On relations between the basic notions of differential cryptanalysis

Some problems and inconsistencies in terminology related to the differential cryptanalysis of iterative block ciphers are considered. A set of definitions is suggested to solve these problems and to form a system of unified notions with no contradictions. By using the suggested definitions it is shown that the truncated characteristic is the most general notion: differential, truncated differential and characteristic are in fact particular cases of the truncated characteristic.