On Shortening Ciphertexts: New Constructions for Compact Public Key and Stateful Encryption Schemes

2011 ◽  
pp. 302-318 ◽  
Author(s):  
Joonsang Baek ◽  
Cheng-Kang Chu ◽  
Jianying Zhou
Keyword(s):  
Public Key ◽  
Encryption Schemes

Public-Key Encryption

2017 ◽  
Author(s):  
Keith M. Martin
Keyword(s):  
Elliptic Curve ◽  
Public Key Cryptography ◽  
Public Key ◽  
Public Key Encryption ◽  
Hybrid Encryption ◽  
Public Key Cryptosystems ◽  
Encryption And Decryption ◽  
Encryption Schemes ◽  
Hard Problems ◽  
Set Up

In this chapter, we introduce public-key encryption. We first consider the motivation behind the concept of public-key cryptography and introduce the hard problems on which popular public-key encryption schemes are based. We then discuss two of the best-known public-key cryptosystems, RSA and ElGamal. For each of these public-key cryptosystems, we discuss how to set up key pairs and perform basic encryption and decryption. We also identify the basis for security for each of these cryptosystems. We then compare RSA, ElGamal, and elliptic-curve variants of ElGamal from the perspectives of performance and security. Finally, we look at how public-key encryption is used in practice, focusing on the popular use of hybrid encryption.

Public Key Broadcast Encryption Schemes With Shorter Transmissions

2008 ◽  
Vol 54 (3) ◽  
pp. 401-411 ◽  
Author(s):  
Jong Hwan Park ◽  
Hee Jean Kim ◽  
M.H. Sung ◽  
Dong Hoon Lee
Keyword(s):  
Public Key ◽  
Broadcast Encryption ◽  
Encryption Schemes

Public-Key Encryption In The Standard Model Against Strong Leakage Adversary

2020 ◽  
Vol 63 (12) ◽  
pp. 1904-1914
Author(s):  
Janaka Alawatugoda
Keyword(s):  
Standard Model ◽  
Building Blocks ◽  
Public Key ◽  
Log P ◽  
Encryption Scheme ◽  
Public Key Encryption ◽  
Security Parameter ◽  
The Standard Model ◽  
Encryption Schemes ◽  
Leakage Resilient

Abstract Over the years, security against adaptively chosen-ciphertext attacks (CCA2) is considered as the strongest security definition for public-key encryption schemes. With the uprise of side-channel attacks, new security definitions are proposed, addressing leakage of secret keys together with the standard CCA2 definition. Among the new security definitions, security against continuous and after-the-fact leakage-resilient CCA2 can be considered as the strongest security definition, which is called as security against (continuous) adaptively chosen-ciphertext leakage attacks (continuous CCLA2). In this paper, we present a construction of a public-key encryption scheme, namely LR-PKE, which satisfies the aforementioned security definition. The security of our public-key encryption scheme is proven in the standard model, under decision BDH assumption. Thus, we emphasize that our public-key encryption scheme LR-PKE is (continuous) CCLA2-secure in the standard model. For our construction of LR-PKE, we have used a strong one-time signature scheme and a leakage-resilient refreshing protocol as underlying building blocks. The leakage bound is $0.15n\log p -1$ bits per leakage query, for a security parameter $k$ and a statistical security parameter $n$, such that $\log p \geq k$ and $n$ is a function of $k$. It is possible to see that LR-PKE is efficient enough to be used for real-world usage.

scholarly journals Universal Hash Proofs and a Paradigm for Adaptive Chosen Ciphertext Secure Public-Key Encryption

2001 ◽  
Vol 8 (37) ◽  
Author(s):  
Ronald Cramer ◽  
Victor Shoup
Keyword(s):  
Special Kind ◽  
Public Key ◽  
Proof System ◽  
Reasonable Assumption ◽  
Encryption Scheme ◽  
Public Key Encryption ◽  
Proof Systems ◽  
Encryption Schemes ◽  
Hash Proof System ◽  
Chosen Ciphertext Attack

We present several new and fairly practical public-key encryption schemes and prove them secure against adaptive chosen ciphertext attack. One scheme is based on Paillier's Decision Composite Residuosity (DCR) assumption, while another is based in the classical Quadratic Residuosity (QR) assumption. The analysis is in the standard cryptographic model, i.e., the security of our schemes does not rely on the Random Oracle model.<br /> <br />We also introduce the notion of a universal hash proof system. Essentially, this is a special kind of non-interactive zero-knowledge proof system for an NP language. We do not show that universal hash proof systems exist for all NP languages, but we do show how to construct very efficient universal hash proof systems for a general class of group-theoretic language membership problems.<br /> <br />Given an efficient universal hash proof system for a language with certain natural cryptographic indistinguishability properties, we show how to construct an efficient public-key encryption schemes secure against adaptive chosen ciphertext attack in the standard model. Our construction only uses the universal hash proof system as a primitive: no other primitives are required, although even more efficient encryption schemes can be obtained by using hash functions with appropriate collision-resistance properties. We show how to construct efficient universal hash proof systems for languages related to the DCR and QR assumptions. From these we get corresponding public-key encryption schemes that are secure under these assumptions. We also show that the Cramer-Shoup encryption scheme (which up until now was the only practical encryption scheme that could be proved secure against adaptive chosen ciphertext attack under a reasonable assumption, namely, the Decision Diffie-Hellman assumption) is also a special case of our general theory.

A Memory Optimized Public-Key Crypto Algorithm Using Modified Modular Exponentiation (MME)

10.28945/3032 ◽  
2006 ◽  
Author(s):  
Ayodeji Oluwatope ◽  
Bamidele Ojo ◽  
G. Adesola Aderounmu ◽  
Matthew Adigun
Keyword(s):  
High Speed ◽  
Complexity Analysis ◽  
Data Communication ◽  
Data Encryption ◽  
Public Key ◽  
Modular Exponentiation ◽  
Public Key Encryption ◽  
Window Method ◽  
Encryption Schemes ◽  
Memory Applications

Since the advent of data communication over networks, it has become imperative to ensure security of information. Cryptography is a technique that is being employed. This paper takes a look at an important aspect of the public key encryption scheme, the modular exponentiation technique, with the view of optimizing it. Taking a look at some public key encryption schemes, it would be observed that the modular exponentiation process is primal to achieving high speed algorithms in data encryption. With special emphasis on the Montgomery exponentiation algorithm, a blend of this algorithm with the sliding window method of exponentiation is proposed. A detailed complexity analysis of the proposed and selected algorithms was carried out. Both algorithms were implemented and simulated using MATLAB 6.5. While the proposed algorithm did not prove to be faster than the classical Montgomery exponentiation algorithm, it was rather observed that it makes lesser number of calls to the Montgomery reduction sub-function. This means 10% lesser number of loops during execution and thus better optimized for lower memory applications.

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