The rapid growth of technology led the security of data becomes a very important issue, in particular data on medical field. Therefore the security of data need to be considered. This research will focus on the security of medical image. The appropriate technologies to increase the security of medical image is the image encryption. This research, applied a technique that can encrypt a medical image, it is SompdipDey Advanced Encryption Image Technique. This technique has three phases, namely

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... s Rotation and Reversal, Extended Hill Cipher and Modified MSA Randomization. This research was also conducted on a modification of the stage Extended Hill Cipher that produces a better result so that the security of medical data will be increased.