There is NO restriction of one value to each keyword. It is a silly restriction and it is NOT a CIF requirement. Take a look at the gif etc standard. Choose one and everybody conforms to it. YOU would still have to strip it off.
Some vision is needed here.
But It's Not CIF Stick to CBF, anything containing CIF is not acceptable. David was just trying to point out what seemed to be a lack of understanding of what CIF was and how it worked. If you copy a binary file encoded on a little-endian architecture to one with a big endian architecture YOU are still going to have to do the translating. The reason why playboy pictures are viewable is strictly because the standard encodes a particular architecture into it, little-endian for gif for instance. This is a potential danger.