Sim elementary file structure

Subordinate to each of the DFs are supporting EFs, which contain the actual data. All the files have headers, but only EFs contain data. The first byte of every header identifies the file type and the header contains the information related to the structure of the files.

The body of an EF contains information related to the application. Files can be either administrative- or application-specific and access to stored data is controlled by the operating system. SIM cards have built-in security features. 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:. The SIM operating system controls access to an element of the file system based on its access condition and the type of action being attempted.

The operating system allows only limited number of attempts, usually three, to enter the correct CHV before further attempts are blocked.

The SIM card contains sensitive information about the subscriber. Data such as contact lists and messages can be stored in SIM. SIM cards themselves contain a repository of data and information, some of which is listed below:.

It consists of an industry identifier prefix 89 for telecommunications , followed by a country code, an issuer identifier number, and an individual account identification number. One example of the interpretation of a hypothetical nineteen digit ICCID 89 10 1 is shown below. Issuer identification number IIN is variable in length up to a maximum of seven digits:. IMSI : The international mobile subscriber identityis a unique digit number provided to the subscriber.

An example of interpreting a hypothetical digit IMSI is shown below:. Messaging is a communication medium by which text is entered on one cell phone and delivered via the mobile phone network. The short message service contains texts and associated parameters for the message. Need an account? Click here to sign up. Download Free PDF.

Sim and usim filesystem: a forensics perspective Proceedings of the ACM symposium on …, Antonio Savoldi. A short summary of this paper. Sim and usim filesystem: a forensics perspective. The real tem of SIM and USIM cards, enlightening what the offi- news for the digital forensics research is to know what is cial standard reference does not say.

Further, some 29 files, of the standard reference elementary files illustrated practical examples regarding the data hiding procedure as a in ETSI [14]. Other similar tools, for example Dat- proof of concept will be analyzed and discussed. More information about mobile Keywords forensics tools can be found in [12].

Throughout the rest of the paper we devices. To copy otherwise, to 2. Fur- System , which increases, with respect to the GSM counter- thermore, subscribers could be registered to one or part, the bandwidth for data exchange. A record is a group of setting up the communication session, issues to the SIM, bytes that has a known coding: every record of the then waiting for the responses and, among these, only few same file represents the same kind of information.

Standard programs, like that developed by Shenoi[4], can Level Access conditions extract only the standard elementary files starting from the 0 ALWays selection rules defined in the reference standard [14].

This is important to un- current directory is selectable. Indeed, it has ent of the current selected element; been used only standard methods in order to extract digital data. SIM Memory Structure : The SIM memory structure is said to be consist of directories which are analogous to the directories of traditional hard disk drive. Master File — Master file is root of file system. It is analogous to root directory like in any of operating systems. It may or may not elementary files EF.

It may contain one or many dedicated files DF. Skip to content. Change Language. Related Articles. Table of Contents. Improve Article. Save Article. Like Article.

Last Updated : 11 Aug, Dedicated File — It is sub directory. It can be identified by two byte identifier.