The published attack [1] used a more sophisticated pattern of compromised decimalization tables, recovering the PIN in an average of 15 instead of 32 attempts.

The published attack [1] used a more sophisticated pattern of compromised decimalization tables, recovering the PIN in an average of 15 instead of 32 attempts. The naive pattern I described will work, but the published attack is more than twice as efficient. Also, in the IBM 3624 + Offset PIN block algorithm, the offset is subtracted (digit by digit without carry/borrow) from the customer-entered PIN, rather than added. [2] My memory has faded a bit in the 12 years since I read the paper. [1] https://en.wikipedia.org/wiki/Decimalization_table_attack [2] https://en.wikipedia.org/wiki/Personal_identification_number#IBM_3624_.2B_offset_method