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Cryptographic Attacks, Impacts and Countermeasures
Published in Mohiuddin Ahmed, Abu S. S. M. Barkat Ullah, Al-Sakib Khan Pathan, Security Analytics for the Internet of Everything, 2020
Hazaa Al Fahdi, Mohiuddin Ahmed
A brute force attack is one of the techniques used to reveal an important data for a specific target such as password of a system, encryption keys of different types of encryption algorithms, and SSH logins. According to researchers, the brute force is used against encryption algorithm. For example, the brute force attack has been approved against the DES due to its key length of 56 bits. Thus, the attacker can apply the attack to obtain encrypted data within a few hours [5]. Furthermore, the brute force attack depends on a specific wordlist or an intelligent database, which is used to detect the algorithm key or password of the target. In spite of brute force useful attack, it is limited to short keys. For example, the AES has different key lengths of 128, 192, or 256 bits. Therefore, the brute force attack would take a long time to attack 128 bits of AES key [8].
Security for Networked A/V Systems
Published in Al Kovalick, Video Systems in an IT Environment, 2013
The Data Encryption Standard (DES) was developed in the 1970s by IBM for the U.S. government. This was the first “data mangler” to find wide acceptance; it was free of licensing fees, simple to implement in hardware, well documented, and fast. It is a symmetrical design; i.e., the same algorithm is used to decrypt as is to encrypt. Considering the amount of data morphing that DES does, this is an amazing achievement. The basic idea is shown in Figure 8.11. A message (parsed into 64-bit chunks or blocks) enters at the left side, is permuted by the initial permutation (IP, a remapping of the input bits), and then is mangled 16 times by a combination of the all important cycle operator (CO), followed by an XOR function. At the final stage, the output permutation (OP) exactly undoes the IP operation. The CO function is a relatively involved combination of a bit permutation followed by an XOR (with an internal key as its second input) followed by yet another substitution/permutation of bits. Each cycle makes the input message more and more unrecognizable. After so much data morphing, it is nearly impossible to examine the output and thereby determine its input without knowing the key.
Coding
Published in Goff Hill, The Cable and Telecommunications Professionals' Reference, 2012
Many cryptosystems have been developed, both by government agencies and commercial organizations. The first public standard system was the National Bureau of Standards Data Encryption Standard (DES), which is a block cipher with a 64-bit block length involving both substitution and transposition under the control of a 56-bit key (NBS, 1977). The original proposal was for a 64-bit key, and there are claims that DES keys have been broken in less than 24 hours and that DES is therefore too insecure for many applications. Triple DES, which consists of applying DES three times in succession, is believed to be secure in practice. DES has now been superseded by the Advanced Encryption Standard (AES), also known as Rijndael (NIST, 2001). AES has a fixed block size of 128 bits and a key size of 128, 192, or 256 bits.
Energy Efficient Lightweight Cryptography Algorithms for IoT Devices
Published in IETE Journal of Research, 2022
Tarun Kumar Goyal, Vineet Sahula, Deepak Kumawat
Advanced Encryption Standard (AES) is private key symmetric block cipher, which is faster and stronger than triple DES. In AES 128 Bit plain text converts into 128-bit cipher text with the help of 128 bit, 192 bit, and 256 bit keys. It is shown in Figure 2. To increase the complexity, its operation repeated for round of 10, 12, and 14 (). In every round requires four-word byte so total requirement for 128 bit size. First four word is the key and then they are expanded to calculate remaining 40 words for 10 rounds. This technique is called as key expansion. Each round includes Sub Bytes, Shift rows, Mix column, add round key, and last round is slightly different in which mix column is not present.
Efficiency Analysis of Cryptographic Algorithms for Image Data Security at Cloud Environment
Published in IETE Journal of Research, 2021
DES is developed in early 1970s at IBM and submitted to NBS to check the strength and security of the DES algorithm. DES is one of the landmarks in cryptographic algorithms. DES works based on Feistel cipher structure. DES is a symmetric cipher algorithm and uses the block cipher method for encryption and decryption [15]. The algorithm divides the plaintext into 64 bits blocks and 56-bits key is used to encrypt this 64-bit plaintext. The plain text block is divided into two halves, right and left. DES performs substitution and permutation on the plaintext using S box and P box. After substitution and permutation, an XOR operation performs to obtain the ciphertext. DES uses 16 rounds to obtain the final ciphertext. The DES can be cracked by brute force attacks [16]. There is much vulnerability in DES. M-DES is a modified version of DES which overcomes the vulnerability of DES such as Bit Error Rate (BER) caused by the avalanche effect. The algorithm can provide more security in wireless communication [17]. To protect DES from differential cryptanalysis attack, another modification has been done on the algorithm. As there is no Avalanche effect in M-DES, the BER [Bit Error Rate] should be much better than DES. Even though M-DES is better DES, it may be cracked by Men in Middle attack.
Practical overview of security issues in wireless sensor network applications
Published in International Journal of Computers and Applications, 2018
Harish Radhappa, Lei Pan, James Xi Zheng, Sheng Wen
Data encryption standard (DES) is a block cipher encryption technique. It contains a 64-bit block of data with key of 56 bits. The DES operates in three stages as mentioned below:Permutation on 64 bits generating the permutation input.Then followed by 16 rounds of iteration of function with random keys in every round, also with a pre-output.Final stage is the inverse permutation to obtain desired cipher block.The above steps show the encryption part of DES, and decryption part is a simple step where sub keys are reversed [34]. This technique would fail to provide optimal security for large applications, however, this would be fairly a feasible solution for medium-scale applications.