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ASIC-Based Mining System in Blockchain for IoT Environment to Increase Scalability and Security
Published in Rajdeep Chakraborty, Anupam Ghosh, Valentina Emilia Bălaş, Ahmed A Elngar, Blockchain, 2023
Bhaskar Dutta, Barnita Maity, Abhik Banerjee, Tamoghna Mandal
Mining ASIC technology advanced both in terms of manufacturing technology and in terms of design to achieve greater hash rate, lower power consumption, and lower cost. ASIC miners perform complex calculations, known as hashing. The technique of cryptographic hash is utilized to achieve this. Hash functions compress a string of arbitrary length to a string of fixed length. The purpose of a hash function is to produce a “fingerprint” of a file, message, or other blocks of data. A hash function must have the following requirements [11–13]:One way property: For any given value h, it is computationally infeasible to find x with H(x) = h.Weak collision resistance: For any given block x, it is computationally infeasible to find y with H(x) = H(y).String collision resistance: For any given block x, it is computationally infeasible to find x and y with H(x) = H(y)
Cryptographic Hash Functions and Attack Complexity Analysis
Published in Sarvesh Tanwar, Sumit Badotra, Ajay Rana, Machine Learning, Blockchain, and Cyber Security in Smart Environments, 2023
Amit Bairwa, Vineeta Soni, Prashant Hemrajani, Satpal Singh Kushwaha, Manoj Kumar Bohra
Collision resistance is the property of a hash function that makes it computationally infeasible to find two colliding inputs. Different hash functions can be compared based on their collision probability. This collision probability can be thought of as analogous to the birthday paradox. With the increase in the number of possible output combinations, the probability of hash collision decreases on the same number of hash computations or guesses by the attacker or any other person. For example, in an MD5, the hash output length is 128 bits, but in an SHA1 hash, the output length is 160 bits, which means the total possible combinations are more than MD5. Suppose an attacker can compute hashes. A hash collision would probably occur, which would be approximately 0.393 in the case of an MD5 hash function. In contrast, in the SHA1 hash function, the probability of hash collision would reduce to around 0 (Tables 11.1 and 11.2).
Message Authentication
Published in Khaleel Ahmad, M. N. Doja, Nur Izura Udzir, Manu Pratap Singh, Emerging Security Algorithms and Techniques, 2019
A hash function is a function which takes variable-length input of data and returns a fix-sized hash value. The hash generated has even distribution and is random. The advantage of hash functions is that upon a change in the input data, hash value changes which is used for message authentication. A cryptographic hash function is used for security purposes. Since the hash is a one-way function, some amount of data are modified. It cannot generate the pre-specified hash value, and hence it becomes important to create hash functions which are hard to find out (Holden, 2013). There are no two data sets which generate the same hash value unless they are exactly the same. Due to these benefits, hash functions are used to check the authenticity of the messages that is if the contents of the messages have been modified or not. In cryptographic hash function, padding of data input is done to a fixed-length integer and the padding contains the length of the actual message in bits (Hsieh et al., 1999). Both sender and the receiver calculate hash value through the hash function, if the values matched before and after sending, the message’s integrity is maintained otherwise, it has been tampered after sending (Figure 14.1).
Hybrid lightweight cryptography with attribute-based encryption standard for secure and scalable IoT system
Published in Connection Science, 2022
Mounika Jammula, Venkata Mani Vakamulla, Sai Krishna Kondoju
A symmetric key cypher is one in which an unvarying size block of plain text is processed via a changeable function with a key as a parameter to produce cypher text. The symmetric key cypher and stream cypher (Jammula et al., 2022) store a string of bits of plaintext with a stream of bits generated by a key when it is passed through a function, resulting in a bit string of cypher text. The hash function is a cryptographic primitive that takes a given sized block of plaintext and converts it into a unique string of bits using a one-way function. One-way functions are essential components of many tools used in contemporary cryptography. They are utilised in message authentication, digital signatures, and pseudorandom generators. Furthermore, a one-way hash function is built in such a way that identifying a text that hashes to a given value is problematic. The MAC system employs a technique that encrypts messages using session encryption and the delivered regular text communication. The information is next processed by the MAC method, which creates identification labels with a specified distance. The message's MAC is the consequence of the data processing. Message authentication codes (Kumar et al., 2022a) are cryptographic primitives that take a key and a lengthy string of bits from a message as input and output a unique shorter string of bits. It is also known as the keyed hash function.
Exploring the RFID mutual authentication domain
Published in International Journal of Computers and Applications, 2021
Syed Muhammad Mohsin, Imran Ali Khan, Syed Muhammad Abrar Akber, Shahaboddin Shamshirband, Anthony T. Chronopoulos
Data security and mutual authentication among tag–reader and reader-back-end database server are the major issues regarding the security of RFID systems. A hash function takes two or more characters called keys as its input and it maps this input to a hash value or a hash code that is smaller in length compared to the length of the input. In other words, hash value or hash code is a fixed size finger print of variable size input. Most commonly used hash functions produce output of size 160 bits to 512 bits that depends upon the applied hash function. A good and effective hash function should have strong collision resistance property, which means that no two inputs should result into similar hash code or hash value at the output. Traditional hash functions like SHA-1, SHA-2 and MD5 require a lot of resources for their operations. Resource constraint devices require lightweight hash-based solutions and these lightweight hash-based RFID solutions may be grouped into a single class. Any of the Hash functions of this class can be used to achieve the objective of mutual authentication, data privacy, location privacy (un-traceability), etc. in an RFID system. Few prominent hash-based mutual authentication protocols [25,61–64] are described below.
Development of an automated system model of information protection in the cross-border exchange
Published in Cogent Engineering, 2020
Begimbayeva Yenlik, Ussatova Оlga, Biyashev Rustem, Nyssanbayeva Saule
The software sends a request to the authorization server to generate a temporary password. This temporary password is generated on the server and displayed to the user in additional software on the smartphone. This temporary password has a short duration of 20 seconds. The temporary password is generated based on the result of the selected trigonometric function, which has a number of variable parameters. The trigonometric function is combined into a table, the dimension of 256 × 256 is a multiple of degree 2. The choice of this function and its initial parameters is based on the result of the hash function of the SHA256 standards (FIPS 140-2 Standard and self-Encryption Technology, 2018; National Institute of Standards and Technology (NIST), 2018; Two-factor authentication, 2019). This is a cryptographic hash function developed by the US National Security Agency (National Security Agency, 2018). The purpose of the hash function is the transformation (or hashing) of an arbitrary set of elements in the data into a fixed-length value. This value will characterize the set of source data without the possibility of extraction.