A5 GSM Encryption.


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Encryption watchwords. Symmetric algorithmsBlock ciphersStream ciphersPublic key algorithmsOne-way hash capacities. Ki. GSM Security Features. Dispersion of security featuresSIM=A3
Transcripts
Slide 1

Ki A5 GSM Encryption Kingdom Special Operations SJS-KW

Slide 2

Ki Encryption catchphrases Symmetric calculations Block figures Stream figures Public key calculations One-way hash capacities

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MSC BS MS SIM GSM Security Features Distribution of security components SIM= A3 & A8 IMSI Ki TMSI/LAI Kc/CKSN MS= A5 BS= A5 Kc [TMSI/IMSI = VLR]

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Ki MS BS GSM Security Features Authentication MS and system process SRES from RAND Network [VLR] analyzes comes about RAND SRES = A3(RAND , Ki) SRES = A3(RAND , Ki) =? Come up short Authentication Successful

Slide 5

Ki MS BS GSM Security Features Key era K c is processed from RAND Kc = A8(RAND , Ki) Kc = A8(RAND , Ki) K c K c A5 DATA TDMA outline TDMA outline

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Ki How A5 GSM Encryption run Three clock controlled LFSRs Feedback polynomials have degree 19,23, and 22 (their total is 64) The 64-bit figure key instates the LFSRs 22-bit TDMA outline number is bolstered in Two 114-piece key streams (uplink and downlink)

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Ki REG_FILE 9x16 Bit LFSR CONTROL CIP_SEQ_RAM 30x8 Bit cip_data A5 GSM Encryption of information cip_key:86 A5 mode begin done ld_key clk_en cip_bit sel clk AT MS* AT BTS* reset information wr include sel cip_add

Slide 8

Ki A5 GSM x3 register Encryption LFSRs R1 : 19 Out Func R2 : 23 R3 : 22 Clock Control Kc : 64 Frame: 22

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Ki A5 GSM Encryption FSM CONTROL inactive burden key move 100 blk_1 blk_2 done

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Ki A5 GSM Encryption Registers TMDA Frame number 22Bits Kc Cipher Key 64

Slide 11

Ki A5.1 versus A5.2 Export limitations A5.1 calculation is not exportable to assigned nations [Only In Europe] A5.2 calculation adjusted for fare Implementation Differences A5.1 A5.2 Output capacity Clock Control unit

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