Modification AES algorithm based on Extended Key and Plain Text

Abstract

Encryption is important for keep to confidential data. There are many of encryption algorithms to ensure the data, but should be the select the algorithm depended on the fast, strong and implementation. For that choose the advance encryption standard (AES) algorithm for encryption data because speed and easy implementation on small devices and some the feature for it. In this paper, a modification AES algorithm is presented within five proposals, the first modification is an extended plain text 4x4 for AES from 16 bytes to 64 bytes (8x8 array) this modified increase speed encryption, more security and increase complexity, second modification is an extended keys by change the key length that used from 176 bytes to 704 bytes for encryption and decryption process because change input state this involves key length, change key length is give more robust to encryption and more complexity, third modification is shift row stage by increment number of shift in each row and number of shift based on part of key, this modification because increase number of row and column in state input, fourth modification in mix column stage by change the static matrix to four separated matrix used for multiple input state this modified to increase the diffusion in data, and five modification in add round key stage by make it based on part of key to determent the number of sub key used with input state in XOR operation. Modifications process focused on the way increment the random sequence process inside algorithm by used some parts of key in development process.