7 shows the correlation distribution of two horizontally adjacent pixels in plainimage/cipherimage for the proposed ECBFSC.
To prove the robustness of the proposed ECBFSC, we will perform sensitivity analysis with respect to both key and plainimage.
This guarantees the security of the proposed ECBFSC against brute-force attacks to some extent.
A desirable property for the proposed ECBFSC is that it is highly sensitive to small change in the plainimage (single bit change in plainimage).
To test the influence of one-pixel change on the plainimage, encrypted by the proposed ECBFSC, two common measures may be used: Number of Pixels Change Rate (NPCR) and Unified Average Changing Intensity (UACI).
NPCR is obtained using the proposed ECBFSC and estimated to be over 99.
Generally, these obtained results for NPCR and UACI show that the proposed ECBFSC is very sensitive with respect plainimage (plainimages have only one pixel difference).
The simulator for the proposed ECBFSC is implemented using the compiler in Borland C++ Development Suite 5.
Table 3 summarizes the encryption/decryption speeds for the proposed ECBFSC on images of different sizes.
The robustness of the proposed ECBFSC is further reinforced by a feedback mechanism, which leads the cipher to a cyclic behavior so that the encryption of each plain pixel depends on the key, the value of the previous cipher pixel and the output of the logistic map.
According to the results of our security analysis, we conclude that the proposed ECBFSC is expected to be useful for real-time image encryption and transmission applications.