How Groove maintains the security of a workspace and helps protect data that is sent over a non-secure network (916359)

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Each workspace has a secret key that is distributed to all the Groove accounts that are members of the workspace. This key is used to encrypt data under the following circumstances:

• Before any data is sent over a network.
• Before data in a workspace that is not a Groove File Sharing (GFS) workspace is saved to disk.

Each recipient account then uses the key to decrypt the data before the account processes the data. This behavior provides confidentiality in the workspace so that an eavesdropper cannot read the contents of the data packet. However, Groove must also help protect the integrity of the data so that each recipient account can verify that the data was not tampered with in transit. Groove helps protect against impersonators who may want to write to and to modify the contents of the data packets.

Groove versions that are earlier than Groove 1.2 help protect data by using another common secret key that is shared by all members of the workspace. This key is used to generate a message authentication code for each data packet. However, because all member accounts of the workspace have this key, the recipients are not guaranteed that the data is sent by the member that the author claims to be. In this situation, recipients are guaranteed only that the data was sent by a workspace member.

In all workspaces that are created in Groove 1.2 or in later versions of Groove, each data packet is digitally signed by the account of the author of the data. This enables each recipient member account to verify that the data was sent by the member that the author claims to be. You may be unable to see this verification.

In Groove 1.2 and in later versions of Groove, each member of a workspace has a workspace-specific keypair that Groove uses to digitally sign the messages in the shared workspace. The public part of this keypair is stored in the member list on each device of each member. Each member account keeps its own private part of the keypair. When a data packet is first secured for transmission, the packet is encrypted by using the workspace key just as in pre-1.2 versions of Groove. Then, the packet is digitally signed by using the private part of the author's workspace-specific keypair. When the packet is received, each recipient account verifies the digital signature by using the public part of the author's workspace-specific keypair. Then, the recipient account decrypts the data by using the workspace key just as in pre-1.2 versions of Groove.

For more information about the cryptographic algorithms that are used by Groove, click the following article number to view the article in the Microsoft Knowledge Base: