US 7,627,115 B2 · Method and system for implementing the GEA3 encryption algorithm for GPRS compliant handsets

Abstract

In a wireless communication system, a method and system for implementing the GEA3 encryption algorithm for GPRS compliant handsets are provided. An intermediate value may be generated based on initialized input variables, a cipher key and a key modifier. A first processing block of output bits may be generated by a keystream generator from the intermediate value, the cipher key, and an indication of the processing block of output bits being processed. Additional processing blocks of output bits may also be generated by the keystream generator based on an immediately previous processing block of output bits, the intermediate value, the cipher key, and an indication of the processing block of output bits being processed. A restart signal may indicate that subsequent processing blocks of output bits may be generated by the keystream generator by utilizing the same cipher key and the generated intermediate value.

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Claims32

Dependent claims

A method for encryption, the method comprising:

implementing GEA3 encryption by:
initializing, by one or more circuits, a keystream generator with input variables;
generating, by said one or more circuits, an intermediate value which is utilized to generate an output keystream, based on said input variables, a cipher key and a key modifier;
after generating, by said one or more circuits, a first processing block of output bits and an indicator indicating when said first processing block of output bits is generated, generating, by said one or more circuits, at least one additional processing block of output bits utilizing an immediately generated previous processing block of output bits, said generated intermediate value, said cipher key, and an indication corresponding to a processing block of output bits being processed, wherein said generating of at least one additional processing block of output bits is done after an indicator indicating when an immediately generated previous processing block of output bits is generated;
and
in response to receiving, by said one or more circuits, an indicator indicating that at least one subsequent processing block of output bits is to be generated utilizing said cipher key, generating, by said one or more circuits, at least one subsequent processing block of output bits utilizing an immediately generated previous processing block of output bits, said generated intermediate value, said cipher key, and an indication corresponding to a processing block of output bits being processed, wherein said generating of at least one subsequent processing block of output bits is done after an indicator indicating when an immediately generated previous processing block of output bits is generated.

3 more elements

A system for encryption, the system comprising:

one or more circuits for implementing GEA3 encryption, wherein said one or more circuits are operable to initialize a keystream generator with input variables;
said one or more circuits are operable to generate an intermediate value which is utilized to generate an output keystream, based on said input variables, a cipher key and a key modifier;
said one or more circuits are operable to generate a first processing block of output bits and an indicator indicating when said first processing block of output bits is generated;
said one or more circuits are operable to generate at least one additional processing block of output bits utilizing an immediately generated previous processing block of output bits, said generated intermediate value, said cipher key, and an indication corresponding to a processing block of output bits being processed, wherein said generating of at least one additional processing block of output bits is done after an indicator indicating when an immediately generated previous processing block of output bits is generated;
said one or more circuits are operable to receive an indicator indicating that at least one subsequent processing block of output bits is to be generated utilizing said cipher key;
and
said one or more circuits are operable to generate at least one subsequent processing block of output bits utilizing an immediately generated previous processing block of output bits, said generated intermediate value, said cipher key, and an indication corresponding to a processing block of output bits being processed, wherein said generating of at least one subsequent processing block of output bits is done after an indicator indicating when an immediately generated previous processing block of output bits is generated.

4 more elements

Dependencies are inferred from the claim text.

Description8,132 words

Summary2,501 words

#This application makes reference to:

#U.S. application Ser. No. 10/924,219 filed Aug. 23, 2004;

#U.S. application Ser. No. 10/924,002 filed Aug. 23, 2004;

Brief description of the drawings6 figures

#FIG. 2 is a diagram of an exemplary variable initialization for a general purpose keystream generator function KGCORE to operate as a GPRS GEA3 keystream generator function, which may be utilized in connection with an embodiment of the invention.

#FIG. 3 is a flow diagram that illustrates the operation of a general purpose keystream generator function KGCORE, which may be utilized in connection with an embodiment of the invention.

Detailed description5,408 words

#Certain embodiments of the invention may be found in a method and system for implementing the GEA3 encryption algorithm for GPRS compliant handsets. A finite state machine may be utilized to control the operation and data processing of a keystream generator system for General Packet Radio Service applications. A plurality of processing stages may be controlled by the finite state machine, where each processing stage may reuse a plurality of processing hardware blocks in the keystream generator system in accordance to the selected mode of operation. This approach may provide a cost effective integrated circuit (IC) solution capable of accelerating the encryption and decryption speed of a GPRS variant of the GEA3 algorithm and allow for a faster deployment of next generation data services.

#FIG. 1 is a block diagram of an exemplary A5/3 data encryption system for GSM communications, as disclosed in 3rd Generation Partnership Project, Technical Specification Group Services and System Aspects, 3G Security, Specification of the A5/3 Encryption Algorithms for GSM and ECSD, and the GEA3 Encryption Algorithm for GPRS, Document 1, A5/3 and GEA3 Specifications, Release 6 (3GPP TS 55.216 V6.1.0, 2002-12). Referring to FIG. 1, the GPRS/EGPRS encryption system 100 may comprise a plurality of GEA3 algorithm blocks 102. The GEA3 algorithm block 102 may be used for data encryption in GPRS and may also be used in EGPRS which achieves higher data rates through an 8 Phase Shift Key (PSK) modulation scheme. A Logical Link Control (LLC) layer is the lowest protocol layer that is common to both an MS and a Serving GPRS Support Node (SGSN). As a result, the GEA3 encryption may take place on the LLC layer.

#When ciphering is initiated, a higher layer entity, for example, Layer 3, may provide the LLC layer with a 64-bit key, KC, which may be used as an input to the GEA3 algorithm block 102. The LLC layer may also provide the GEA3 algorithm block 102 with a 32-bit INPUT parameter and a 1-bit DIRECTION parameter. The GEA3 algorithm block 102 may also be provided with the number of octets of OUTPUT keystream data required. The DIRECTION parameter may specify whether the current keystream will be used for upstream or downstream communication, as both directions use a different keystream. The INPUT parameter may be used so that each LLC frame is ciphered with a different segment of the keystream. This parameter is calculated from the LLC frame number, a frame counter, and a value supplied by the SGSN called the Input Offset Value (IOV).

Facts

Application

10/924,177Filed 23 Aug 2004

Published

US 2006/0039556 A123 Feb 2006

Granted

1 Dec 2009

Term ends

31 Aug 2028

Estimated · how

20 years from earliest known nonprovisional domestic filing plus recorded patent term adjustment, including 1,469 days of adjustment. Maintenance-fee lapses, terminal disclaimers and statutory extensions have not been checked. The continuity chain may be incomplete; this is not an enforceability determination.

Classification8 codes

H04L 9/0625
Block ciphers, i.e. encrypting groups of characters of a plain text message using fixed encryption transformation: with splitting of the data…
H04L 9/065
The encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions;…
H04W 12/03
Security arrangements; Authentication; Protecting privacy or anonymity: protecting confidentiality, e.g. by encryption
H04L 2209/125
Details relating to cryptographic hardware or logic circuitry: parallelization or pipelining, e.g. for accelerating processing of cryptographic…

Timeline

23 Aug 2004Application filedUS 10/924,177
3 Nov 2004Assigned to Broadcom Corporationassignment of assignor's interest
23 Feb 2006PublishedUS 2006/0039556 A1
1 Dec 2009GrantedUS 7,627,115 B2
11 Feb 2016Assigned to Bank of America, N.A., AS Collateral Agentpatent security agreement
1 Feb 2017Assigned to Avago Technologies General IP (Singapore) Pte. Ltd.assignment of assignor's interest
3 Feb 2017Assigned to Broadcom Corporationtermination and release of security interest in patents
12 Oct 2026TodayWithin its term
31 Aug 2028Term endsEstimated, includes 1,469 days of adjustment

Method and system for implementing the GEA3 encryption algorithm for GPRS compliant handsets

Life of this patent

Method and system for implementing the GEA3 encryption algorithm for GPRS compliant handsets

Life of this patent

Life of this patent

Abstract

Drawings

Drawings

Claims32

Description8,132 words

Drawings

Classification8 codes

Life of this patent

Description8,132 words