IOSR Journal of Computer Engineering (IOSR-JCE) e-ISSN: 2278-0661,p-ISSN: 2278-8727, Volume 17, Issue 1, Ver. VI (Jan – Feb. 2015), PP 56-63 www.iosrjournals.org DOI: 10.9790/0661-17165663 www.iosrjournals.org 56 | Page A Location Dependent Cryptographic Approach Based on Target Coordinate & Distance Tolerant Key transfer for GPS mobile Receiver Sourish Mitra 1 , Avijit Chakraborty 2 , Arunabha Bhaumik 3 , Joy Dewanjee 4 , Mainak Maulik 5 1, 2, 3, 4, 5 (Department of Computer Science & Engineering, Gurunanak Institute of Technology, India) Abstract: Independent location based cryptography technique ensures that after transferring encrypted data from sending end ,decryption can takes place at anywhere from receiving point of view. But according to demand of mobile users if we want to ensures more security at the time of data transfer in mobile communication we need location dependency .It means ,when we encrypt a particular data packet at sending end and after transmitting that data to the receiver ,the receiver can be able to decrypt that packet only from a particular location (not from anywhere) specified by the sender by transferring location based coordinate target .In our proposed location based data encryption-decryption approach a target latitude/longitude coordinate is incorporated with a random key for data encryption. The receiver can only decrypt the cipher text when the coordinate acquired from GPS receiver is matched with target coordinate .The location of a receiver is difficult to exactly match with target coordinate .So we proposed a parameter distance tolerant(DT) in our proposed approach to increase its practicality. The security analysis shows that to probability to break our proposed algorithm is almost impossible since the length of the random key is adjustable. Keywords: Location dependency, latitude/longitude, GPS, Distance tolerant, Target coordinates. I. Introduction In location dependent cryptography method Sender can’t restrict the location of the receiver for data decryption .If the encryption algorithm can provide such it is useful for increasing the security of mobile data transmission in the future .Therefore we propose location coordinate based encryption decryption technique where latitude longitude coordinate as the key for data encryption. When a target coordinate is determined for data encryption, the cipher text can only be decrypted at the expected location .Since the GPS receiver is inaccurate and inconsistent depending on how many satellite signal received .It is difficult for receiver to decrypt the text at same location exactly matched with the target coordinate .It is impractical by using inaccurate GPS coordinate as key for data encryption. Concurrently DT (Distance Tolerant) is designed in our proposed method. Sender can also determine the DT and the receiver can decrypt the text within the range of DT. Fig. 1: Location Dependent Approach (Proposed) II. Related Work On 2003, Scott and Denning et al. proposed a data encryption algorithm by using the GPS, called Geo- Encryption. Geo-Encryption was based on the traditional encryption system and communication protocol. For