docs: add SUPI/SUCI usage example
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+
+Guide: Enabling 5G SUCI
+========================
+
+SUPI/SUCI Concealment is a feature of 5G-Standalone (SA) to encrypt the
+IMSI/SUPI with a network operator public key. 3GPP Specifies two different
+variants for this:
+
+* SUCI calculation *in the UE*, using data from the SIM
+* SUCI calculation *on the card itself*
+
+pySIM supports writing the 5G-specific files for *SUCI calculation in the UE* on USIM cards, assuming that
+your cards contain the required files, and you have the privileges/credentials to write to them. This is
+the case using sysmocom sysmoISIM-SJA2 cards (or successor products).
+
+In short, you can enable SUCI with these steps:
+
+* activate USIM **Service 124**
+* make sure USIM **Service 125** is disabled
+* store the public keys in **SUCI_Calc_Info**
+* set the **Routing Indicator** (required)
+
+If you want to disable the feature, you can just disable USIM Service 124 (and 125).
+
+Technical References
+~~~~~~~~~~~~~~~~~~~~
+
+This guide covers the basic workflow of provisioning SIM cards with the 5G SUCI feature. For detailed information on the SUCI feature and file contents, the following documents are helpful:
+
+* USIM files and structure: `TS 31.102 <https://www.etsi.org/deliver/etsi_ts/131100_131199/131102/16.06.00_60/ts_131102v160600p.pdf>`__
+* USIM tests (incl. file content examples) `TS 31.121 <https://www.etsi.org/deliver/etsi_ts/131100_131199/131121/16.01.00_60/ts_131121v160100p.pdf>`__
+
+For specific information on sysmocom SIM cards, refer to Section 9.1 of the `sysmoUSIM User
+Manual <https://www.sysmocom.de/manuals/sysmousim-manual.pdf>`__.
+
+--------------
+
+Admin PIN
+---------
+
+The usual way to authenticate yourself to the card as the cellular
+operator is to validate the so-called ADM1 (admin) PIN. This may differ
+from card model/vendor to card model/vendor.
+
+Start pySIM-shell and enter the admin PIN for your card. If you bought
+the SIM card from your network operator and don’t have the admin PIN,
+you cannot change SIM contents!
+
+Launch pySIM:
+
+::
+
+ $ ./pySim-shell.py -p 0
+
+ Using PC/SC reader interface
+ Autodetected card type: sysmoISIM-SJA2
+ Welcome to pySim-shell!
+ pySIM-shell (MF)>
+
+Enter the ADM PIN:
+
+::
+
+ pySIM-shell (MF)> verify_adm XXXXXXXX
+
+Otherwise, write commands will fail with ``SW Mismatch: Expected 9000 and got 6982.``
+
+Key Provisioning
+----------------
+
+::
+
+ pySIM-shell (MF)> select MF
+ pySIM-shell (MF)> select ADF.USIM
+ pySIM-shell (MF/ADF.USIM)> select DF.5GS
+ pySIM-shell (MF/ADF.USIM/DF.5GS)> select EF.SUCI_Calc_Info
+
+By default, the file is present but empty:
+
+::
+
+ pySIM-shell (MF/ADF.USIM/DF.5GS/EF.SUCI_Calc_Info)> read_binary_decoded
+ missing Protection Scheme Identifier List data object tag
+ 9000: ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff -> {}
+
+The following JSON config defines the testfile from `TS 31.121 <https://www.etsi.org/deliver/etsi_ts/131100_131199/131121/16.01.00_60/ts_131121v160100p.pdf>`__ Section 4.9.4 with
+test keys from `TS 33.501 <hhttps://www.etsi.org/deliver/etsi_ts/133500_133599/133501/16.05.00_60/ts_133501v160500p.pdf>`__ Annex C.4. Highest priority (``0``) has a
+Profile-B (``identifier: 2``) key in key slot ``1``, which means the key
+with ``hnet_pubkey_identifier: 27``.
+
+.. code:: json
+
+ {
+ "prot_scheme_id_list": [
+ {"priority": 0, "identifier": 2, "key_index": 1},
+ {"priority": 1, "identifier": 1, "key_index": 2},
+ {"priority": 2, "identifier": 0, "key_index": 0}],
+ "hnet_pubkey_list": [
+ {"hnet_pubkey_identifier": 27,
+ "hnet_pubkey": "0272DA71976234CE833A6907425867B82E074D44EF907DFB4B3E21C1C2256EBCD1"},
+ {"hnet_pubkey_identifier": 30,
+ "hnet_pubkey": "5A8D38864820197C3394B92613B20B91633CBD897119273BF8E4A6F4EEC0A650"}]
+ }
+
+Write the config to file (must be single-line input as for now):
+
+::
+
+ pySIM-shell (MF/ADF.USIM/DF.5GS/EF.SUCI_Calc_Info)> update_binary_decoded '{ "prot_scheme_id_list": [ {"priority": 0, "identifier": 2, "key_index": 1}, {"priority": 1, "identifier": 1, "key_index": 2}, {"priority": 2, "identifier": 0, "key_index": 0}], "hnet_pubkey_list": [ {"hnet_pubkey_identifier": 27, "hnet_pubkey": "0272DA71976234CE833A6907425867B82E074D44EF907DFB4B3E21C1C2256EBCD1"}, {"hnet_pubkey_identifier": 30, "hnet_pubkey": "5A8D38864820197C3394B92613B20B91633CBD897119273BF8E4A6F4EEC0A650"}]}'
+
+WARNING: These are TEST KEYS with publicly known/specified private keys, and hence unsafe for live/secure
+deployments! For use in production networks, you need to generate your own set[s] of keys.
+
+Routing Indicator
+-----------------
+
+The Routing Indicator must be present for the SUCI feature. By default,
+the contents of the file is **invalid** (ffffffff):
+
+::
+
+ pySIM-shell (MF)> select MF
+ pySIM-shell (MF)> select ADF.USIM
+ pySIM-shell (MF/ADF.USIM)> select DF.5GS
+ pySIM-shell (MF/ADF.USIM/DF.5GS)> select EF.Routing_Indicator
+ pySIM-shell (MF/ADF.USIM/DF.5GS/EF.Routing_Indicator)> read_binary_decoded
+ 9000: ffffffff -> {'raw': 'ffffffff'}
+
+The Routing Indicator is a four-byte file but the actual Routing
+Indicator goes into bytes 0 and 1 (the other bytes are reserved). To set
+the Routing Indicator to 0x71:
+
+::
+
+ pySIM-shell (MF/ADF.USIM/DF.5GS/EF.Routing_Indicator)> update_binary 0071ffff
+
+(the encoding might be different, see `this
+comment <https://gist.github.com/mrlnc/01d6300f1904f154d969ff205136b753?permalink_comment_id=4050795#gistcomment-4050795>`__)
+You can also set the routing indicator to **0x0**, which is *valid* and
+means “routing indicator not specified”, leaving it to the modem.
+
+USIM Service Table
+------------------
+
+First, check out the USIM Service Table (UST):
+
+::
+
+ pySIM-shell (MF)> select MF
+ pySIM-shell (MF)> select ADF.USIM
+ pySIM-shell (MF/ADF.USIM)> select EF.UST
+ pySIM-shell (MF/ADF.USIM/EF.UST)> read_binary_decoded
+ 9000: beff9f9de73e0408400170730000002e00000000 -> [2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 25, 27, 28, 29, 33, 34, 35, 38, 39, 42, 43, 44, 45, 46, 51, 60, 71, 73, 85, 86, 87, 89, 90, 93, 94, 95, 122, 123, 124, 126]
+
+.. list-table:: From TS31.102
+ :widths: 15 40
+ :header-rows: 1
+
+ * - Service No.
+ - Description
+ * - 122
+ - 5GS Mobility Management Information
+ * - 123
+ - 5G Security Parameters
+ * - 124
+ - Subscription identifier privacy support
+ * - 125
+ - SUCI calculation by the USIM
+ * - 126
+ - UAC Access Identities support
+ * - 129
+ - 5GS Operator PLMN List
+
+If you’d like to enable/disable any UST service:
+
+::
+
+ pySIM-shell (MF/ADF.USIM/EF.UST)> ust_service_deactivate 124
+ pySIM-shell (MF/ADF.USIM/EF.UST)> ust_service_activate 124
+ pySIM-shell (MF/ADF.USIM/EF.UST)> ust_service_deactivate 125
+
+In this case, UST Service 124 is already enabled and you’re good to go. The
+sysmoISIM-SJA2 does not support on-SIM calculation, so service 125 must
+be disabled.
+
+USIM Error with 5G and sysmoISIM
+--------------------------------
+
+sysmoISIMs come 5GS-enabled. By default however, the configuration stored
+in the card file-system is **not valid** for 5G networks: Service 124 is enabled,
+but EF.SUCI_Calc_Info and EF.Routing_Indicator are empty files (hence
+do not contain valid data).
+
+At least for Qualcomm’s X55 modem, this results in an USIM error and the
+whole modem shutting 5G down. If you don’t need SUCI concealment but the
+smartphone refuses to connect to any 5G network, try to disable the UST
+service 124.