In the most common form , binary digits are used -LRB- bits -RRB- , and the keystream is combined with the plaintext using the exclusive or operation -LRB- XOR -RRB- .

In the most common form , binary digits -LRB- bits -RRB- are used , and the keystream is combined with the plaintext using the exclusive or operation -LRB- XOR -RRB- .
