Topic
40-bit encryption
About: 40-bit encryption is a research topic. Over the lifetime, 5434 publications have been published within this topic receiving 149016 citations.
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04 Oct 2010
TL;DR: In this paper, the authors proposed a new construction of CP-ABE, named Constant-size CP-ABCE, which significantly reduces the ciphertext to a constant size for an AND gate access policy with any given number of attributes.
Abstract: Existing CP-ABE schemes incur very large ciphertext size, which increases linearly with respect to the number of attributes in the access policy. Large ciphertext prevents CP-ABE from being adopted in the communication constrained environments. In this paper, we proposed a new construction of CP-ABE, named Constant-size CP-ABE (denoted as CCP-ABE) that significantly reduces the ciphertext to a constant size for an AND gate access policy with any given number of attributes. Each ciphertext in CCP-ABE requires only elements on a bilinear group.Based on CCP-ABE, we further proposed an Attribute Based Broadcast Encryption (ABBE) scheme. Compared to existing Broadcast Encryption (BE) schemes, ABBE is more flexible because a broadcasted message can be encrypted by an expressive access policy, either with or without explicit specifying the receivers. Moreover, ABBE significantly reduces the storage and communication overhead to the order of $O(\log N)$, where $N$ is the system size.
78 citations
11 Jul 2005
TL;DR: The first practical identity based encryption (IBE) scheme was proposed by Boneh and Franklin in [BF03] as discussed by the authors, but the authors pointed out that there is a flawed step in the security reduction exhibited by the authors.
Abstract: The first practical identity based encryption (IBE) scheme was proposed by Boneh and Franklin in [BF03] In this work we point out that there is a flawed step in the security reduction exhibited by the authors Fortunately, it is possible to fix it without changing the scheme or the underlying assumption
In the second place, we introduce a variant of the seminal IBE scheme which allows a more efficient security reduction This variant is simpler, and has more compact ciphertexts than Boneh-Franklin’s proposal, while keeping the computational cost
Finally, we observe that the flawed step pointed out here is present in several works, and that our techniques can be applied to obtain tighter reductions for previous relevant schemes
78 citations
TL;DR: An encryption algorithm which combines a DNA addition and a chaotic map to encrypt a gray scale image is proposed, which is non-invertible, which means that the receiver cannot decrypt the ciphered image even if he posses the secret key.
Abstract: In this paper, we propose to cryptanalyse an encryption algorithm which combines a DNA addition and a chaotic map to encrypt a gray scale image. Our contribution consists on, at first, demonstrating that the algorithm, as it is described, is non-invertible, which means that the receiver cannot decrypt the ciphered image even if he posses the secret key. Then, a chosen plaintext attack on the invertible encryption block is described, where, the attacker can illegally decrypt the ciphered image by a temporary access to the encryption machinery.
77 citations
28 Mar 2011
TL;DR: This work shows how to transform any additively homomorphic private-key encryption scheme that is compact, into a public-keyryption scheme, and shows that the length of a homomorphically generated encryption is independent of the number of ciphertexts from which it was created.
Abstract: We show how to transform any additively homomorphic private-key encryption scheme that is compact, into a public-key encryption scheme. By compact we mean that the length of a homomorphically generated encryption is independent of the number of ciphertexts from which it was created. We do not require anything else on the distribution of homomorphically generated encryptions (in particular, we do not require them to be distributed like real ciphertexts).
Our resulting public-key scheme is homomorphic in the following sense. If the private-key scheme is i+1-hop homomorphic with respect to some set of operations then the public-key scheme we construct is i-hop homomorphic with respect to the same set of operations.
77 citations
01 Jun 2015
TL;DR: It is proved security of the substring-searchable encryption scheme against malicious adversaries, where the query protocol leaks limited information about memory access patterns through the suffix tree of the encrypted string.
Abstract: In this paper, we consider a setting where a client wants to outsource storage of a large amount of private data and then perform substring search queries on the data – given a data string s and a search string p, find all occurrences of p as a substring of s. First, we formalize an encryption paradigm that we call queryable encryption, which generalizes searchable symmetric encryption (SSE) and structured encryption. Then, we construct a queryable encryption scheme for substring queries. Our construction uses suffix trees and achieves asymptotic efficiency comparable to that of unencrypted suffix trees. Encryption of a string of length n takes O(λn) time and produces a ciphertext of size O(λn), and querying for a substring of length m that occurs k times takes O(λm + k) time and three rounds of communication. Our security definition guarantees correctness of query results and privacy of data and queries against a malicious adversary. Following the line of work started by Curtmola et al. (ACM CCS 2006), in order to construct more efficient schemes we allow the query protocol to leak some limited information that is captured precisely in the definition. We prove security of our substring-searchable encryption scheme against malicious adversaries, where the query protocol leaks limited information about memory access patterns through the suffix tree of the encrypted string.
77 citations