Partial Multimedia Encryption with Different Security Levels

This paper presents three multimedia encryption algorithms base on a new generalized P-gray code (GPGC) to protect the surveillance data in homeland security applications. The GPGC is a k-digital parametric sequence suitable for any base, n. It is also called the (n, k, p)-gray code where p is a parameter that allows the users to change the distance to yield different gray code sequences. The base n and parameter p as security keys have many options to make the encrypted multimedia difficult to decode. This allows the encrypted objects to be protected with high levels of security. The experimental results verify that the presented algorithms are lossless approaches and good at partial multimedia encryption. A method of measuring the percentage of image encryption is introduced and the measure results are also provided to quantify the encryption performance. Experiments demonstrate that the algorithms show good performance for the common attacks. Due to the low complexity of the algorithms, they are also suitable for real-time applications. The principles behind the presented solutions may be applied to various image, audio, and video systems.