International Association
for Cryptologic Research

In this paper we are proposing an ultra lightweight, a very compact block cipher ‘PICO’. PICO is a substitution and permutation based network, which operates on a 64 bit plain text and supports a key length of 128 bits. It has a VERY compact structure that requires GEs for a 128 bit key length. The PICO cipher uses strong bit permutation layer which only needs wires for implementation this reduces overall gate count. Its unique design helps to generate a large number of active S - boxes in fewer rounds which thwart the linear and differential attacks on the cipher. PICO shows good performance on both the hardware and the software platforms. PICO consumes only 2504 bytes of Flash memory which is less than ultra lightweight cipher PRESENT. PICO has a very strong Substitution layer(S- box) which not only makes the design robust but also introduces a great avalanche effect. PICO has strong and compact key scheduling which is motivated from latest NSA designed cipher SPECK. PICO consumes 28mW of dynamic power which is less than the PRESENT cipher (31mW). In this paper we have presented the security analysis of PICO and its performance as an ultra lightweight compact cipher. PICO resists linear, differential, biclique, zero correlation, meet in the middle and key related attacks.