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Systems Management
Published in Paul J. Fortier, Handbook of Local Area Network Software, 1991
If X = 10 is the plain text information, f(X) = 15020 is the cipher text. The calculation of f(X) is very straightforward. Given Equation (5) and f(X) = 15020, the value of X = 10 is not as easy to calculate. The type of one-way function often used in Public-Key cryptography is called a trapdoor function. A trapdoor function is a one-way function except that a secret means has been built into the function to allow easy deciphering. This information is very carefully hidden and without the secret key the cipher text cannot be deciphered.
IoT Blockchain Integration
Published in Mohiuddin Ahmed, Abu S. S. M. Barkat Ullah, Al-Sakib Khan Pathan, Security Analytics for the Internet of Everything, 2020
Kazım Rıfat Özyılmaz, Arda Yurdakul
The first notion of digital signature algorithms is attributed to Whitfield Diffie and Martin Hellman [36]. The underlying mechanism is a one-way trapdoor function which is easy to compute in one direction, but extremely difficult to calculate in the reverse direction. Soon after that, Ronald Rivest, Adi Shamir, and Len Adleman invented the RSA algorithm [37]. Other notable mentions on digital signatures are Lamport signatures [38] with non-reusable keys and Merkle trees [39], which are extensively used in blockchain systems for transaction verification.
Asymmetric encryption algorithm for colour images based on fractional Hartley transform
Published in Journal of Modern Optics, 2019
A. K. Yadav, Phool Singh, Indu Saini, Kehar Singh
Most of the asymmetric encryption studies after the Qin and Peng study (5) followed the one-way trapdoor function based on the phase-truncation approach in the input and the frequency planes, which makes the system nonlinear. Many of them considered double-image (8–12) and multiple-image (13–20) encryption. Others have presented encryption schemes for colour images (21–33). Wang and Zhao (34) developed an iteration-based special attack for which the asymmetric cryptosystem based on the phase-truncated Fourier domain is vulnerable. Their special attack method is a two-step iterative algorithm which is based on amplitude retrieval approach. They and many others attempted improvements in asymmetric cryptosystems to endure the special attack (9, 35).
Phase-only asymmetric optical cryptosystem based on random modulus decomposition
Published in Journal of Modern Optics, 2018
Hongfeng Xu, Wenhui Xu, Shuaihua Wang, Shaofan Wu
It should be noted that the proposed cryptosystem can greatly enhance the security of the asymmetric optical cryptosystem. Firstly, the capacity to resist various attacks can be greatly improved. On the one hand, the proposed cryptosystem retains the advantages of one-way trapdoor function introduced by RMD. The information of original image is randomly encrypted into several complex-valued masks P1, and , different ciphertexts correspond to different private keys, which make it powerfully defend the attacks that symmetric DRPE cryptosystem is vulnerable to, such as known-plaintext, chosen-ciphertext and chosen-plaintext attacks (38–42). In addition, the amplitude of the ciphertext is different from that of the private key , which can remove the constraint brought by the ciphertext in the attack of iterative algorithm. On the other hand, the applying of phase encoding can remove the constraint generated by a public key. The public key is used to scramble the original image in the input plane of the encryption process. As a result, the constraints used in iterative attack can be thoroughly removed by the combination of phase encoding and RMD.
A remote sensing encrypted data search method based on a novel double-chain
Published in Connection Science, 2023
Xixi Yan, Pei Yin, Yongli Tang, Suwei Feng
Time overhead: (1) Search overhead. From Table 2, it can be seen the search overhead of the proposed scheme is much smaller than that of Bost’s scheme and Chen’s scheme, and the same as that of Liu’s scheme. However, the time of Liu’s scheme only spends on searching a single keyword, while our scheme takes the same amount of time to finish a multi-keyword search. The search cost of Li’s scheme is associated with the number of query keywords, which is far smaller than the number of all keywords, but it has to traverse the keyword index for every query keyword, which requires hash function operations and modulo exponentiation operations that is very time-consuming. The required search time increases linearly with the number of query keywords. During the search process, the proposed scheme traverses the keyword nodes in KIC and retrieves information on the nodes that satisfy the query keywords, which does not require additional modulo exponentiation operations compared to Li’s scheme. (2) Update overhead. Bost’s scheme requires trapdoor function operation for all keywords in an index, while the other schemes are all concerned with the average number of keywords contained in a file, so the updating overhead is much more efficient than Bost’s scheme. Chen’s scheme is similar to Liu’s scheme, which performs a hash operation for each update keyword and then generates the corresponding update information for each update keyword, but Liu’s scheme, which requires more hash operations and addresses fetching operations, requires relatively more time overhead. Li’s scheme requires pseudo-random function operation, hash function operation and modulo exponentiation operation for each update keyword. The proposed scheme performs symmetric encryption and HMAC operations for each update keyword while hashing the user’s identity and calculating the address of the KIC.