nGenerate mask
bits
nciphertext[i] =
cleartext[i]+stream(key,state)
ncleartext[i] =
ciphertext[i]-stream(key,state)
nCipher produces a
sequence of bits that is added to the cleartext
to produce ciphertext
nReceiver can generate the same sequence and subtract from ciphertext to recover cleartext
nMust never re-use
same part of stream
nEach bit is
encrypted independently
n