I am trying to figure out the process behind the Speck block cipher. I understand how XOR works (Exclusive-or) when you take 2 strings of bits and you want to XOR them together.
However, in the key schedule of the cipher, there is a point where XOR takes place but I don t understand what is being XORed.
For example, in the key schedule in the link, the result of the binary addition is being XOR d with 0?
Can someone explain what this means? Thanks.