A novel approach for the detection of OMR sheet tampering using encrypted QR code

In today's era, most of the competitive exams are accomplished with the use of OMR System i.e. Optical Mark Recognition System, but this technique is not fully secure in terms of data tampering. Now these days, tampering in the data of the OMR sheet is really common and affects top level competitive exams as well, e.g. Medical entrance etc. Tampering can be easily done by filling more responses in the OMR sheet by third person so that the examinee gets passed in the examination. This form of data tampering is not detected by existing OMR systems. In this paper, we introduce a new method to detect OMR sheet tampering in order to enhance the security of the OMR system, using encrypted QR codes. Examinee details and number of responses for the asked questions they filled are embedded in the encrypted QR code which is printed on the OMR sheet, so that any alteration in the OMR sheet details is well observed. In our method, ECC i.e. Elliptic Curve Cryptographic algorithm is employed to encipher the data and encrypted QR code is generated with this data and is printed on the OMR sheet. Encryption is performed at the coordinating institute (where the exam is being carried out) using the private key of coordinating institute and public key of exam-evaluation center (where evaluation and result generation is being carried out), and decryption is performed on exam-evaluation center using its own private key and public key of coordinating institute. Thus, original data are kept in the Encrypted QR Code which is decoded successfully only at the exam-evaluation center, so if any modification in the OMR sheet data or in the QR code itself is performed, it will be easily detected. In our experiment, we use Bouncy Castle library to implement ECC algorithm and ZXing library for the encoding and decoding of QR Codes. The experiment was conducted by taking two cases under observation, one for the OMR sheet containing tampered data and another for the OMR sheet having genuine data. The result shows that tampering in OMR sheet is successfully detected in the case of tampered OMR sheet and OMR sheet having genuine data is successfully verified.