Patent ID: 9735954
Date: 2017-08-15
CPC Classifications: H04L

Claim:
1. A method comprising: determining the allocated keyspace of a subset difference tree, the allocated keyspace being traversable by a set of cryptographic triple functions; selecting an unused key of the subset difference tree; selecting a traversal function that is a cryptographic triple function not contained in the set of cryptographic triple functions; providing a key bundle encoded in a non-transient machine-readable medium, the key bundle comprising the unused key and an identifier identifying the traversal function, the identifier providing description of the traversal function sufficient to derive the traversal function; and providing encrypted content, the encrypted content being decryptable by: determining the traversal function corresponding to the identifier; traversing the subset difference tree using the unused key and the traversal function to obtain a content cryptographic key; and applying the content cryptographic key to the encrypted content to obtain decrypted content.