For years Donald Knuth would write checks for $2.56 (one hexidecimal dollar) to anyone who found an error in one of his books. Needless to say, most of these checks went uncashed.

Unfortunately, he has decided to stop writing these checks. On his website he writes:

due to an unfixable security flaw in the way funds are now transferred electronically, worldwide, it is no longer safe to write personal checks.

One consequence of this debacle is, alas, that I can no longer write checks to reward the people who discover errors in my books. The system that I’ve been using has worked well for almost forty years; but recently I have had to close three checking accounts, and the criminal attacks on those accounts have caused significant grief to my bankers.

Instead of writing personal checks, I’ll write personal certificates of deposit to each awardee’s account at the Bank of San Serriffe, which is an offshore institution that has branches in Blefuscu and Elbonia on the planet Pincus.

He has an online list of the account balances at the Bank of San Serriffe.

[via God Plays Dice]