Adaptive Chosen Plaintext Attacks Research Articles

CBC Mode of MPF Based Shannon Cipher Defined Over a Non-Commuting Platform Group

Commonly modern symmetric encryption schemes (e.g. AES) use rather simple actions repeated many times by defining several rounds to calculate the ciphertext. An idea we previously offered was to trade these multiple repeats for one non-linear operation. Recently we proposed a perfectly secure symmetric encryption scheme based on the matrix power function (MPF). However, the platform group we used was commuting. In this paper, we use a non-commuting group whose cardinality is a power of 2 as a platform for MPF. Due to the convenient cardinality value, our scheme is more suitable for practical implementation. Moreover, due to the non-commuting nature of the platform group, some “natural” constraints on the power matrices arise. We think that this fact complicates the cryptanalysis of our proposal. We demonstrate that the newly defined symmetric cipher possesses are perfectly secure as they were previously done for the commuting platform group. Furthermore, we show that the same secret key can be used multiple times to encrypt several plaintexts without loss of security. Relying on the proven properties we construct the cipher block chaining mode of the initial cipher and show that it can withstand an adaptive chosen plaintext attack.

AMOUN: Asymmetric lightweight cryptographic scheme for wireless group communication

Multi-recipient cryptographic schemes provide secure communication, between one sender and multiple recipients, in a multi-party group. Providing secure multi-party communication is very challenging, especially in dynamic networks. Existing multi-recipient cryptographic schemes pose a variety of limitations. These include high computational overhead for both encryption and decryption, additional communication overhead and high setup cost due to change in membership, and collusion among recipients. In order to overcome these limitations, this paper introduces an efficient asymmetric multi-recipient cryptographic scheme, AMOUN. In the proposed scheme, to better utilize network resources, the sender transmits a ciphertext containing different messages to multiple recipients, where each recipient is only allowed to retrieve its own designated message. Security analysis demonstrates that the proposed scheme is indistinguishable under adaptive chosen plaintext attack. Quantitative analysis reveals that lightweight AMOUN shows lower average computational cost than both RSA and Multi-RSA, for both encryption and decryption, even when the key sizes are four times larger. For a given prime size, in case of encryption, AMOUN shows 98% and 99% lower average computational cost than RSA and Multi-RSA, respectively. For decryption, AMOUN shows a performance improvement of 99% compared to RSA and Multi-RSA.

Efficient Revocable Multi-Authority Attribute-Based Encryption for Cloud Storage

As is known, attribute-based encryption (ABE) is usually adopted for cloud storage, both for its achievement of fine-grained access control over data, and for its guarantee of data confidentiality. Nevertheless, single-authority attribute-based encryption (SA-ABE) has its obvious drawback in that only one attribute authority can assign the users' attributes, enabling the data to be shared only within the management domain of the attribute authority, while rendering multiple attribute authorities unable to share the data. On the other hand, multi-authority attribute-based encryption (MA-ABE) has its advantages over SA-ABE. It can not only satisfy the need for the fine-grained access control and confidentiality of data, but also make the data shared among different multiple attribute authorities. However, existing MA-ABE schemes are unsuitable for the devices with resources-constraint, because these schemes are all based on expensive bilinear pairing. Moreover, the major challenge of MA-ABE scheme is attribute revocation. So far, many solutions in this respect are not efficient enough. In this paper, on the basis of the elliptic curves cryptography, we propose an efficient revocable multi-authority attribute-based encryption (RMA-ABE) scheme for cloud storage. The security analysis indicates that the proposed scheme satisfies indistinguishable under adaptive chosen plaintext attack assuming hardness of the decisional Diffie-Hellman problem. Compared with the other schemes, the proposed scheme gets its advantages in that it is more economical in computation and storage.

Towards Unsecurity of Two Homomorphic Encryptions Based on Residue System

The security of two recently proposed symmetric homomorphic encryption schemes based on residue system is analyzed.
 Both schemes have a high computational efficiency since using residue system naturally allows parallelizing computations. So they could be good candidates to protect the data in clouds. But to the best of our knowledge there is a lack of security analysis for these encryption schemes.
 It should be noted that the first cryptosystem under our consideration was already considered in literature.
 The sketch of adaptive chosen-plaintext attack was proposed and estimation of its success was given.
 In this paper the attack is analyzed and it is shown that in some cases it may work incorrectly. Also more general algorithm of known-plaintext attack is presented. Theoretical estimations of probability to recover the key using it and practical estimations of this probability obtained during the experiments are provided.
 The security of the second cryptosystem has not been analyzed yet and we fill this gap for known-plaintext attack. The dependency between the number of «plaintext, ciphertext» pairs required to recover the key and parameters of the cryptosystem is analyzed. Also some recommendations for increasing the security level are provided.
 The final conclusion of our analysis is that both cryptosystems are vulnerable to known-plaintext attack. And it may be dangerous to encrypt private data using them.
 Finally it should be noted that the key element of the proposed attacks is the algorithm of computing the greatest common divisor. So their computational complexity depends polynomially on the size of input data.

Efficient biometric identity-based encryption

As a special case of public key encryption, identity-based encryption (IBE) takes any public known information as public key for encryption and then decrypts a ciphertext by a well-generated private key from private key generator (PKG). Unlike the traditional IBE using a text-based identity (e-mail, etc.) as public key, in this paper, we aim to design a secure, time-saving and space-saving biometric identity-based encryption (BIBE) regarding the biometric-based identity (face, etc.) as public key. To overcome the challenge introduced by the fuzziness of biometric identities, First, we propose a provable-secure inner-product encryption (IPE) with short ciphertext and show the IPE is indistinguishable against selective identity, adaptive chosen-plaintext attack (IND-sID-CPA). Then, we construct a distance-based encryption (DBE) leveraging the proposed IPE and prove that the DBE captures the same security with the underlying IPE. Furthermore, we optimize the proposed DBE so that it also has short private key. We theoretically analyze the overhead of IPE, DBE, and optimized DBE (ODBE) in terms of time, space, and communication complexities. We also conduct experiments to measure the time and space costs of the proposed ODBE, and experimental results validate its effectiveness and efficiency.

Provably secure identity-based encryption resilient to post-challenge continuous auxiliary input leakage

The situation for post-challenge continuous auxiliary input leakage has not been considered in the cryptography schemes for previous literature. We present a semantic-security model with post-challenge continuous auxiliary inputs for identity-based encryption. In this model, the adversary is permitted to obtain some information of the private keys constantly and to query more information after seeing the challenge ciphertext through the side-channel attacks. Furthermore, we present an identity-based encryption scheme resilient to leakage under composite order groups. Our scheme is secure against post-challenge continuous auxiliary input, adaptive chosen-identity, and adaptive chosen plaintext attacks under three static assumptions in the standard model. Compared with existing identity-based encryption schemes under security properties and performance, our scheme is practical. Copyright © 2015 John Wiley & Sons, Ltd.

Breaking an ID-based encryption based on discrete logarithm and factorization problems

Identity-based (ID-based) cryptography is very useful as it can simplify the certificate management in public key cryptosystem. Since 2001, researchers have introduced various practical and efficient ID-based encryption schemes. Most of them are based on pairings, under the Diffie–Hellman assumptions. Recently, Meshram [1] proposed a new ID-based encryption scheme which was not based on pairing-based cryptography. He proved that his scheme was secure against adaptive chosen plaintext attack, as its security was based on the difficulty of discrete logarithm and integer factorization problems. However, in this paper, we show that this new ID-based encryption scheme is insecure by presenting a method to recover the secret master key.

Four Stage Encryption Generalizations: Partitioned Output Cryptosystem

The Four Stage Encryption System introduced by Acharyulu and Appaji provides secrecy even when the attacker has some samples of plain texts and their corresponding cipher texts obtained with the same key, because the cipher text generated each time, for the same plain text with the same key, is different. In other words, the system is secure against adaptive chosen-plain text attack. Another interesting feature is that even the size of the cipher text, for given plain text under a given key, is unpredictable. In this paper the four stage encryption system is generalized as Generated Partitioned Output Crypto System and some variations that can be taken up are suggested. A pure mathematical system called Partitioned Output Crypto System is introduced as a further step of generalization in order to study the properties of the system. A correlation with the existing systems is taken up as a part of the study of the properties. It‟s observed that the system shares the properties of multifunction. General Terms Cryptography, Cryptanalysis, Security.

Anonymous encryption with partial‐order subset delegation and its application in privacy email systems

In privacy-carrying email systems, the authors should guarantee that the email content is confidential and sometimes the sender/receiver identities are hidden. Also, they require that the key generation is flexible and manageable. In this study, first, they propose an anonymous encryption scheme that supports a partial-order subset delegatable ability. The proposed scheme achieves the security properties of confidentiality against adaptive chosen-plaintext attacks, anonymity against adaptive chosen-subset attacks and computational delegation indistinguishability. Secondly, they provide a deployment application of their anonymous encryption in an interdisciplinary group email management system with flexible and fine-grained key delegation. The deployment can achieve the privacy of message confidentiality, receiver anonymity and delegation obliviousness, which has fine-grained security in secure email systems. Finally, they provide an extension for the chosen-ciphertext secure scheme, and discuss the efficiency for decryption and the security level.

Certificate-based proxy decryption systems with revocability in the standard model

We present the concept of a certificate-based proxy decryption (CBPd) system with revocability, which has the following properties: (1) key-escrow freeness; (2) implicit certification; (3) revocability without public key change; and (4) fine-grained delegation. A concrete CBPd scheme is also proposed. The scheme is semantically secure against adaptive chosen plaintext attack (IND-CBPd-Rev-CPA) under the decisional bilinear Diffie-Hellman assumption in the standard model. We also give an enhanced scheme that is secure against adaptive chosen ciphertext attacks (IND-CBPd-Rev-CCA) in the standard model.

Efficient Revocable ID-Based Encryption with a Public Channel

Over the last few years, identity (ID)-based encryption (IBE) without requiring certificate management offers a practical alternative to public key encryption. However, how to revoke misbehaving/compromised identities in ID-based public key setting becomes a new and critical issue. In the past, there was little work on studying this revocation problem. In 2008, Boldyreva et al. proposed a revocable IBE (RIBE) and its associated revocation solution that used a binary tree structure to reduce the authority's periodic workload in Boneh and Franklin's IBE. However, Boldyreva et al.'s RIBE raised enormous computation costs for encryption and decryption procedures. Both IBEs require a secure channel between each user and the authority to transmit user's periodic private keys, thus the authority and each user need to encrypt and decrypt the private keys for each period. In this article, we present an efficient RIBE with a public channel, which provides a practical alternative to the previously proposed revocation solutions, while it remains efficient for encryption and decryption. Under the bilinear Diffie–Hellman assumption, we demonstrate that our RIBE with a public channel is semantically secure against adaptive chosen plaintext attacks and adaptive chosen ciphertext attacks.

A Practical Forward-Secure Public-Key Encryption Scheme

In open network, cryptographic operations are often performed on insecure, unprotected, and easily-stolen devices, therefore the threat of secret key exposure becomes more and more acute. The paradigm of forward security provides a promising approach to deal with the secret key exposure. This new paradigm guarantees that the compromise of current secret keys does not compromise past secret keys and past communications. Therefore, forward-security can minimize the resulting damage caused by the secret key exposure. In this paper, we present a practical forward-secure public-key encryption (FS-PKE) scheme and prove it to be forward-secure against selective-time period and adaptive chosen plaintext attacks in the standard model. The main performance parameters of our proposed scheme are independent on the total number of time periods in the scheme. When compared with the existing FS-PKE scheme, our proposed scheme is much more efficient and practical. We also discuss how our scheme achieves chosen ciphertext security in the standard model and in the random oracle model respectively.

Anonymous Multireceiver Identity-Based Encryption

Recently, many multireceiver identity-based encryption schemes have been proposed in the literature. However, none can protect the privacy of message receivers among these schemes. In this paper, we present an anonymous multireceiver identity-based encryption scheme where we adopt Lagrange interpolating polynomial mechanisms to cope with the above problem. Our scheme makes it impossible for an attacker or any other message receiver to derive the identity of a message receiver such that the privacy of every receiver can be guaranteed. Furthermore, the proposed scheme is quite receiver efficient since each of the receivers merely needs to perform twice of pairing computation to decrypt the received ciphertext. We prove that our scheme is secure against adaptive chosen plaintext attacks and adaptive chosen ciphertext attacks. Finally, we also formally show that every receiver in the proposed scheme is anonymous to any other receiver.

On the Security of the Secure Arithmetic Code

In 2007, Kim et al. proposed a secure compression code called the secure arithmetic code (SAC). The code was claimed to be secure against chosen plaintext attacks. However, we find that the SAC is not as secure as the authors have claimed. In this paper, we show the code is prone to two attacks. The first attack completely breaks the code using an adaptive chosen plaintext attack with a polynomial number of queries. The second attack is a ciphertext-only attack, which removes a part of the output permutation.

Characterization of Security Notions for Probabilistic Private-Key Encryption

The development of precise definitions of security for encryption, as well as a detailed n understanding of their relationships, has been a major area of research in modern cryptography. Here, we focus on the case of private-key encryption. Extending security notions from the public-key setting, we define security in the sense of both indistinguishability and non-malleability against chosen-plaintext and chosen-ciphertext attacks, considering both non-adaptive (i.e., lunchtime) and adaptive oracle access (adaptive here refers to an adversary's ability to interact with a given oracle even after viewing the challenge ciphertext). We then characterize the 18 resulting security notions in two ways. First, we construct a complete hierarchy of security notions; that is, for every pair of definitions we show whether one definition is stronger than the other, whether the definitions are equivalent, or whether they are incomparable. Second, we partition these notions of security into two classes (computational or information-theoretic) depending on whether one-way functions are necessary in order for encryption schemes satisfying the definition to exist. Perhaps our most surprising result is that security against adaptive chosen-plaintext attack is (polynomially) equivalent to security against non-adaptive chosen-plaintext attack. On the other hand, the ability of an adversary to mount a (non-adaptive) chosen-plaintext attack is the key feature distinguishing computational and information theoretic notions of security. These results hold for all security notions considered here.

Characterization of Security Notions for Probabilistic Private-Key Encryption

The development of precise definitions of security for encryption, as well as a detailed understanding of their relationships, has been a major area of research in modern cryptography. Here, we focus on the case of private-key encryption. Extending security notions from the public-key setting, we define security in the sense of both indistinguishability and non-malleability against chosen-plaintext and chosen-ciphertext attacks, considering both non-adaptive (i.e., ``lunchtime'') and adaptive oracle access (adaptive here refers to an adversary's ability to interact with a given oracle even after viewing the challenge ciphertext). We then characterize the 18 resulting security notions in two ways. First, we construct a complete hierarchy of security notions; that is, for every pair of definitions we show whether one definition is stronger than the other, whether the definitions are equivalent, or whether they are incomparable. Second, we partition these notions of security into two classes (computational or information-theoretic) depending on whether one-way functions are necessary in order for encryption schemes satisfying the definition to exist. Perhaps our most surprising result is that security against adaptive chosen-plaintext attack is (polynomially) equivalent to security against non-adaptive chosen-plaintext attack. On the other hand, the ability of an adversary to mount a (non-adaptive) chosen-plaintext attack is the key feature distinguishing computational and information-theoretic notions of security. These results hold for all security notions considered here.