FreeCalypso > hg > fc-pcsc-tools
comparison doc/GrcardSIM2-WEKI-file @ 196:c804f2f8c138
doc/GrcardSIM2-WEKI-file article written
| author | Mychaela Falconia <falcon@freecalypso.org> |
|---|---|
| date | Sun, 07 Mar 2021 01:56:02 +0000 |
| parents | |
| children | 8c151bb01d28 |
comparison
equal
deleted
inserted
replaced
| 195:810ea92d9f47 | 196:c804f2f8c138 |
|---|---|
| 1 GrcardSIM2 cards have a proprietary EF under DF_GSM with file ID 0x0001; | |
| 2 Osmocom wiki page for this card model gives EF.WEKI as the name for this | |
| 3 proprietary file. We (FreeCalypso) have no idea as to where this name came | |
| 4 from, and where and how the people who wrote that wiki page (Sysmocom staff or | |
| 5 not - unknown) got this knowledge. This file is important because it stores Ki | |
| 6 and the selection of COMP128 algorithm version, but the same file also appears | |
| 7 to have other fields serving other purposes which are not currently understood. | |
| 8 | |
| 9 The total length of this transparent EF is 35 bytes, out of which only the first | |
| 10 19 bytes are documented in the Osmocom wiki page and written by their pySim-prog | |
| 11 tool. Let us now break down this file according to our currently available | |
| 12 limited understanding: | |
| 13 | |
| 14 * The first two bytes are always 00 10 - these byte values appear in "blank" | |
| 15 unprogrammed cards as shipped by Grcard, they also appear in the Osmocom wiki | |
| 16 page, and are programmed by pySim-prog. The purpose and meaning of these two | |
| 17 bytes are completely unknown, and we have never tried writing anything | |
| 18 different into them. | |
| 19 | |
| 20 * The next byte gives COMP128 algorithm selection plus something else that is | |
| 21 not understood: | |
| 22 | |
| 23 - The low nibble of this byte selects COMP128 algorithm version as follows: | |
| 24 | |
| 25 0 = COMP128v1 | |
| 26 1 = COMP128v2 | |
| 27 2 = COMP128v3 | |
| 28 | |
| 29 Note that the Osmocom wiki page is wrong in its description of this nibble: | |
| 30 setting this nibble to 3 ends up selecting COMP128v2 rather than v3. | |
| 31 (pySim-prog is unaffected because it always writes 0 for COMP128v1.) | |
| 32 | |
| 33 - The high nibble of this byte is not understood. Osmocom wiki page tells | |
| 34 people to write 0 into this nibble and so does pySim-prog, but the "blank" | |
| 35 unprogrammed cards we got from Grcard have it set to 2. Setting this nibble | |
| 36 to either 0 or 2 does not seem to affect the result of RUN GSM ALGORITHM | |
| 37 operations, thus it probably controls something else. | |
| 38 | |
| 39 * The next 16 bytes store Ki - this part is straightforward. | |
| 40 | |
| 41 * The last 16 bytes are not understood; our "blank" unprogrammed cards from | |
| 42 Grcard have all FFs in these bytes. |