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chopchoptheory [2007/02/28 22:05]
darkaudax
chopchoptheory [2010/11/21 15:46] (current)
sleek typos
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.
  
chopchoptheory.txt ยท Last modified: 2010/11/21 15:46 by sleek