Ucumberland Is Afill The Message In The 4x4 Matrixand Now Multiply Fill the message in the 4x4 matrix and now multiply by the AES MixColumns matrix in Galois Field. Remember the multiplication by 2 (MUL2) and 3 (MUL3) is performed using the lookup tables (MUL2 and MUL3) from Wikipedia. The message to encode is "UCUMBERLAND IS A+".
Paper For Above instruction The task involves encoding a message within a 4x4 matrix and then applying the AES MixColumns transformation in the context of Galois Field multiplication. Specifically, the message "UCUMBERLAND IS A+" needs to be arranged in a 4x4 byte matrix, then each column is transformed using the MixColumns matrix, which is a fixed matrix that performs a linear transformation on each column of the state in AES encryption. The transformation involves matrix multiplication with coefficients 2 and 3, expressed in GF(2^8), utilizing lookup tables MUL2 and MUL3 for efficiency. Introduction The AES (Advanced Encryption Standard) algorithm relies on several transformations, including SubBytes, ShiftRows, and MixColumns, to ensure the cipher's diffusion and security. The MixColumns step is a matrix multiplication over GF(2^8), mixing the bytes within each column of the matrix to obscure the original plaintext. This requires precise multiplication operations that are not straightforward in binary but are simplified by using lookup tables for multiplying by 2 and 3. The key is to correctly arrange the message into a 4x4 matrix, then perform the matrix multiplication, and finally interpret the results as the transformed state. Arranging the Message in the 4x4 Matrix The message "UCUMBERLAND IS A+" is 17 characters long, which exceeds the 16 bytes that fit into the 4x4 matrix. To fill the matrix, we take only the first 16 characters or incorporate padding. For simplicity, we will use the first 16 characters: U C U M