PwLMμ-TPE: A Visual-Usability and Privacy-Enhanced Thumbnail Preserving Encryption Scheme of Cloud Computing for Consumers

The speedy proliferation of cloud storage choices has prompted consumers to choose the cloud as a preferred platform for storing their collections of images. However, this trend also invokes fundamental security issues regarding image privacy and data breach scenarios. To address these issues, consumers have recently used miscellaneous traditional image encryption techniques, primarily concentrated on preventing unauthorized access to cloud-stored images to defend the privacy of the image data. Moreover, these methods prioritize privacy preservation, they often neglect the importance of maintaining the usability of the encrypted images; hence, a Thumbnail-preserving encryption (TPE) was newly raised to preserve the thumbnail unchanged post-encryption, thereby improving the prevailing usability of the stored image. Hence, legitimate consumers can conveniently preview and control the cipher image without decryption. PwLMμ-TPE scheme greatly decreases encryption durations by approximately 17 times compared to existing methods, achieving an expansion ratio of around 2.1 for encrypted images and 1 for decrypted images, while showing SSIM and PSNR values close to 0.9 and infinity, respectively, along with an NPCR value of nearly 99%. The scheme is favourably adequate to resist cryptographic attacks and ensures usability and privacy, making it particularly suitable for cloud-based applications.