Cryptography is a method of securing text data, images and sound in order to secure its confidentiality and to minimize data stealing, attack, etc. The purpose of this study is to improve classic Vigenere cipher using bit circular shift on image encryption. This experiment uses both RGB and grayscale images as samples and shows that Vigenere cipher with bit circular shift has better performance when encrypting an image both visually and its randomness. It is obtained the MAE values of images of final encryption process are 81.702637 of RGB and 73.678756 of grayscale, and the final decryption process of 0 for both images. The randomness of images of the final encryption process is shown by its correlation coefficient values; it is 0.033857 of RGB and -0.058501 of grayscale.

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Minimum Wage is a minimum standard used by employers to provide wages to workers in their business environment. The national minimum wage is the average of the provincial minimum wage. There are many factors need to be considered to set a minimum wage. The aim of this study is to predict the minimum wage based on K-Mean clustering concept. The Minkowski Distance Weighting (MDW) then used to estimate a value at the observation point in a cluster by using a linear combination of values of all cluster members around observation point mapped in 3-dimensional Cartesian coordinates. The prediction result by MDW then optimized by Artificial Neural Network Back Propagation (ANN-BP) to obtain a smaller Mean Absolute Percentage Error (MAPE). The net structure which already trained then used to predict the minimum wage for next year.