Eric M. Smith

The hummingbird-2 lightweight authenticated encryption algorithm

Hummingbird-2 is an encryption algorithm with a 128-bit secret key and a 64-bit initialization vector. Hummingbird-2 optionally produces an authentication tag for each message processed. Like its predecessor Hummingbird-1, Hummingbird-2 has been targeted for low-end microcontrollers and for hardware implementation in lightweight devices such as RFID tags and wireless sensors. Compared to the previous version of the cipher, and in response to extensive analysis, the internal state has been increased to 128 bits and a flow of entropy from the state to the mixing function has been improved. In this paper we present the Hummingbird-2 algorithm, its design and security arguments, performance analysis on both software and hardware platforms, and timing analysis in relation to the ISO 18000-6C protocol.

Hummingbird: ultra-lightweight cryptography for resource-constrained devices

Due to the tight cost and constrained resources of high-volume consumer devices such as RFID tags, smart cards and wireless sensor nodes, it is desirable to employ lightweight and specialized cryptographic primitives for many security applications. Motivated by the design of the well-known Enigma machine, we present a novel ultra-lightweight cryptographic algorithm, referred to as Hummingbird, for resource-constrained devices in this paper. Hummingbird can provide the designed security with small block size and is resistant to the most common attacks such as linear and differential cryptanalysis. Furthermore, we also present efficient software implementation of Hummingbird on the 8-bit microcontroller ATmega128L from Atmel and the 16-bit microcontroller MSP430 from Texas Instruments, respectively. Our experimental results show that after a system initialization phase Hummingbird can achieve up to 147 and 4.7 times faster throughput for a size-optimized and a speed-optimized implementations, respectively, when compared to the state-of-the-art ultra-lightweight block cipher PRESENT [10] on the similar platforms.

Lightweight implementation of Hummingbird cryptographic algorithm on 4-bit microcontrollers

The Radio Frequency IDentification (RFID) technology provides an extensible, flexible and secure measure against product counterfeiting. However, due to the harsh cost and power constraints of RFID tags only dedicated cryptographic engines or low-power consumption microcontrollers can be integrated into tags to implement various security mechanisms. In this contribution, we investigate efficient implementation of an ultra-lightweight cryptographic algorithm Hummingbird[5] on a zero-power 4-bit MARC4 microcontroller from Atmel and compare the performance of Hummingbird to another ultra-lightweight block cipher PRESENT [4] on the same platform. Our experimental results show that after a system initialization phase Hummingbird can achieve about 58% faster throughput than the block cipher PRESENT on a 4-bit ATAM893-D microcontroller running at 16KHz, 500KHz and 2MHz, respectively. In particular, Hummingbird can process one data block with less than 12 ms under a typical low power configuration of 4-bit microcontrollers such as an 1.8V supply voltage and a 500KHz clock frequency.

A lightweight privacy-preserving mutual authentication protocol for RFID systems

In this paper we propose a novel privacy-preserving mutual authentication protocol for RFID systems using the recently proposed ultra-lightweight cryptographic algorithm Hummingbird-2. The new protocol is resistant to the most common attacks against the security and privacy of RFID systems. Furthermore, we also address efficient implementation of the proposed protocol on a batteryless, MSP430-based WISP tag, and investigate the performance of the key search process on a laptop. Our experimental results demonstrate that the Hummingbird-2 mutual authentication protocol provides a highly effective and efficient security and privacy solution for low-cost passive RFID tags.