Attacks on randomization - repeating the question

• An attack: asking the same question many times

• Can be thwarted by

  • never answering the same question twice, or
  • always answering it the same.

• Query repetition:

  • corresponds to an error-correcting code word
  • a a a a a a a
  • probability of error is monotonic decreasing with n for n-symbol code words
  • rate of code = 1/n

Notes: