Why we use Mix Columns and Shift Rows in AES? FOr example, if i want implement an AES algorithm without Mix Columns and Shift Rows what is the difference in the ciphertext?
Without Mix Columns, every byte of the ciphertext would not depend on every byte of the plaintext, but only on the one byte at the same position. This would fully break AES, because we don't have an avalanche effect on the whole text anymore.
Without the Row shifting, every column of plaintext would only affect the same column of the ciphertext. This would break AES, too.
The question "Consequences of AES without any one of its operations" has some similarities with your question.