'''All''' of your Firefox Sync data is stored such that only you and nobody else can read your data. When you configure Firefox Sync, a Sync Key is generated. You can think of this key as a digital version of a key you use to open doors, safes, etc. When you send data to a Sync server, Sync creates a digital safe on your local computer, puts your data in that safe, then uses the Sync Key to lock it. The digital safe is then transferred to and stored on the Sync Server. Your Sync Key is the only key in the universe that can open these digital safes and there is no other way to crack the safe. If someone accesses your Sync data on the Sync server, they only see your digital safe, not what's inside. The Sync Keys are generated such that it would take thousands of computers all working together many years to duplicate your key and unlock your safes and the data inside. Use of Sync Key to protect your data is required. It is not possible to change your settings to not use a Sync Key. =Tell Me More= A Sync Key is a cryptographically secure randomly-generated key. It is generated by the Sync client when you initially configure Sync. The Sync Key is used to encrypt data before being sent to the server. The Sync Key is never transmitted to the Sync Server, so the server nor the people with access to it know how to decrypt your stored data. More technical information is [http://docs.services.mozilla.com/sync/overview.html available].

All of your Firefox Sync data is stored such that only you and nobody else can read your data.

When you configure Firefox Sync, a Sync Key is generated. You can think of this key as a digital version of a key you use to open doors, safes, etc.

When you send data to a Sync server, Sync creates a digital safe on your local computer, puts your data in that safe, then uses the Sync Key to lock it. The digital safe is then transferred to and stored on the Sync Server.

Your Sync Key is the only key in the universe that can open these digital safes and there is no other way to crack the safe. If someone accesses your Sync data on the Sync server, they only see your digital safe, not what's inside. The Sync Keys are generated such that it would take thousands of computers all working together many years to duplicate your key and unlock your safes and the data inside.

Use of Sync Key to protect your data is required. It is not possible to change your settings to not use a Sync Key.

Tell Me More

A Sync Key is a cryptographically secure randomly-generated key. It is generated by the Sync client when you initially configure Sync. The Sync Key is used to encrypt data before being sent to the server.

The Sync Key is never transmitted to the Sync Server, so the server nor the people with access to it know how to decrypt your stored data.

More technical information is available.