in reply to What's your favourite method of untainting?
For those who are unaware, the untainting method described in the third option refers specifically to tainting behaviour for hash keys - That is, hash keys are not tainted, ever. From perlsec - Because taintedness is associated with each scalar value, some elements of an array or hash can be tainted and others not. The keys of a hash are never tainted.
perl -le "print unpack'N', pack'B32', '00000000000000000000001000000000'"