chopchoptheory

# Differences

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 chopchoptheory [2007/02/28 22:05]darkaudax chopchoptheory [2010/11/21 15:46]sleek typos Both sides previous revision Previous revision 2010/11/21 15:46 sleek typos2007/02/28 22:05 darkaudax 2006/11/19 16:12 darkaudax 2010/11/21 15:46 sleek typos2007/02/28 22:05 darkaudax 2006/11/19 16:12 darkaudax Line 30: Line 30: * D0 to D4 remain the same. * D0 to D4 remain the same. * R5 = I3 + K5 = I3 + (D5+D5) + K5 = (I3+D5) + (D5+K5) = X + S5. * R5 = I3 + K5 = I3 + (D5+D5) + K5 = (I3+D5) + (D5+K5) = X + S5. - * R6 to R8 are computed by reversing one crc step based on the value of X. There'​s a correspondence among I2-I0 and J3-J1 because crc shiftes ​them back but D5 "​pushes"​ them forward again. They are not necessarily keeping the same values, but their difference depends only on X, which we have guessed. + * R6 to R8 are computed by reversing one crc step based on the value of X. There'​s a correspondence among I2-I0 and J3-J1 because crc shifts ​them back but D5 "​pushes"​ them forward again. They are not necessarily keeping the same values, but their difference depends only on X, which we have guessed. * J0 depends only on X. K9 = S9 + J0. We have guessed the last message byte and the last byte of keystream. * J0 depends only on X. K9 = S9 + J0. We have guessed the last message byte and the last byte of keystream.