Editing SIM card (section)

=== ICCID ===
Each SIM is internationally identified by its '''integrated circuit card identifier''' ('''ICCID'''). Nowadays ICCID numbers are also used to identify eSIM profiles, not only physical SIM cards. ICCIDs are stored in the SIM cards and are also engraved or printed on the SIM card body during a process called personalisation.

The ICCID is defined by the ITU-T recommendation [[E.118]] as the ''primary account number''.<ref>ITU-T, ITU-T Recommendation [[E.118]], The international telecommunication charge card, [http://www.itu.int/rec/T-REC-E.118 Revision history] {{Webarchive|url=https://web.archive.org/web/20121017235304/http://www.itu.int/rec/T-REC-E.118 |date=17 October 2012 }}, [http://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-E.118-200605-I!!PDF-E&type=items Revision "05/2006"] </ref> Its layout is based on [[ISO/IEC 7812]]. According to E.118, the number can be up to 19 digits long, including a single check digit calculated using the [[Luhn algorithm]]. However, the GSM Phase 1<ref>ETSI, ETSI Recommendation GSM 11.11, Specifications of the SIM-ME Interface, [http://www.3gpp.org/ftp/Specs/archive/11_series/11.11/1111-3G0.ZIP Version 3.16.0] {{Webarchive|url=https://web.archive.org/web/20071127095112/http://www.3gpp.org/ftp/Specs/archive/11_series/11.11/1111-3g0.zip |date=27 November 2007 }}</ref> defined the ICCID length as an opaque data field, 10 octets (20 digits) in length, whose structure is specific to a [[mobile network operator]].

The number is composed of three subparts:
*Issuer identification number (IIN)
*Check digit
*Individual account identification
Their format is as follows.

'''Issuer identification number (IIN)'''

* Maximum of seven digits:
** Major industry identifier (MII), 2 fixed digits, '''89''' for telecommunication purposes.
** [[List of country calling codes|Country code]], 2 or 3 digits, as defined by [[ITU-T]] recommendation [[E.164]].
*** [[North American Numbering Plan|NANP]] countries, apart from Canada, use '''01''', i.e. prepending a zero to their common calling code +1
*** [[Canada]] uses '''302'''
*** [[Russia]] uses '''701''', i.e. appending 01 to its calling code +7
*** [[Kazakhstan]] uses '''997''', even though it shares the calling code +7 with Russia
** Issuer identifier, 1–4 digits.
** Often identical to the [[Mobile country code]] (MCC).<ref name=":5" />

'''Individual account identification'''
* Its length is variable, but every number under one IIN has the same length.
** Often identical to the [[Mobile identification number]] (MIN).<ref name="Chen" />

'''Check digit'''
* Single digit calculated from the other digits using the [[Luhn algorithm]].

With the GSM Phase 1 specification using 10 [[Octet (computing)|octets]] into which ICCID is stored as packed BCD{{clarify|date=February 2024}}, the data field has room for 20 digits with hexadecimal digit "F" being used as filler when necessary.  In practice, this means that on GSM  cards there are 20-digit (19+1) and 19-digit (18+1) ICCIDs in use, depending upon the issuer. However, a single issuer always uses the same size for its ICCIDs.

As required by E.118, the ITU-T updates a list of all current internationally assigned IIN codes in its Operational Bulletins which are published twice a month (the last as of January 2019 was No. 1163 from 1 January 2019).<ref>{{cite web|url=https://www.itu.int/pub/T-SP-OB.1163-2019|title=Operational Bulletin No. 1163 (1.I.2019)|website=www.itu.int|language=en-US|access-date=2019-01-05|archive-date=5 January 2019|archive-url=https://web.archive.org/web/20190105165046/https://www.itu.int/pub/T-SP-OB.1163-2019|url-status=live}}</ref> ITU-T also publishes complete lists: as of August 2023, the list issued on 1 December 2018 was current, having all issuer identifier numbers before 1 December 2018.<ref>{{cite web|url=https://www.itu.int/pub/T-SP-E.118-2018|title=List of issuer identifier numbers for the international telecommunication charge card (in accordance with Recommendation ITU-T E.118 (05/2006))|date=5 January 2015|website=International Telecommunication Union|access-date=4 January 2019|archive-date=5 January 2019|archive-url=https://web.archive.org/web/20190105060539/https://www.itu.int/pub/T-SP-E.118-2018|url-status=live}}</ref>