Inviolable e-Question paper via QR code Watermarking and Visual Cryptography

Recurrent allegations of electronic question paper (e-QP) leakage and examination malpractices in educational institutions can be handled by the course faculty (F) securely transferring the e-QP data to a trustworthy collector (C). In this case, the data is a mix of run length encoding (RLE) for the binarized diagrams and tamper-resistant e-QP question text encrypted with a data modification technique. QR codes are being utilised to encode this combination for the two halves of the secret e-QP data. Digital watermarking is being used to embed the QR code for 1 e-QP chunk in the same for the second. Its n secret image shares are generated by F through deterministic XOR based (n, n)-Visual Cryptography (VC). These are submitted to n non-trusted parties which deliver their respective portions to C before the examination. C performs all the necessary operations to get back the full e-QP data in its raw form. The resulting image RLE in plaintext format is utilised to decompress the binarized pictures in e-QP. This paper, therefore, suggests and explores the usage of QR code watermarking and VC in the construction of a secure examination cryptosystem that is robust towards ordinary watermarking and other attacks.