Short message service cipher
AssigneeGreatCall, Inc.
InventorsPhilip C. Imming, Krijn van der Raadt
Life of this patent
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Abstract
A wireless phone system and methods performed thereon for cryptographically processing SMS messages is disclosed. A cryptographic pad is used to replace characters in a payload of a SMS message with coded characters. The cryptographic pad is used by the receiver of the SMS message to decode it. The cryptographic pad is one of two or more possible cryptographic pads stored in the receiver. In one embodiment, the two or more possible cryptographic pads are sent as a key where a particular cryptographic pad is referenced in the key using an index.
Claims25
A wireless handset for sending and receiving encrypted messages, the wireless handset comprising:
- a wireless transceiver;
- and
- a memory holding a key that is larger than the messages and is arranged circularly;
- wherein the wireless handset is configured to:
- obtain an index that indicates a reference point for a cryptographic pad that is a subset of the key;
- and
- perform a cryptographic algorithm that cryptographically processes a message as a function of the cryptographic pad, wherein during processing of a particular message, the cryptographic algorithm pulls a first element of the cryptographic pad from a first location in the key, and pulls subsequent elements of the cryptographic pad from subsequent locations spaced varying distances apart in the key, and wherein each of the subsequent locations is found using multiple hops through the key data from the previous location, and wherein the key value at each hop is used as input to the next hop distance.
A network controller for sending and receiving encrypted messages, the network controller comprising;
- storage holding a number of keys, each key corresponding to a respective handset, and each key being longer than messages communicated between the handsets and the network controller;
- wherein the network controller is configured to:
- identify a particular handset;
- retrieve the key corresponding to the particular handset, wherein the key is arranged circularly;
- obtain an index that indicates a reference point for a cryptographic pad that is a subset of the key;
- and
- cryptographically process a message as a function of the cryptographic pad, wherein during processing of a particular message, a first element of the cryptographic pad is pulled from a first location in the key, and subsequent elements of the cryptographic pad are pulled from subsequent locations spaced varying distances apart in the key, and wherein each of the subsequent locations is found using multiple hops through the key data from the previous location, and wherein the key value at each hop is used as input to the next hop distance.
Dependencies are inferred from the claim text.