A5 Cipher

[John Young]

The 3GPP algorithms are accessible here:

  http://portal.etsi.org/dvbandca/3GPP/3gppspecs.asp

However, sorry to be dense, but what is new in A5/3?
Key length to 128 bits and more openness of the cipher
for public testing?

The 3GPP specs available appear to be those around for
a while. Or have they been modified, and in what way?

On a related, one of the ETSI documents lists hooks for
A5/1 through A5/7. Is this series in the offing?

http://home.netvigator.com/~bssopr/cc.pdf

TS 100 596 V6.0.0 (1998-08)
Technical Specification
Digital cellular telecommunications system (Phase 2+);
Base Station Controller - Base Transceiver Station
(BSC - BTS) interface;
Layer 3 specification
(GSM 08.58 version 6.0.0 Release 1997)

The Algorithm Identifier field (octet 3) indicates the relevant 
ciphering algorithm. It is coded as:

0000 0000 Reserved
0000 0001 No encryption shall be used.
0000 0010 GSM encryption algorithm version 1 (A5/1)
0000 0011 GSM A5/2
0000 0100 GSM A5/3
0000 0101 GSM A5/4
0000 0110 GSM A5/5
0000 0111 GSM A5/6
0000 1000 GSM A5/7

And other A5/3-related URLs:


http://www.3gpp.org/ftp/tsg_sa/WG3_Security/2000_meetings/TSGS3_12_Stockhol
m/Docs/PDF/S3-000227.pdf


http://www.3gpp.org/ftp/tsg_sa/WG3_Security/2000_meetings/TSGS3_13_Yokohama
/Docs/PDF/s3-000333.pdf


http://www.3gpp.org/ftp/tsg_sa/WG3_Security/2000_meetings/TSGS3_13_Yokohama
/Docs/PDF/S3-000362.pdf


http://www.3gpp.org/ftp/tsg_sa/WG3_Security/TSGS3_18_Phoenix/Docs/PDF/S3-01
0259.pdf