Changing the USIM authentication method using pySim-shell

SIM Card Technology
1

Hi all,
I tried to change the USIM authentication method to comp128v1 on a SysmocomSJA2 SIM, howere when I use edit_binary_decoded and change the algorithm to "comp128v1" I got the following error:

pySIM-shell (00:MF/ADF.USIM/EF.USIM_AUTH_KEY)# read_binary_decoded
{
    "cfg": {
        "only_4bytes_res_in_3g": false,
        "sres_deriv_func_in_2g": 1,
        "use_opc_instead_of_op": true,
        "algorithm": "milenage"
    },
    "key": "****masked****",
    "op_opc": "****masked****"
}
pySIM-shell (00:MF/ADF.USIM/EF.USIM_AUTH_KEY)# edit_binary_decoded

EXCEPTION of type 'MappingError' occurred with message: Error in path (building) -> cfg -> algorithm
building failed, no mapping for 'comp128v1'

Do you know how I can change the authentication to comp128v1?

2

A USIM can never use COMP128V1 (at leat not in the USIM application).

COMP128V1 is a pure 2G SIM algorithm, and hence can only operate in the legacy GSM application, and not in ADF.USIM.

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