Symbian is an operating system (OS) targeted at mobile phones that offers a high-level of integration with communication and personal information management (PIM) functionality. Symbian OS combines middleware with wireless communications through an integrated mailbox and the integration of Java and PIM functionality (agenda and contacts). The Symbian OS is open for third-party development by independent software vendors, enterprise IT departments, network operators and Symbian OS licensees
The smartphone operating system Symbian OS is produced by the software developer and licensing company Symbian Ltd. Symbian Ltd was established in June 1998 and has its headquarters in Southwark, UK, and the current CEO is Nigel Clifford. Symbian was previously owned by Nokia, Ericsson, Sony Ericsson, Panasonic and Samsung, on the 24th of June 2008 however Nokia announced it would acquire Symbian Ltd. Now, on this day, Nokia is the one and only owner of Symbian.
Symbian OS offers a high level of integration with communication and personal information management (PIM) functionality. As a smart phone operating system, Symbian can provide many applications and services such as; navigation, games, music playback, associated libraries, etc. Symbian was designed for mobile devices from its earliest incarnation as EPOC32 in the Psion Series 5.
Symbian Platform Security Model
The Symbian security model can be broken down into three main modules:
1.Trusted computing base (TCB)
The trusted computing base holds a collection of software packages which are used touphold and enforce the latter two modules. The TCB consists of the kernel, the file systemand the software installer.
2.Data Caging
A feature called data caging is introduced to protect executables and data files of theapplications. Directories for applications are protected by the file system in a way that onlythe processes with the original application secure identifier (SID) can get access to them.
By caging processes, so that they can only access specific parts of the file system all of theusers’ private data can be kept safe and separated from the applications processes.
All information and application resources, regardless whether they are public or private should be protected from unauthorized access by data‐caging protected directories and thus limiting access rights.
3.Capabilities
Capabilities define what the application can and cannot do. These rights are defined onapplication installation and they cannot be altered later on. In a way the capability model isused to express how trustworthy an application is. Through another point of view it alsolimits the applications permissions.
If a process wants to accomplish some tasks it needs some capabilities in order to be able torun the task in question. To run these tasks, the application also requires permissions whichare defined by the applications signature.
Capabilities can be split into four groups:
•Open to all
Most of the APIs fall into this category – about 60%. This category contains the most basicservices to build applications which do not introduce security issues.
•Granted by the user at installation time
These are capabilities that the user can choose to grant at installation time. Duringinstallation time these are also known as blanket permissions and during run time they areknown as “single shot” permissions.
Secure identifier (SID) and Vendor identifier (VID)
SID’s and VID’s are employed by processes to determine if an application or a process can access its API. Starting from Symbian OS v9.x every executable needs to have a Secure Identifier (SID). The SID concept enables the platform security to protect APIs, limit access to APIs specific to applications and to protect access to file system areas on the phone that are used when upgrading content.
Signing an application
Through signing a tamper‐proof certificate is introduced to the application. The certificate consists of the following data: Applications origin, definitions for API access.
Very simple and straightforward applications can skip the signing process all together.
To circumvent capability checks, the developer can choose to ask the user to grant a blanket permission for the application during installation.
Alternatively the developer can ask the user for a “single shot” permission during runtime. For instance, the “single shot” permissions could be used to ask for the users permission to send a message.
Symbian Signed enables applications to use the Platform Security architecture and distinguishes between User System and Restricted Capabilities. The various signing options allow applications to request different Capabilities:
•User Capabilities are available through all signing options.
•All System Capabilities, including Restricted (as defined in the table below), are available through Open Signed (with a Publisher ID) and Certified Signed options.
•Express Signed does not allow access to Restricted Capabilities (CommDD, DiskAdmin,NetworkControl, and MultimediaDD).
•Symbian Signed refers to the most sensitive Capabilities, specifically All Files, DRM, andTCB, as Device Manufacturer Capabilities.
These are only available through the OpenSigned (with a Publisher ID) and Certified Signed options and require DeviceManufacturer approval.
Future Possibilities
The leading mobile OS
According to research firm The Diffusion Group, Symbian's still maintains the prominent position as the most used mobile OS, is still the most popular smartphone platfom. Followed by Linux and then Microsoft, Symbian had 51% market share of the mobile OS market at the end of 2005, down from 56% in 2004, Linux Came in second at 23%, which was double its 2004 share of 11.3%. Microsoft came in third upping its 2004 market share of 12.6% to 17%. Symbian OS is still the “leading figure” in the smartphones market and according to Gartner Symbian’s market share is still the majority with a trend to decline, Gartner blames I phone and Blackberry.
Although, expects Symbian to maintain its leading and says the Nokia‐owned OS accounted 47,1% of the sector’s total sales in 4Q08. Apple continues to redefine the definitions of what a mobile phone operating system is. Symbian remains by far the most popular OS on the market. New research from Gartner shows that for the fourth quarter of 2008 Symbian based smartphones accounted for 47.1% of the sector’s total sales, with 17.9m handsets sold. BlackBerry‐owning RIM was next in line with 19.5% followed by Microsoft Windows Mobile at 12.4 % Apple trailed with a 10.7% market share and Linux 8,4%.
When the fact that Apple is a single device vendor is considered, however, the numbers become all the more impressive for Apple – particularly considering that the numbers represent a 111.6 per cent year‐on‐year hike. Nokia, in contrast, suffered a 21.6% annual drop.
Nokia’s buying the rest of Symbian that it doesn’t already own, and will then create the Symbian Foundation, in collaboration with a number of other companies, and make Symbian royalty free and opensource.
Symbian will be available royalty‐free. Anybody that wants to use it in handsets, or have access to the complete code, will just have to join the Symbian Foundation for $1500 a year. That essentially erases Android’s price advantage, and could lead to a raft of Symbian‐based devices for the mid and low tier from OEM vendors.
This should significantly enhance the ability of the Symbian platform to support custom UIs. It will be a key area of competition for mobile Operative Systems, and the ability for manufacturers to create their own UI enhancements will be crucial.
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