{'fraction_non_alphanumeric': 0.015331010452961672, 'fraction_numerical': 0.0, 'mean_word_length': 5.298245614035087, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Orthogonally Interweaved Data Encryption Method for Screen to Camera Communication

Due to the broadcast nature of screen to camera communication (SCC) channels, SCC systems are under threat of eavesdropping. In this paper, we propose an orthogonally interweaved data encryption method to enhance the security of SCC systems. In our design, the secret key sequence is arrayed randomly and then used to generate an orthogonal key matrix by interweaving the rows in the identity matrix. By multiplying the key matrix, the user data bits are orthogonally interweaved. Then the key sequence is transmitted together with the user data after color-code modulation. The legitimate receiver's camera will subsequently demodulate the color code and extract the secret key sequence from the captured images. Finally, the orthogonal key matrix can be recovered based on this secret key sequence and its transpose can be directly used to decrypt the data bits. Under this method, even though the eavesdropper can capture the color coded image and demodulate the secret key sequence, it can not retrieve the transmitted data without the key matrix generation rule and the orthogonally interweaved data encryption scheme. Additionally, we analyze the theoretical information leakage of an SCC system encrypted using the proposed method. We perform simulations and illustrate that the proposed encryption method can achieve high security performance.