Key management in a wireless network using primary and secondary keys
AssigneeElster Solutions, LLC
InventorJeff D. McCullough
Life of this patent
Estimating the term…
Abstract
A primary key may be used for a first attempt by a remote node to decrypt incoming messages from a master. In the event the decrypt attempt fails at the remote node, a secondary key may then be used to attempt to decrypt the message. Initially, the primary and secondary keys may be the same. A field tool, such as a hand-held programming unit operated by a technician at a remote node location, may change the secondary key, but may not cause any change to the primary key. The secondary key may remain so changed until a new primary key is verified and/or authenticated and the secondary key is overwritten with the new primary key. The primary key may only be changed/set by the master via an encrypted request. A technician may not use a field tool to change a primary key.
Claims16
A node of a wireless communications network, the node being remote from a master node of the wireless communications network, the master node and the node communicating via the wireless communications network, the node comprising:
- a wireless communications interface for communicating via the wireless communications network;
- a primary key for encrypting and decrypting messages in accordance with a symmetric key encryption algorithm;
- a secondary key for encrypting and decrypting messages in accordance with the symmetric key encryption algorithm;
- and
- a processor that operates to:
- receive an encrypted message from the master node via the wireless communications interface;
- attempt to decrypt the received encrypted message using the primary key;
- if the attempt to decrypt the received encrypted message using the primary key fails, attempt to decrypt the received encrypted message using the secondary key;
- and
- if the attempt to decrypt the received encrypted message using the secondary key fails, receive a command transmitted by a source local to the node to change the secondary key;
- change the secondary key in response to the command;
- and
- use the changed secondary key to perform encrypted communications with the master node via the wireless communications interface to obtain a new primary key from the master node,
- wherein the processor locally generates the primary key based at least in part on a combination of a primary seed value and an identifier that uniquely identifies the node on the wireless communications network, and wherein the processor locally generates the secondary key based at least in part on a combination of a secondary seed value and the identifier that uniquely identifies the node on the wireless communications network, and wherein the primary seed value and the secondary seed value are stored locally within a memory of the node.
A method for use in a wireless communications network comprising a master node and a first node remote from the master node, the first node and the master node communicating plurality via the wireless communications network, the first node having a wireless communications interface for communicating via the wireless communications network, a primary key for encrypting and decrypting messages in accordance with a symmetric key encryption algorithm, and a secondary key for encrypting and decrypting messages in accordance with the symmetric key encryption algorithm, the method comprising:
- locally generating the primary key based at least in part on a combination of a primary seed value and an identifier that uniquely identifies the first node on the wireless communications network, and locally generating the secondary key based at least in part on a combination of a secondary seed value and the identifier that uniquely identifies the first node on the wireless communications network;
- storing the primary seed value and the secondary seed value within a memory of the first node;
- receiving an encrypted message from the master node via the wireless communications interface;
- attempting to decrypt the received encrypted message using the primary key;
- if the attempt to decrypt the received encrypted message using the primary key fails, attempting to decrypt the received encrypted message using the secondary key;
- if the attempt to decrypt the received encrypted message using the secondary key fails, receiving a command transmitted by a source local to the first node to change the secondary key and changing the secondary key in response to the command;
- and
- using the changed secondary key to perform encrypted communications with the master node via the wireless communications interface to obtain a new primary key from the master node.
Dependencies are inferred from the claim text.