The security of the block cipher used in the compression function of ARIRANG
which was one of the SHA-3 candidates
was revaluated.Based on a linear transformation of the master key and the all-one differential of the round function
a full 40-round related-key rectangle attack of the ARIRANG encryption mode was presented
which was the first cryptanalytic result of the ARIRANG encryption mode.The result shows that the ARIRANG encryption mode as a block cipher is not immune to the related-key rectangle attack.