• takes two values (1,2,4,8 bytes), treats as sequence of bits
• performs logical XOR on each corresponding pair of bits
• result contains same number of bits as inputs

  00100111           XOR | 0  1
^ 11100011           ----|-----
  --------             0 | 0  1
  11000100             1 | 1  0

Used in e.g. generating random numbers, building adder circuits