We provide an overview of selected crypto-hardware devices, with a special reference to the lightweight electronic implementation of encryption/decryption schemes, hash functions, and true random number generators. In detail, we discuss the hardware implementation of the chief algorithms used in private-key cryptography, public-key cryptography, and hash functions, discussing some important security issues in electronic crypto-devices, related to side-channel attacks (SCAs), fault injection attacks, and the corresponding design countermeasures that can be taken. Finally, we present an overview about the hardware implementation of true random number generators, discussing the chief electronic sources of randomness and the types of post-processing techniques used to improve the statistical characteristics of the generated random sequences.A. J. ACOSTA, T. ADDABBO AND E. TENA-SÁNCHEZ resource consumption. This matter sets the point for the lightweight cryptography, that is, the subfield of cryptography aiming to provide solutions tailored for resource-constrained devices.According to Elsevier Scopus, the largest database of research peer-reviewed literature, since 2010, about 40k documents are returned if searching the keyword 'cryptography' [6]. A huge subset of these papers deals with conceptual, algorithmic, software, hardware solutions that may be taken into account in lightweight cryptography. In the face of such a vast literature, in this work, we provide a brief overview of selected crypto-hardware devices, with a special reference to the lightweight electronic implementation of encryption/decryption schemes, hash functions, and true random number generators (TRNGs).This paper is organized as in the following. In Section 2, we introduce some terminology and present an overview of the hardware implementation of the chief algorithms used in private-key cryptography, public-key cryptography (PKC), and hash functions. In Sections 3 and 4, we introduce some important security concerns about electronic crypto-devices, discussing SCAs, fault injection attacks, and the corresponding countermeasures that can be taken in the hardware design. Finally, Sections 5-8 are devised to provide an overview about the electronic implementation of TRNGs. In detail, in Sections 5 and 6, we discuss about security flaws, statistical defects, and predictability of TRNGs, presenting the chief sources of randomness used nowadays for their hardware implementation. In Sections 7 and 8, we discuss an overview of the different post-processing techniques aimed to improve the statistical characteristics of the generated random sequences and the evaluation methods used to assess the reliability of cryptographic TRNGs. Conclusion and References close the paper.
CRYPTOGRAPHIC ALGORITHMSCryptographic algorithms aim to convert secret data into an unreadable code for non authorized persons, protecting secret information from theft or alteration and also enabling authentication. For better understanding, in the next sections, we define the following...