A Low Cost Ultra Light-Weight Block Cipher

Objective of this chapter is to reduce the implementation cost of the S-Box of Ultra Light-weight Block Cipher (ULBC), and make it cheaper than the two popular block ciphers GIFT and PRESENT. After explicitly observing the design criteria of the above two block ciphers, we have proposed in this chapter a new S-box that would be useful for designing light-weight block ciphers. We have find out the longest integral distinguisher of ULBC satisfying a bit constant. As we know that appending some rounds after that, some keybits can be recovered. By using division property, we generate some linear inequalities to formulate MILP program. In eleven round no integral distinguisher will be seen in ULBC. In this design, we have also developed a new property like BOGI which would be extremely helpful in building light-weight block ciphers. Depending on this property we design permutation layer, such that no bad output will go bad input. ULBC is composed of a S-box, associated bit wiring and key schedule. In this chapter, we have produced some of cryptanalytic attacks to assure certain security level.