Subscriber Identification Module Universal Subscriber Identification Module (USIM) and Universal Integrated Circuit Card (UICC) has replaced the SIM for most purposes may be and are often used interchangeably.
Subscriber Identification Module is also possible to store contacts on many Subscriber Identification Module cards.
Subscriber Identification Module cards are always used on GSM phones; for CDMA phones, they are only needed for newer LTE-capable handsets. Subscriber Identification Module cards can also be used in satellite phones.
Subscriber Identification Modules are designed to be transferable between different Mobile Devices.
Structure and File Systems#Subscriber Identification Module contains a processor and Operating System with persistent, electronic erasable, programmable read-only memory (EEPROM). Subscriber Identification Module also contains RAM and ROM.
The Hierarchical organized File System of a Subscriber Identification Module resides in persistent memory and stores data as names and phone number entries, text messages, and network service settings. The File System consists of three types of files:
- master file (MF)
- dedicated files
- DF (DCS1800)
- DF (GSM)
- DF (Telecom)
- elementary files - EF (ICCID)
- Personal Identification Number (PIN) for ordinary use,
- Personal Unblocking Code (PUK) for PIN unlocking.
SIM cards have built-in security features. The three file types, MF, DF, and EF, contain the security attributes. These security features filter every execution and allow only those with proper authorization to access the requested functionality. There are different levels of access conditions in DF and EF files. They are:
- Always—This condition allows to access files without any restrictions.
- Card holder verification 1 (CHV1)—This condition allows access to files after successful verification of the user’s PIN or if PIN verification is disabled.
- Card holder verification 2 (CHV2)—This condition allows access to files after successful verification of the user’s PIN2 or if the PIN2 verification is disabled.
- Administrative (ADM)—The card issuer who provides SIM to the subscriber can access only after prescribed requirements for administrative access are fulfilled.
- Never (NEV)—Access of the file over the SIM/ME interface is forbidden.
- Integrated Circuit Card Identifier (ICCID)
- International Mobile Subscriber Identity (IMSI)
- Service provider name (SPN)
- Mobile Country Code (MCC)
- Mobile Network Code (MNC)
- Mobile Subscriber Identification Number (MSIN)
- Mobile Station International Subscriber Directory Number (MSISDN)
- Abbreviated dialing numbers (ADN)
- Last dialed numbers (LDN)
- Short Message Service (SMS)
- Language preference (LP)
- Card holder verification (CHV1 and CHV2)
- Ciphering key (Kc)
- Ciphering key sequence number
- Emergency call code
- Fixed dialing numbers (FDN)
- Location Area Identity (LAI)
- Own dialing number
- Temporary Mobile Subscriber Identity (TMSI)
- Routing area identifier (RIA) network code
- Service dialing numbers (SDNs)
There have also been some Vulnerabilities
More Information#There might be more information for this subject on one of the following:
- Personal Unblocking Code
- SIM Swap
- Universal Mobile Telecommunications System
- Universal Subscriber Identification Module