www.IJoFCS.org The International Journal of FORENSIC COMPUTER SCIENCE IJoFCS (2011) 1, 59-67 DOI: 10.5769/J201101004 or http://dx.doi.org/10.5769/J201101004 I. INTRODUCTION Geographical Positioning Systems (GPS) tech- nology has become prevalent in many areas of life and increasingly continues to become an important technological function in many elec- tronic devices. This technology is generally used to provide location awareness and in turn pro- vides particular user services. A similar technol- ogy (cell site analysis) has also existed in mobile phones, which indirectly allows such devices to be tracked to within 10m of their use at any given point in time. One of the more popular applications of GPS technology is in Satellite Navigation (SatNav) based systems wherein GPS systems interface with applications which guide travellers through a journey. Such systems take various forms, however the more popular are the built-in (factory-fit) systems and mobile devices. These technologies have played an important part in the investigation of incidents, particularly where tracking the location of individuals is a key factor. We refer to this area of investigation as geo-positional forensics. Research into geo-positional forensics can be divided into three categories: • Legal engineering • Operating system/application analysis • Physical extraction and data analysis Legal engineering is the process of ensuring that the investigation is conducted in a sound manner and where the process conducted and the Abstract - Geo-positional systems have gained in technological prominence over previous years. These systems provide location based information to applications which, in some cases, record geographic coordinates within Exif data in files. One such application of this is in the iPhone camera facility which records the location of an image. This information can be relied upon in an investigation. However, this study, shows that there are question marks over the accuracy and reliability of this data. In this study we demonstrate two methods wherein the geographic coordinates of a picture taken with an iPhone can be modified and therefore prove unreliable. Keywords - Geo-positional forensics; geo-tags; Exif data; GPS; Challenging the Reliability of iPhone Geo-tags Harjinder Singh Lallie (1) , David Benford (2) (1) International Digital Laboratory (WMG), University of Warwick, Coventry, CV4 7AL (1) h.s.lallie@warwick.ac.uk (2) Blackstage Forensics Limited, The Old Stable, Catton Hall, Catton, Derbyshire, DE12 8LN (2) david@blackstage-forensics.co.uk