Please use Matlab

Given a piece of ciphertext generated with Vigenere cipher, find the encryption keyword and recover the corresponding plaintext. (Programming required) Use Kerckhoffs method to find the key length and show the numbers of coincidences for displacement of range 2 to 30. (Programming required) Find the keyword. (Programming required) Recover the plaintext.

ciphertext = ECDAAMRGDNXQQHBCRRPVQUHAEYAHKZWLGWEWDIEPUSCHYYJHDRWVRWEOAHDRWVUDGBRQKTXVNAZOVRKADXBKJGUCPUOBHDRBZOJVCOIPGRRPETQRFKSDUSPJYJOOJRVHPVXTHKAMUOLGOEJEVDUSDBEFSEACBVKJRVHPVXTHKAKARDVCPCICKAWKAGRFAJKYYEAQNHWTYBRLNMRHKZWLGPNBGSZVXCINFEVHWGYAQANXQKWFSAHEZOGCOROGVAZDHFJGRRQKEXRFKSDUSOGBRSPUSFJETYECQFCGFEQOFGKBXRBWOVRRDVWGCCNSAILBXGVAZKARXLDUSPVWRVAVXUWOGEEBNRKPVAQDUSYBBASNGRRREFDNBYRLRHSROAHDRWJOOFOAGEOVLZAFCRBAQDUSOZKYZINISOEECGFARDFKAEOPCICKEOPVFRZUQOFSNGOQOJQRRXQQQRREGGVGAGYPCJGOAHDVWFSHSGVHDXORDEAQGVAZSAGETRGHDRCCCNGGNGWAOJCJRDBVEZDUCQTRSOIVVVONJSGVPUOGSYUXVQWYSGWAFPECINMBINFOBTJBFRZNRKQWJTRRVWQXRJAELRTKEONHPRWCHAQDBTKYVBKWAIBBANXQWPNZCSWEOQHKUSZOPBXPSPUKGWJNMGIWYZEOYGSPSPUOCFKPORREAQJOOSBNICUDJWPUNVTBVMHZPVOFGQCZBGEAQSCNVXFHWAMRHDNDGVALCUCQYNFIZQOAZUUKVZWGKKWEALBCGFIBIOVWCZUYONDPVXGCWAYGVAEZECIVCRRPUOQFEIOEOOBFRFAVQACNVDFAKQOEBADEVJWYOAHWANGVAEOLCQJOESEAKPHQNVSOYGDBAILPBFAFKJHDNDVHSNCRLPEOZSHLVVYAYIGVAEOJCQYNOSJBCRQKANGOTVDUSNRPBFAUOJCQYNUORRDBFQAGUOPUKCDAAOQWJNMGIWYPNQPGYNMKHXTAWAGUCNNXVBYR