Authenticated encryption algorithms offer privacy, authentication, and data integrity, as well. In recent years, they have received special attention after the call for submissions of Competition for Authenticated Encryption: Security, Applicability, and Robustness (CAESAR) was published. The CAESAR goal is to generate a portfolio with recommendations of authenticated encryption algorithms for three different scenarios: Lightweight, high speed, and defense in deep. ELmD and COPA are two on-line authenticated encryption algorithms submitted to CAESAR; because of their similarities, they were merged as COLM during the third-round of CAESAR. COLM is a finalist in the use case 3 defense in depth. ELmD, COPA, and COLM are based on the ECB-mix-ECB structure, which is highly parallelizable and pipelineable. In this paper, we present optimized single-chip implementations of ELmD, COPA, and COLM using pipelining. For ELmD, we present implementations for eight combinations of its parameters set: For intermediate tags, fixed, variable tag length, and 10 and 6 AES rounds. COLM implementation is for variable tag length without intermediate tags. In the case of COPA, it does not have parameters set. The implementation results with a Xilinx Virtex 6 FPGA show that ELmD is the best option concerning area and speed for single-chip implementation. The area of COPA and COLM are 1.65 and 1.69 times ELmD's respectively. Regarding throughput, the range of our implementations goes from 33.34 Gbits/s for COLM to more than 35 Gbits/s for several versions of ELmD.

Several authentication protocols based on Physically Unclonable Functions (PUF) have been proposed to authenticate hardware devices. The preliminary steps of a PUF-based authentication protocol are to obtain and store on a remote server the reference device's secret identifier (known as the PUF response) by the manufacturer. This reference response is compared (accurately or with a small threshold) with the response given by the device during its normal use. However, the responses provided by a PUF are not fully stable over time and with environmental variations. Consequently, correction mechanisms have to be used to increase the PUF responses steadiness. In most of the proposed correction schemes in the literature, the correction mechanisms consume more area than the PUF; hence, these solutions are unfeasible for area cost restricted devices such as consumer items used for IoT applications. This article presents the use of a preliminary PUF noise characterization to perform an ultra-lightweight device authentication. The proposed PUF-based authentication protocol, called restoration protocol, adapts the reference PUF response (stored on the remote server) to the generated PUF response on the device without leaking any information to an adversary. In addition, the restoration protocol is implemented without the need of an expensive hardware system on the device side. The workload is performed only on the server side, which has more resources. The security analysis and the experimental validation results using real PUF responses obtained from TERO-PUF demonstrate the viability of the proposed protocol.