The Return of the Cryptographic 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. Realistic examples are given 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.