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Plaintext

About: Plaintext is a research topic. Over the lifetime, 7269 publications have been published within this topic receiving 108928 citations. The topic is also known as: cleartext.


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Proceedings ArticleDOI
14 May 2000
TL;DR: This work describes the cryptographic schemes for the problem of searching on encrypted data and provides proofs of security for the resulting crypto systems, and presents simple, fast, and practical algorithms that are practical to use today.
Abstract: It is desirable to store data on data storage servers such as mail servers and file servers in encrypted form to reduce security and privacy risks. But this usually implies that one has to sacrifice functionality for security. For example, if a client wishes to retrieve only documents containing certain words, it was not previously known how to let the data storage server perform the search and answer the query, without loss of data confidentiality. We describe our cryptographic schemes for the problem of searching on encrypted data and provide proofs of security for the resulting crypto systems. Our techniques have a number of crucial advantages. They are provably secure: they provide provable secrecy for encryption, in the sense that the untrusted server cannot learn anything about the plaintext when only given the ciphertext; they provide query isolation for searches, meaning that the untrusted server cannot learn anything more about the plaintext than the search result; they provide controlled searching, so that the untrusted server cannot search for an arbitrary word without the user's authorization; they also support hidden queries, so that the user may ask the untrusted server to search for a secret word without revealing the word to the server. The algorithms presented are simple, fast (for a document of length n, the encryption and search algorithms only need O(n) stream cipher and block cipher operations), and introduce almost no space and communication overhead, and hence are practical to use today.

3,300 citations

Journal ArticleDOI
TL;DR: Performance measurements of the experimental file system demonstrate the usefulness of proxy re-encryption as a method of adding access control to a secure file system and present new re-Encryption schemes that realize a stronger notion of security.
Abstract: In 1998, Blaze, Bleumer, and Strauss (BBS) proposed an application called atomic proxy re-encryption, in which a semitrusted proxy converts a ciphertext for Alice into a ciphertext for Bob without seeing the underlying plaintext. We predict that fast and secure re-encryption will become increasingly popular as a method for managing encrypted file systems. Although efficiently computable, the wide-spread adoption of BBS re-encryption has been hindered by considerable security risks. Following recent work of Dodis and Ivan, we present new re-encryption schemes that realize a stronger notion of security and demonstrate the usefulness of proxy re-encryption as a method of adding access control to a secure file system. Performance measurements of our experimental file system demonstrate that proxy re-encryption can work effectively in practice.

1,598 citations

Proceedings ArticleDOI
19 Oct 1997
TL;DR: This work studies notions and schemes for symmetric (ie. private key) encryption in a concrete security framework and gives four different notions of security against chosen plaintext attack, providing both upper and lower bounds, and obtaining tight relations.
Abstract: We study notions and schemes for symmetric (ie. private key) encryption in a concrete security framework. We give four different notions of security against chosen plaintext attack and analyze the concrete complexity of reductions among them, providing both upper and lower bounds, and obtaining tight relations. In this way we classify notions (even though polynomially reducible to each other) as stronger or weaker in terms of concrete security. Next we provide concrete security analyses of methods to encrypt using a block cipher, including the most popular encryption method, CBC. We establish tight bounds (meaning matching upper bounds and attacks) on the success of adversaries as a function of their resources.

1,089 citations

Patent
06 Dec 2001
TL;DR: In this paper, a distributed storage system and a compiler is used to reconstruct plaintext based on security clearance for the community of the inquiring party. But full or partial plaintext reconstruction is permitted only in the presence of assigned security clearance.
Abstract: Data is secured in a computer network to transparently establish and manage a separation of user-based communities of interest based upon crypto-graphically separated, need to know, security levels. Data from a source document, data object or data stream is filtered to form subsets of extracted data and remainder data based upon security levels for the communities. Extracts are stored in assigned memories. Full or partial plaintext reconstruction is permitted only in the presence of assigned security clearance for the community of the inquiring party. Encryption, corresponding to security levels, establishes separation of secured data. The information processing system uses a data filter to extract security sensitive words, data objects, etc., a distributed storage system and a compiler is used to reconstruct plaintext based on security clearance. Multiple level encryption in one document is also available.

1,084 citations

Journal Article
TL;DR: In this article, the relative strengths of popular notions of security for public key encryption schemes are compared under chosen plaintext attack and two kinds of chosen ciphertext attack, and the goals of privacy and non-malleability are considered.
Abstract: We compare the relative strengths of popular notions of security for public key encryption schemes. We consider the goals of privacy and non-malleability, each under chosen plaintext attack and two kinds of chosen ciphertext attack. For each of the resulting pairs of definitions we prove either an implication (every scheme meeting one notion must meet the other) or a separation (there is a scheme meeting one notion but not the other, assuming the first notion can be met at all). We similarly treat plaintext awareness, a notion of security in the random oracle model. An additional contribution of this paper is a new definition of non-malleability which we believe is simpler than the previous one.

1,057 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023235
2022522
2021371
2020614
2019813
2018705