CLEFIA,a new 128-bit block cipher proposed by Sony Corporation,is increasingly attracting cryptanalysts’ attention.In this paper,we present two new impossible differential attacks on 13 rounds of CLEFIA-128.The proposed attacks utilize a variety of previously known techniques,in particular the hash table technique and redundancy in the key schedule of this block cipher.The first attack does not consider the whitening layers of CLEFIA,requires 2 109.5 chosen plaintexts,and has a running time equivalent to about 2 112.9 encryptions.The second attack preserves the whitening layers,requires 2 117.8 chosen plaintexts,and has a total time complexity equivalent to about 2 121.2 encryptions. CLEFIA, a new 128-bit block cipher proposed by Sony Corporation, is increasingly attracting cryptanalysts’ attention. This paper, we present two new impossible differential attacks on 13 rounds of CLEFIA-128. The proposed algorithms utilize a variety of previously known techniques , in particular the hash table technique and redundancy in the key schedule of this block cipher.The first attack does not consider the whitening layers of CLEFIA, requires 2 109.5 chosen plaintexts, and has a running time equivalent to about 2 112.9 encryptions.The second attack preserves the whitening layers, requires 2 117.8 chosen plaintexts, and has total time complexity equivalent to about 2 121.2 encryptions.