Modifikasi enkripsi dan dekripsi AES menggunakan polybius chiper dalam pengamanan data
Data is a file that can be confidential so it requires a data security process to maintain confidentiality. Kripotgrrafi is a data security process that can be used based on the use of algorithms, one of which is AES. AES is a modern algorithm that can be modified to improve confusion and diffusion in cryptography. AES combination can be done using Polybius which has cryptographic diffusion properties. This study modified the AES using 6x6 and 10x10 polybius matrices that were performed on plaintext and plaintext and keys. Analysis was carried out based on the highest bit change rate found in modification II in the plaintext and 6x6 matrix keys, which amounted to 51.8% using the avalanche effect test. The results of the AE compared to the expected results using chi square with the modified AES results can increase the AE by 5% with the real level is 0,05 and the degree of freedom is 4 . Execution time was tested in this study with the results of the AES modification time longer than the standard AES because the complexity of the algorithm affects both encryption and decryption time.Abstract Data is a file that can be confidential so it requires a data security process to maintain confidentiality. Kripotgrrafi is a data security process that can be used based on the use of algorithms, one of which is AES. AES is a modern algorithm that can be modified to improve confusion and diffusion in cryptography. AES combination can be done using Polybius which has cryptographic diffusion properties. This study modified the AES using 6x6 and 10x10 polybius matrices that were performed on plaintext and plaintext and keys. Analysis was carried out based on the highest bit change rate found in modification II in the plaintext and 6x6 matrix keys, which amounted to 51.8% using the avalanche effect test. The results of the AE compared to the expected results using chi square with the modified AES results can increase the AE by 5% with the real level is 0,05 and the degree of freedom is 4 . Execution time was tested in this study with the results of the AES modification time longer than the standard AES because the complexity of the algorithm affects both encryption and decryption time.