Image encryption differs from text encryption due to some intrinsic features of images, such ashigh volume ofdata, strong correlations among pixelsandhigh compressioncapability.Therefore, traditional cryptographic methods are not suitable for this purpose.Inrecentyears,encryptionalgorithmbased onchaos,have beensuggestednew solutionsto developsecureimageencryption techniques.Because this typeofencryptiondue to someproperty of chaotic systems, such as ergodicity, random-like behavior, and sensitivity to initial conditions, are useful in cryptography. Accordingly, we introduce and evaluate the security ofchaos-based image encryption schemes. In this thesis, we have dividedthechaos-based image encryption algorithms intoalgorithms based on logistic map, Arnold catmap, algorithms in time and frequency domains and algorithms on the bit-level.So first, properties of chaotic systems and expressing some feature of image that distinguish it from texthave been introduced.Then, according to the justify; LINE-HEIGHT: 115%; MARGIN: 0cm 0cm 0pt; unicode-bidi: embed; DIRECTION: ltr; mso-layout-grid-align: none" dir=ltr Keywords: Image encryption, Chaotic maps,Security analysis