 This weakness affected many disk encryption programs, including older versions of BestCrypt as well as the now-deprecated cryptoloop.To carry out the attack, a specially crafted plaintext file is created for encryption in the system under attack, to "NOP-out" the IV
such that the first ciphertext block in two or more sectors is identical.This requires that the input to the cipher (plaintext, formula_1, XOR initialisation vector, formula_2) for each block must be the same; i.e., formula_3.