[caf]

XORing samples does not whiten the output. If we consider as an example the biased source producing independent & identically distributed (iid) bits, where each bit has a 0.7 probability of being 1 and 0.3 probability of being 0.

Your suggested whitener would produce 1-bits with probability 0.42 and 0-bits with probability 0.58 - still biased.

An example of a correct whitening algorithm for a source producing iid bits is this: Take two adjacent samples. If they are the same, throw them away; otherwise, take the first sample as the next output.