A simple and easy to implement method of data cryptography will be introduced. This method can be easily used to encrypt-decrypt digital images with any type and size, it can be used to treat gray images, color images and secret messages. The simplified encryption and decryption function will minimize the required time for cryptography and they will use a simple operation of pixels’ values rearrangement to apply encryption and decryption. The values rearrangement is to be applied using a generated index key. The index key is generated using the chaotic logistic key formed by running a chaotic logistic map model using a selected values of chaotic parameters. The proposed method will increase the level of image protection by using a private key which is capable to increase the key space to resist hacking attacks. The proposed method will be tested and implemented using various images, the obtained results will be analyzed to prove the quality, efficiency and sensitivity of the proposed method.