Thank you for contacting us and I'm sorry about the issue you are experiencing. mSecure backup files are encrypted with the login password (mSecure 4 or below) or account password (mSecure 5) that was in use when the backup file was created. In order to restore from a backup file, you will need to know it's password.
I am unable to restore a backup. Whether on my Mac or iPhone, I get the same error in both places: "Incorrect password. That is not the correct password." I have three backup files on iCloud from the last three months, and get the same error no matter which one I try to restore.