What is the EID and how to find it?

What is the EID

EID is the short form of eUICC-ID which is the eUICC IDentifier used in the context of Remote SIM Provisioning (RSP) and Management of the eUICC.
Its the unique HW identifier of an embedded Universal Integrated Circuit Card (eUICC).

Specifications related to the EID

For OPTIGA™ Connect IoT OC2321 being an eSIM M2M the GSMA Technical Specification SGP.02 defines the EID.

• SGP.02 - the Remote Provisioning Technical Specification for eSIM M2M - specifies the eUICC IDentifier (EID) as a 32-digit decimal value based upon ITU-T E.118.
  The EID begins with the digits '89'.
  

• SGP.22 - the Remote Provisioning Technical Specification for eSIM consumer - defines the EID by reference to SGP.02.
  

• SGP.29 defines the structure and assignment process for EIDs that begin with digits other than '89'.

Definition of the EID

The EID has a data length of 32 digits

Fig.: OPTIGA™ Connect IoT - EID (SGP.02)

The EID consists of

• two digits for the Major Industry Identifier (MII) defined by ISO/IEC 7812-1
  followed by a
  
• three-digit Country Code published by the ITU in its 'List of Recommendation' ITU-T E.164
  and a
  
• three-digit Issuer Identifier. The complete list of ITU-registered IINs is published periodically as an Annex to the ITU Operational Bulletin
  the remaining section dedicates
  
• 5 digits to Platform and OS Version information
  a
  
• five-digit Additional Issuer Information
  plus
  
• 12 digits of Indivdual Identification Number
  finally then a
  
• pair of Check Digits
  

ITU (International Telecommunication Union) is the central registration Authority for Issuer Identifier Numbers

The two Check Digits are calculated as follows:

1. Replace the two check digits by two digits of 0,
2. Using the resulting 32 digits as a decimal integer, compute the remainder of that number on division by 97
3. Subtract the remainder from 98, and use the decimal result for the two check digits,
   If the result is one digit long, its value shall be prefixed by one digit of 0.
   When stored as a byte string, the first digit shall be put into the highest four bits of the first byte
   

Where to find the EID

• The EID is printed on the eUICC package
  
• The EID is stored in the eUICC
  

The EID is stored within the ECASD entity of the eUICC and can be retrieved by the Device at any time using the standard GlobalPlatform GET DATA command by targeting the ECASD as specified in GlobalPlatform Card Specification as follows:

• Select the ECASD using the SELECT command with the AID value defined in ETSI TS 101 220
• Send a GET DATA command to the ECASD with the Data Object Tag '5A' to retrieve the EID.

Example: How to read out EID

EID Read out

One option to get the EID is to read it electronically by means of Command-APDUs (Application Protocol Data Unit)
via the ISO/IEC 7816-UART:

1) SELECT ECASD: AID = A0 00 00 05 59 10 10 FF FF FF FF 89 00 00 02 00
-> 00 A4 04 00 10 A0 00 00 05 59 10 10 FF FF FF FF 89 00 00 02 00 
<- 90 00

2) GET DATA Tag 5A, EID example= 89034011560010000000000000000121
-> 80 CA 00 5A 12
<- 5A 10 89 03 40 11 56 00 10 00 00 00 00 00 00 00 01 21 90 00

More info on AIDs related to Remote SIM Provisioning can be found [here]

EID Interpretation

Lets analyze the EID of an OPTIGA™ Connect IoT OC2321.

Fig.: OPTIGA™ Connect IoT - EID example

• MII (Major Industry Identifier): 89 = Assigned for Telecommunication purposes
  
• Country Code: 034 = Spain
  
• Issuer Identifier Number: 011 = Valid Soluciones Tecnológicas S.A.U. http://valid.com.es
  
• Platform and OS Version: 56001
  
• Additional Issuer Information: 00000
  
• Indivdual Identification Number: 000000000001
  
• Check Digits: 21