A NEW CONVERTIBLE AUTHENTICATED ENCRYPTION SCHEME BASED ON THE ELGAMAL CRYPTOSYSTEM

2009 ◽  
Vol 20 (02) ◽  
pp. 351-359 ◽  
Author(s):  
CHENG-CHI LEE ◽  
MIN-SHIANG HWANG ◽  
SHIANG-FENG TZENG
Keyword(s):  
Computational Complexity ◽  
Encryption Scheme ◽  
Authenticated Encryption ◽  
Elgamal Cryptosystem ◽  
Encryption Schemes

A convertible authenticated encryption scheme allows a designated receiver to retrieve an authenticated ciphertext and convert the authenticated ciphertext into an ordinary signature. The receiver can prove the dishonesty of the sender to anyone if the sender repudiates his/her signature. Recently, many researchers have proposed convertible authenticated encryption schemes based on cryptological algorithms. In this paper, the authors shall present a new convertible authenticated encryption scheme based on the ElGamal cryptosystem. The proposed scheme is more efficient than Wu-Hsu's scheme in terms of computational complexity.

scholarly journals Release of Unverified Plaintext: Tight Unified Model and Application to ANYDAE

2020 ◽  
pp. 119-146
Author(s):  
Donghoon Chang ◽  
Nilanjan Datta ◽  
Avijit Dutta ◽  
Bart Mennink ◽  
Mridul Nandi ◽  
...  
Keyword(s):  
Block Cipher ◽  
Block Size ◽  
Unified Model ◽  
Constant Time ◽  
Encryption Scheme ◽  
Security Model ◽  
Authenticated Encryption ◽  
Encryption Schemes ◽  
Plaintext Awareness ◽  
Mixing Functions

Authenticated encryption schemes are usually expected to offer confidentiality and authenticity. In case of release of unverified plaintext (RUP), an adversary gets separated access to the decryption and verification functionality, and has more power in breaking the scheme. Andreeva et al. (ASIACRYPT 2014) formalized RUP security using plaintext awareness, informally meaning that the decryption functionality gives no extra power in breaking confidentiality, and INT-RUP security, covering authenticity in case of RUP. We describe a single, unified model, called AERUP security, that ties together these notions: we prove that an authenticated encryption scheme is AERUP secure if and only if it is conventionally secure, plaintext aware, and INT-RUP secure. We next present ANYDAE, a generalization of SUNDAE of Banik et al. (ToSC 2018/3). ANYDAE is a lightweight deterministic scheme that is based on a block cipher with block size n and arbitrary mixing functions that all operate on an n-bit state. It is particularly efficient for short messages, it does not rely on a nonce, and it provides maximal robustness to a lack of secure state. Whereas SUNDAE is not secure under release of unverified plaintext (a fairly simple attack can be mounted in constant time), ANYDAE is. We make handy use of the AERUP security model to prove that ANYDAE achieves both conventional security as RUP security, provided that certain modest conditions on the mixing functions are met. We describe two simple instances, called MONDAE and TUESDAE, that conform to these conditions and that are competitive with SUNDAE, in terms of efficiency and optimality.

Text Encryption based on Huffman Coding and ElGamal Cryptosystem

2020 ◽  
Vol 14 ◽  
Author(s):  
Khoirom Motilal Singh ◽  
Laiphrakpam Dolendro Singh ◽  
Themrichon Tuithung
Keyword(s):  
Data Transfer ◽  
Huffman Coding ◽  
Large Integer ◽  
Text Data ◽  
Storage Devices ◽  
Scientific World ◽  
Elgamal Cryptosystem ◽  
Encryption Schemes ◽  
Transfer Operation ◽  
And Performance

Background: Data which are in the form of text, audio, image and video are used everywhere in our modern scientific world. These data are stored in physical storage, cloud storage and other storage devices. Some of it are very sensitive and requires efficient security while storing as well as in transmitting from the sender to the receiver. Objective: With the increase in data transfer operation, enough space is also required to store these data. Many researchers have been working to develop different encryption schemes, yet there exist many limitations in their works. There is always a need for encryption schemes with smaller cipher data, faster execution time and low computation cost. Methods: A text encryption based on Huffman coding and ElGamal cryptosystem is proposed. Initially, the text data is converted to its corresponding binary bits using Huffman coding. Next, the binary bits are grouped and again converted into large integer values which will be used as the input for the ElGamal cryptosystem. Results: Encryption and Decryption are successfully performed where the data size is reduced using Huffman coding and advance security with the smaller key size is provided by the ElGamal cryptosystem. Conclusion: Simulation results and performance analysis specifies that our encryption algorithm is better than the existing algorithms under consideration.

Improvement of Tseng et al.'s authenticated encryption scheme with message linkages

2005 ◽  
Vol 162 (3) ◽  
pp. 1475-1483 ◽  
Author(s):  
Zhang Zhang ◽  
Shunsuke Araki ◽  
Guozhen Xiao
Keyword(s):  
Encryption Scheme ◽  
Authenticated Encryption

scholarly journals Cryptanalysis of PMACx, PMAC2x, and SIVx

2017 ◽  
pp. 162-176
Author(s):  
Kazuhiko Minematsu ◽  
Tetsu Iwata
Keyword(s):  
Provable Security ◽  
Block Cipher ◽  
Query Complexity ◽  
Block Length ◽  
Encryption Scheme ◽  
Authenticated Encryption ◽  
Pseudorandom Functions ◽  
Tweakable Block Cipher ◽  
Deterministic Authenticated Encryption ◽  
Provably Secure

At CT-RSA 2017, List and Nandi proposed two variable input length pseudorandom functions (VI-PRFs) called PMACx and PMAC2x, and a deterministic authenticated encryption scheme called SIVx. These schemes use a tweakable block cipher (TBC) as the underlying primitive, and are provably secure up to the query complexity of 2n, where n denotes the block length of the TBC. In this paper, we falsify the provable security claims by presenting concrete attacks. We show that with the query complexity of O(2n/2), i.e., with the birthday complexity, PMACx, PMAC2x, and SIVx are all insecure.

Exploiting the Leakage: Analysis of Some Authenticated Encryption Schemes

2016 ◽  
pp. 383-401 ◽  
Author(s):  
Donghoon Chang ◽  
Amit Kumar Chauhan ◽  
Naina Gupta ◽  
Arpan Jati ◽  
Somitra Kumar Sanadhya
Keyword(s):  
Authenticated Encryption ◽  
Encryption Schemes
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