Research On Image Encryption Algorithm Based On Bit Scrambling

Image is a widely used information carrier that plays a crucial role in commercial,financial,military,and political fields.Therefore,image security protection has always been a hot issue.Traditional encryption algorithms have some drawbacks when applied to image encryption,and it is necessary to propose algorithms that are suitable for image encryption.i is a mainstream image encryption algorithm.Compared to traditional encryption algorithms,chaotic image encryption algorithm has the characteristics of high encryption efficiency,strong security,and ability to resist differential attacks.Therefore,it is necessary to deepen research on chaos image encryption technology.Chaotic image encryption technology usually uses chaotic sequences to perform scrambling and diffusion operations at the pixel level to fully confuse the image,while bit scrambling can achieve the effect of simultaneously scrambling the position of pixel points and changing the size of pixel values.This thesis will study a chaotic image encryption algorithm based on bit scrambling,and the research results are as follows:(1)A complete image encryption algorithm based on bit scrambling was designed on the basis of generalized Arnold transform,bit scrambling,and memristor chaos.The key system of this algorithm is a memristor chaotic system designed on the basis of generalized Memristor and generalized Moore Spiegel chaotic system.There are infinite unstable equilibrium points and coexistence Attractor in this system.Using this chaotic system can generate more complex pseudo-random sequences,which can ensure the full implementation of the scrambling process.Transforming the Arnold transform to obtain a bit scrambling method,which combines memristor chaos with Arnold based bit scrambling to design a complete algorithm with good image encryption performance.(2)Based on bit layering,Rubik’s cube transformation,and continuous XOR,a Gorder Rubik’s cube bit transformation was designed and implemented,and a complete image encryption algorithm based on bit scrambling was designed and implemented.The encryption algorithm first uses four improved one-dimensional logistic chaotic maps and adds an external key to generate a pseudo random sequence.Then,the image is filled and bit layered.Then,under the control of the pseudo random sequence,the Rubik’s cube is constructed and decomposed,followed by a G-order Rubik’s cube bit transformation.Finally,the bit is grouped and re merged to obtain the encrypted image.This thesis mainly designs two image encryption algorithms related to bit scrambling,namely the design and use of a memristor chaotic system as the key system and the combination of multiple discrete maps and the addition of external keys as the key system.Both image encryption algorithms have good image encryption effects,strong security,and high encryption efficiency.The two algorithms are suitable for different encryption scenarios,and the image encryption algorithm based on improved Arnold bit scrambling is more suitable for image encryption of various sizes of images,facing scenarios of shear noise attacks? The image encryption algorithm based on the improved Rubik’s cube bit scrambling is more suitable for the image encryption of square images,and faces severe scenarios such as Gaussian noise,Salt-and-pepper noise and statistical analysis attacks.