The Return of the Boomerang

The boomerang analysis, together with its offspring the amplified boomerang analysis and the rectangle analysis, are techniques that are widely used in the analysis of block ciphers. We give realistic examples which demonstrate that the boomerang analysis can commonly give probability values that are highly inaccurate. Thus any complexity estimates for the security of a block cipher based on the boomerang or rectangle analysis must be viewed extremely sceptically.