| Revision as of 10:43, 15 May 2012 editStfg (talk | contribs)Extended confirmed users19,656 edits tagged as {{Rough translation}}; one can only copy edit material that makes basic sense; this doesn't← Previous edit | Revision as of 17:46, 15 May 2012 edit undoJac16888 (talk | contribs)Administrators55,276 edits restore redirect to GSM until such time as someone can create it properlyNext edit → | ||
| Line 1: | Line 1: | ||
| #redirect ] | |||
| {{Rough translation|German|Deutsch}} | |||
| '''COMP128''' is an implementation of ] network-specified algorithms A3 and A8. A3 is the ] of the mobile station on the network or AuC (Authentication Center). A8 is used a ] for the ] transmission between the mobile station and the ]. | |||
| Technical details of the originally confidential algorithm arrived in 1998 by implementing ] to the public. | |||
| COMP128 works with nine rounds. The central core of the ] is a ]. This hash function provides a 128-bit hash value for 256-bit input. It is based on a butterfly structure. The output of the algorithm contains the authentication used for the response and the session key for the A5 stream cipher, which is used to encrypt the language transfer. | |||
| ==Pseudocode== | |||
| Let X, the 32-byte entry of the hash function, with K: = X the key goal of the SIM card and X sent by the station Challenge. are still , the tables T0, T1, T2 , T3 and T4 the secret permuted. Then passes through the first input 8 times the following compression (according to , see Related links): | |||
| For i=0 to 4 do: | |||
| For j=0 to 2<sup>i</sup>-1 do: | |||
| For k=0 to 2<sup>4-i</sup>-1 do: | |||
| s = k + j*2<sup>5-i</sup> | |||
| t = s + 2<sup>4-i</sup> | |||
| x = (X + 2X) mod 2<sup>9-i</sup>) | |||
| y = (2X + X) mod 2<sup>9-i</sup>) | |||
| X = Ti | |||
| X = Ti | |||
| After each permutation, the 16 bytes of output in X and K are stored in X. | |||
| ==Security== | |||
| COMP128 is considered unsafe because small changes in the hash input are not sufficiently dispersed. Due to the ], the system can be exploited to, for example, extract the ] card's key. | |||
| == External links == | |||
| * (PDF-Datei; 8,17 MB) | |||
| * | |||
| * ''Reducing the Collision Probability of Alleged Comp128'' von H.Handschuh, P.Paillier, Springer-Verlag 2000 (PDF-Datei; 82 kB) | |||
| * | |||
| ] | |||
| ] | |||
| ] | |||
Revision as of 17:46, 15 May 2012
Redirect to: