You know I m leaning more and more towards Roger s opinion here knowing what we know about the sources I think it s implied that IBM re invented DC but it s not unambiguous and it s really not such a critical point to this article I think we should just say that IBM was aware of differential cryptanalysis but didn t publish it at least in this article the proper place to get into this in detail would be in the Data Encryption Standard article or the differential cryptanalysis article juicetalk