International Mobile Subscriber Identity Computer Science Essay

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SIM stands for subscriber identity module. It contains an integrated circuit on in. In integrated circuit international mobile subscriber identity (IMSI) is stored. It also stores a key related to IMSI. This key is used to authenticate subscriber. SIM is embedded into a SIM card. Till now there are four versions of SIM card full size SIM, Mini-SIM, Micro-SIM and Nano-SIM. Their integrated circuit is same only they are different in size. A SIM card contains following

Unique serial number (ICCID)

International mobile subscriber identity (IMSI)

Security and ciphering information

Information related to the local network

List of services

Personal identification number

Personal unblocking code


To make a duplicate copy of a SIM bought from any operator is called SIM cloning. During process of cloning identifying information of original SIM is transferred to another SIM. Secondary SIM can be used into another mobile device. All features from original SIM can be used on secondary SIM like making calls sending SMSs or surfing.

To make a successful clone of a given card we need to extract SIM card's IMSI (international mobile Subscriber identifier) and Authentication key (Ki). An IMSI is much easy to identify then finding the Ki. Different devices and software programs may be used to decrypt the Ki.

To do process of SIM cloning is illegal. In 1990 cellular service provider came to know that SIM cloning is possible. So they started to make security measures to stop process of SIM cloning. Now a day security measures are embedded into SIM. These security measures have made SIM cloning much more difficult. Because of security measures if a SIM card detect SIM cloning is performed SIM card can make it self non useable.

SIM cloning was much easier with older models of cell phones and still be technically done today, Successfully completing a cloning is very difficult for some and virtually impossible for most. Most of methods or devices those can be used to clone a SIM work with old models of SIM cards. Anti-tamper software are used in V2 3G SIM cards. This anti-tamper software has made SIM cloning impossible. Because of anti-temper software devices those were used in older time to clone SIM cards are useless.

SIM cloning can be interesting for an individual who wants to have two mobile phones with same number. If a person have two or more SIM cards he have to carry more than one mobile phones but with SIM cloning technique he can make clone of his all SIM cards and copy these SIM cards in single multi SIM. To clone own SIM card cannot result in any illegal activity. It can be for convenience. Mobile operator has only attached SIM cloning with illegal activity and hence they have made it difficult or impossible with anti-temper software.

SIM cloning is also used to unlock phones from any other provider to use it on u r home network. By using Ki from home network SIM and changing IMSI that phone expects. With this method phone thinks it have SIM from its native operator. This method is used to unlock iPhone.

Which cards can be cloned

All cards comes with first GSM algorithm Comp 128V1 can be cloned. As a thumb rule one can say that all cards those were issued before June 2002 can be cloned successfully. Because all those cards have Comp 128V1 algorithm. New cards with algorithm Comp 128 V2 and V3 cannot be cloned because it is not possible to read Key. It would be possible with original source code that we do not get. In many forums over internet it is discussed how to read key from Comp 128V2 and V3. But it is useless without a proper device.

How to do SIM cloning

To perform SIM cloning process we need following things

SIM card reader

Software to extract Ki and IMSI

Wafer card

Wafer card Programmer

Software to program wafer card


By using this process only COMP 128 V1 cards can be cloned. As mentioned earlier SIM cards with new algorithms cannot be cloned. If you have SIM card with COMP128V1 then it will be possible to clone it with this process. Many peoples are working on to crack new algorithms lets us hope new algorithms would be cracked soon.

Wafer cards

SIM cards those we buy from mobile operators are not programmable. To perform cloning process we need wafer cards. Wafer card comes in different categories. Three of them support GSM cloning. Out of these three cards Silver cards are used most. Silver card contains two electronic components PIC 16F876 and EEPROM 24C64. Wiring of these two components is show in following diagram.

SIM Cloning

Diagram1. Wafer card circuit diagram

As mentioned earlier to clone a SIM card we need IMSI and Ki from original SIM card. After extracting IMSI and Ki we need to copy them in to another SIM. SIM card from operators are not reprogrammable so we need wafer card. We can buy wafer card from online electronic store or may be in some shop.

SIM card reader

After getting wafer card we need SIM card reader. Required IMSI and Ki can be read from a card using a SIM card reader. There are many providers who are selling SIM card reader over internet. So SIM card reader can easily bought from online store. It can be USB connector or serial connector. Point to note when buying a SIM card reader is it should be compatible with software you are going to use to extract IMSI and Ki. It would be quite simple to buy SIM card reader from internet. But interesting would be to make one yourself. If someone is good working with electronic components. All components required making SIM card reader and circuit is given below.

Diagram 2 Sim card reader/writer schematic pinout

Software to extract Ki,IMSI and ICCID

Secret key is stored in SIM card and it is unique in each SIM card. To extract this key we need software. SIM card is place in SIM card reader and connected to computer. Woron Scan is software that can be used for scanning. Scanning time depends on some factors. These factors are software, SIM card and SIM card reader. Some cards takes only 30 minutes and some takes 24-36 hours. I have experiments with two SIM card readers. First one took 10 hours while second one took only 27 minutes. I believe second SIM card reader was with better quality hardware. In whole process of SIM cloning scanning is most time consuming process. Lots of Patience is required in this process. Very interesting feature of software named Woron Scan is it can detect weather it is a COMP 128 V1 SIM card or not. It helps to save and as well wasting original SIM card.

Another software that can be used to scan SIM card is called Sim easy. This software can also be used to scan Ki. It can also be used to manage contacts on SIM card.

Wafer card programmer

This programmer contains two programmers in one. First one is PIC programmer and second is EEPROM programmer. Here question is why two programmer are required answer is EEPROM of wafer card is programmed through PIC. Millenium 2000VX MAX is name of programmer that can be used to program wafer card.

Software to program wafer card

Wafer card can be made 10 in 1 SIM card or 16 in 1 SIM card. This means 10 cloned SIM can be stored into one 10 in 1 wafer card. Wafer card SIM will have a menu to choose between SIM's. to program wafer card we need two files one for PIC and one for EEPROM. SimEmu pr pic-ador are names of software those can be used to create hex file for PIC and EEPROM.

So now we have files ready to program into wafer mentioned earlier Millenium 2000VX can be used as programmer. Cardmaster is software that can be used with Millenium 2000VX.

Steps in short

Extracting the Ki and IMSI

Making the PIC and EEPROM files with SIM EMU configurator

Write the files to the SILVER WAFER card

Cutting the smart card into a Sim card and settings on the phone