diff --git a/common-tasks/backup-restore.md b/common-tasks/backup-restore.md
index 78e320fa..fadb5198 100644
--- a/common-tasks/backup-restore.md
+++ b/common-tasks/backup-restore.md
@@ -89,6 +89,14 @@ Migrating Between Two Physical Machines
 
 In order to migrate your Qubes system from one physical machine to another, simply follow the backup procedure on the old machine, [install Qubes](/downloads/) on the new machine, and follow the restoration procedure on the new machine. All of your settings and data will be preserved!
 
+Choosing a Backup Passphrase
+----------------------------
+
+Here are some things to consider when selecting a passphrase for your backups:
+
+ * If you plan to store the backup for a long time or on third-party servers, you should make sure to use a very long, high-entropy passphrase. (Depending on the decryption passphrase you use for your system drive, this may necessitate selecting a stronger passphrase. If your system drive decryption passphrase is already sufficiently strong, it may not.)
+ * An adversary who has access to your backups may try to substitute one backup for another. For example, when you attempt to retrieve a recent backup, the adversary may instead give you a very old backup containing a compromised AppVM. If you're concerned about this type of attack, you may wish to use a different passphrase for each backup, e.g., by appending a number or date to the passphrase.
+ * If you're forced to enter your system drive decryption passphrase in plain view of others (where it can be shoulder-surfed), then you may want to use a different passphrase for your backups (even if your system drive decryption passphrase is already maximally strong). On the othe hand, if you're careful to avoid shoulder-surfing and/or have a passphrase that's difficult to detect via shoulder-surfing, then this may not be a problem for you.
 
 Notes
 -----