "File name" field at bottom, then press Open.
Enter a password into the password field so that any data placed into the OneFile may be encrypted. This password will be used for both encryption and decryption moving forward. Press Go.
The OneFile will now enumerate as a folder. Press OK to set this location for the job.
To decrypt and decompress data from a OneFile, select the existing OneFile as the source. Ensure the proper password is set and press OK.
Select a recipient folder as the destination, then Analyze and Sync.
All encrypted and compressed files will be decrypted and placed into the recipient folder.
Note: A 2-way sync will treat the OneFile location as both a source and destination, and it will allow for both decryption and encryption as needed, depending on the flow of data.