Abstract
IoT and cloud computing are the novel fields that are rapidly progressing in the world of internet technology. A huge and massive amount of data are communicating via IoT and cloud devices. Along with the highly configured devices, IoT and cloud also empowered many resource-constrained devices to communicate and compute information through network. But the major problem that they face is how to provide data security through conventional cryptographic algorithms in such resource-constrained devices having smaller size, limited memory spaces, low computation capabilities, and limited power. In this scenario, the biggest driver towards the problem is lightweight cryptography (LWC). This chapter discusses thoroughly the LWC, different schemes of LWC, and cryptanalysis of different LWC schemes.
TopIntroduction
Internet of Things (IoT) are widely rambling day by day, in which cloud computing is providing an additional essence. Cloud in IoT act as a catalyst for the growth of future Internet Technologies. Everyday IoT devices deal with huge volume of data that need to be stored and processed. But due to its limited storage, resource constrained and shortage in communication, it always requires cloud for outsource storage and computation. This collaboration of cloud and IoT though provides a new dimension in the field of Internet technologies but give rise to a new series of challenges in the field of security and privacy.
Although many encryption schemes have already been encompassing to provide security and privacy to the data but the major problems that the cloud-IoT faces are with its resource constrained devices having smaller size, limited memory space, low computational capability and limited power. As per its requirement the cryptographic algorithms need to be lightweight in respect to storage, power consumption and computational capability. This leads to a new evolution in the field of cryptography and Lightweight Cryptography (LWC) arises as the solution. This chapter talks about this new trend of cryptography comprising the following sections.
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In the first section of the chapter is all about LWC and its need or more precisely its usefulness in Cloud based IoT.
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In the next section of the chapter several LWC Schemes that are currently in use for data encryption like LWC Stream Cipher, Block Cipher, Hash function, ECC have been discussed.
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The third section will describe the cryptanalysis of the above mentioned LWC Schemes.
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Lastly, the chapter focus towards the future aspects of LWC in Cloud based IoT.
TopLightweight Cryptography
Many encryption algorithms or cryptographic algorithms have been used so far to provide network security and privacy of data. The urge for new design criteria of cryptographic algorithm has arises due to the resource constrained Cloud-IoT devices. The most of these devices may have any one or more of the below mention requirements.
The conventional cryptographic algorithms found to be well suited for servers, computers and mobile devices but in case of low-end devices used in Cloud-IoT like RFID tags, Sensor nodes, embedded system, etc. they failed to fulfil their requirements. Thus, a new branch of cryptography has introduced, and termed as “Lightweight Cryptography (LWC)” that act as a solution for the resource constrained devices. There is no specified requirement in LWC but it tries to provide modest key size, smaller block size, lesser code, minimal clock cycle and a smaller number of iterations for encryption or decryption. Keeping in mind the trade-off between cost, security and performance in cryptographic algorithm, it has been attempted by the researchers to optimize the design goals while designing different LWC schemes.
TopLightweight Cryptographic Schemes
Lightweight cryptographic schemes are designed to optimize the cryptographic primitives such as cost, key size, block size, cycle rate and number of iterations. It is generally divided into three categories namely:
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Lightweight Symmetric Key Cryptography.
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Lightweight Asymmetric Key Cryptography.
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Lightweight Hash Function.
The Figure 1 represents the different division and sub-division of Lightweight cryptographic schemes.
Figure 1. Lightweight Cryptographic Schemes
Key Terms in this Chapter
Prime Factorization: The process for finding the prime number multiply together to get the given (original) number. As for example, let the given number be 21, then the prime factors of 21 are 3 & 7, as 3 & 7 are prime numbers.
Message Digest: A unique value generated by cryptographic hash function from data and unique symmetric key.
Key Length: The key size or key length represents the number of bits used in a cryptographic algorithm. It is an important factor to both symmetric and asymmetric algorithm.
Gate Equivalent (GE): A unit of measure that specify manufacturing-technology- independent complexity of digital circuits. In lightweight cryptography GE means physical area of a single NAND gate used in different CMOS technologies.
Initialization Vector (IV): A random number used to encrypt data along with a secret key. It is also called nonce – “number occurring once” that can be used only once in an encryption process.
Cryptanalysis: Is the study of investigating a cryptosystem to find out the weakness of the system through mathematical approach. The process is done by without knowing the structure of key.