This paper proposes a new involutive light-weight block cipher for resource-constraint environments called I-PRESENT TM . The design is based on the Present block cipher which is included inthe ISO/IEC 29192 standard on lightweight cryptography. The advantage of I-PRESENT TM is that the cipher is involutive such that the encryption circuit is identical to decryption. This is an advantage for environments which require the implementation of both circuits. The area requirement of I-PRESENT TM compares reasonably well with other similar ciphers such as PRINCE.

In this paper, state-of-the-art hardware implementations of MISTY1 block cipher are presented for areaconstrained wireless applications. The proposed MISTY1 architectures are characterized of highly optimized transformation functions i.e. FL and {FO-XOR-EKG}. The FL function re-utilizes logic AND-OR-XOR combinations whereas {FO-XOR-EKG} function explores 2 × compact design schemes for s-boxes implementation. A Combined Substitution Unit (CSU) and threshold area implementation are proposed for s-boxes based on Boolean reductions and Common Sub-expression Eliminations (CSEs). Besides, {FO-XOR-EKG} function is designed for manifold operations of FO / FI functions, 32-bit XOR operation and extended key generation thereby reducing the area. Hardware implementations on ASIC 180nm, 1.8V standard library cell realized compact and threshold MISTY1 designs constituting 1853 and 1546 NAND gates with throughput values of 41.6 Mbps and 4.72 Mbps respectively. A comprehensive comparison with existing cryptographic hardware designs establishes that the proposed MISTY1 architectures are the most area-efficient implementations till date.