I have a cipher-text in binary, I know the beginning of the plain-text. I know that it is encrypted using LFSR, and I know nothing else.
How can I attack, and decrypt it?
What I have tried;
I converted the beginning of my plain-text to binary, which had a length of 84. My ciphertext's length is 952. I've got the first 84 bits of my cipher-text, XOR'd it with the known part of plain-text in binary, assuming that this would give me the first 84 bits of my key-stream, which was not periodic.
After that, I have used the Berlekamp-Massey algorithm with that 84 bits of the key-stream, to find the smallest possible connection polynomial that could be used to get it. (I don't know if it was definitely the connection polynomial for my key-stream, knowing that the long gap is huge and the known keystream is not periodic, it probably is not)
I then tried some shenanigans but nothing worked, I couldn't take any further steps. I've tried using the known cipher-text as the initial sequence and the polynomial I've got from the BM algorithm as the connection polynomial to generate another key, but that neither worked for my known plain-text or the rest, therefore assuming this was not a correct method to continue.
What further steps can be taken to decrypt this cipher?