crypt is defined in assembly at s3 crypt.s and it would appear to use the same family of "cryptographic machine" as V6's crypt.c but it is even shorter and I can't tell if it has bounds checks or not — V6 limits output size to 512.

edit: if hash output length is variable it may be impossible to find a solution and then a side channel timing attack is probably the best option.

someone liked this but note that someone else had already determined it is limited to 64 bytes on a previous HN post so the overflow hack does work.