SIM: Subscriber Identity Module Part 1

SIM: Subscriber Identity Module Part 1.

Physical attributes:-

SIM cards are available in two standard sizes. The first and the oldest ones are the size of a credit card (85.60 mm × 53.98 mm x 0.76 mm). The newer, more popular miniature-version has a width of 25 mm, a height of 15 mm, and a thickness of 0.76 mm. However most SIM cards are supplied as a full-sized card with the smaller card held in place by a few plastic links which can be easily broken off to be used in a phone that uses the smaller SIM.

Older SIM Card:-



Current/Newer SIM’s:-



Every mobile subscriber (MS)/user is issued with a smart card called a Subscriber Identity Module (SIM) which contains a 19-digit code either printed or embossed on the surface of the SIM card

The SIM provides a 19-digit code printed on the surface which also serves as a physical evidence, which consists namely of the following:-Name of the Network Provider, Unique ID Number, Country code and Month and the year of Manufacturing.

Example:- 8991900200xxxxx9770 see attached Image above

here, 89-is the Telecom ID, 91– is our Country code for India, 90– refers to Network Code, and 0200 refers to Month and the year of Manufacturing. which i am still in doubt, as i have purchased this SIM very recently.

What is SIM:-

It is part of a removable Smart Card Integrated Circuit Card, also known as SIM Cards, for mobile cellular telephony devices such as mobile computers and mobile phones.


As SIM it is basically a smart card with it’s own CPU processor,

Also NVRAM, Non-volatile memory The Processor is used for providing access to the data and security. The GSM standard 11.11 specifies the physical and logical properties of access mechanism for the SIM.

To access the data stored on the SIM one needs to have access to a Standard smart card reader SIM access Software, since the Data stored is in binary files. And the OS and Filesystem varies by vendor to vendor.


SIM operating systems come in two main types: Native Sim Card and Java based SIM Card.

Native SIMs are based on proprietary, vendor specific software

Java Card SIMs are based on standards, particularly Java Card which is a subset of the Java programming language specifically embedded devices. Java Card allows the SIM to contain programs that are hardware independent and interoperable.

Security In SIM :-

Every SIM can be protected by a Personal Identification Number (PIN) which is set at the time of manufacturing, and can be changed by the the user /MS

It typically provides a password or a Four digit code

It provides Usually 3 attempts before phone is blocked

Bypassing the PIN requires the Pin Unblocking Key (PUK)

A PUK unlock code is a 8 digit code, again set by manufacturer

Maximum 10 attempts before phone is permanently blocked.

Next in my SIM: Subscriber Identity Module Part 2, we will continue with some more details and insight into how SIM card can provide a lot more details in any given Mobile Forensics case to be used as an Evidence.


Nitin Kushwaha

Categories: DigitalForensics, GSM, Mobile Forensics, MyOwn | Tags: , , , , , , , , , , , | Leave a comment

Post navigation

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: