Network compromise recovery methods and apparatus
AssigneeMotorola, Inc.
InventorsCurtis Lee Cornils, Erwin Perry Comer
Life of this patent
Estimating the term…
Abstract
A secure communications system (100, FIG. 1) with a compromised communications node can quickly recover from the compromised condition by sending re-keying messages using a key encryption key hierarchy (200, FIG. 2). Each communications node (330, FIG. 3) includes a memory (300, FIG. 3) with a list of tier-group specific key encryption keys, and whenever a message arrives that is encrypted with a key encryption key in the list, the communications node decrypts the message. When the message includes a new traffic encryption key, the communications node has been re-keyed. Key encryption keys are managed hierarchically such that many communications nodes can be re-keyed with very few broadcast messages, thereby saving communications resources.
Claims9
A method of excising a compromised node from a community of nodes capable of information sharing comprising:
- for each group in a plurality of top tier groups in a top level tier, encrypting a new traffic encryption key using a top tier-group specific key encryption key, wherein the plurality of top tier groups excludes a group that includes the compromised node;
- broadcasting the new traffic encryption key to each of the plurality of top tier groups in the top level tier;
- and
- within the group that includes the compromised node, recursively broadcasting the new traffic encryption key to groups of nodes at a succession of lower tiers, until the compromised node is excised, wherein recursively broadcasting comprises:
- for each of the groups of nodes in the succession of lower tiers, each of the groups of nodes excluding a lower tier group that includes the compromised node, encrypting the new traffic encryption key using a lower tier-group specific key encryption key.
A method of operating a key management center to excise a compromised node comprising:
- from a list of top tier key encryption keys, selecting a top tier key encryption key that does not correspond to a group that includes the compromised node;
- encrypting a new traffic encryption key using the top tier key encryption key, to produce a first encrypted traffic encryption key;
- broadcasting a message that includes the first encrypted traffic encryption key;
- from a list of lower tier key encryption keys, selecting a lower tier key encryption key that does not correspond to the group that includes the compromised node;
- encrypting the new traffic encryption key using the lower tier key encryption key, to produce a second encrypted traffic encryption key;
- and
- broadcasting a message that includes the second encrypted traffic encryption key.
Dependencies are inferred from the claim text.