Talk:How bitcoin works

predict a cryptographic hash function

"Both the chaining, and the difficulty, are achieved via the SHA256 cryptographic hash function. The hash function essentially takes a block of data, and transforms it, in an effectively-impossible to reverse or to predict way, into a large integer. Making the slightest change to a block of data changes its hash unpredictably"

IMO the words "predict", "unpredictably" is misleading. The SHA256 cryptographic hash function is deterministic, so its result can be predicted by... the same function. :)

The key property is that the reverse function is costly, that's all.