If your encrypted backup was made with iOS 10.2 or higher, then the list of files in the backup is encrypted as well as the actual backup contents. In order to be able to read and reproduce a new list of files, Decipher Activity Transfer/Decipher Phone Refresh needs to decrypt that list of files in the backup.
Your backup password is not saved, nor is it transmitted to us or anywhere else. All of the backup filtering work is done locally on your computer. Also, just as before, Decipher Activity Transfer and Decipher Phone Refresh do not edit any of the backup contents files.
If you need help remembering your backup password, we recommend looking at our collection of tips to help you remember your iPhone backup password!