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Probabilistic encryption - Wikipedia, the free encyclopedia Probabilistic encryption is the use of randomness in an encryption algorithm, so that when encrypting the same message several times it will, in general, yield different ciphertexts. The term "probabilistic encryption" is typically used in reference to public key encryption algorithms, however various symmetric key encryption algorithms achieve a similar property (e.g., block ciphers when used in a chaining mode such as CBC). The first provably-secure probabilistic public-key encryption scheme was proposed by Shafi Goldwasser and Silvio Micali, based on the hardness of the quadratic residuosity problem and had a message expansion factor equal to the public key size. en.wikipedia.org /wiki/Probabilistic_encryption   (399 words)

RSA Security - 7.1 What is probabilistic encryption? (via CobWeb/3.1 planetlab2.isi.jhu.edu)   (Site not responding. Last check: 2007-10-14) Probabilistic encryption, developed by Goldwasser and Micali [GM84], is a design approach for encryption where a message is encrypted into one of many possible ciphertexts (not just a single ciphertext as in deterministic encryption). In previous approaches to encryption, even though it was not always known whether one could obtain such partial information, it was not proved that one could not do so. A particular example of probabilistic encryption given by Goldwasser and Micali operates on ``bits'' rather than ``blocks'' and is based on the quadratic residuosity problem. www.rsasecurity.com.cob-web.org:8888 /rsalabs/node.asp?id=2337   (242 words)

IEEE P1363: Protocols from other families of public-key algorithms EPOC-2 is a public-key encryption system that uses a one-way trapdoor function, two random functions (hash functions) and a symmetric-key encryption (e.g., one-time padding and block-ciphers). The encryption scheme described in this contribution is obtained by combining three results: one [25] on the trapdoor function technique is by Okamoto and Uchiyama, and the others [13, 14] on conversion techniques using random functions are by Fujisaki and Okamoto. EPOC-3 is a public-key encryption system that uses the Okamoto-Uchiyama one-way trapdoor function and two random functions (hash functions) as well as any symmetric encryption scheme such as the one-time pad, or any classical block-cipher. grouper.ieee.org /groups/1363/StudyGroup/NewFam.html   (925 words)

Deterministic encryption - Wikipedia, the free encyclopedia A deterministic encryption scheme (as opposed to a probabilistic encryption scheme) is a cryptosystem which always produces the same ciphertext for a given plaintext and key, even over separate executions of the encryption algorithm. Examples of deterministic encryption algorithms include the RSA cryptosystem (without encryption padding), and many block ciphers when used in ECB mode or with a constant initialization vector. To counter this problem, cryptographers proposed the notion of "randomized" or probabilistic encryption. en.wikipedia.org /wiki/Deterministic_encryption   (323 words)

Cryptography In the classical case, encryption and decryption are handled by separate units in a hardware device acting as an interface between a user's computer and the network. Merkle assumes that encryption in a system such as DES defines a function EK, where K is a key, which produces a random output. Probabilistic algorithms are employed as adjuncts in cryptosystems for purposes such as finding primes. project.cyberpunk.ru /idb/cryptography.html   (17961 words)

Analysis of 802   (Site not responding. Last check: 2007-10-14) The encryption algorithm for WEP uses the RC4 stream cipher, used to generate the key stream, which is XORed against plaintext to produce ciphertext. The corresponding decryption algorithm is the same as the encryption algorithm; RC4 is used to generate the key stream, which is XORed against the ciphertext to reproduce the plaintext. Probabilistic encryption was invented by Shafi Goldwasser and Silvio Micali [4]. engr.smu.edu /~jojip/CSE8344PROJECT.html   (4261 words)

Encrypting off Processor Memory   (Site not responding. Last check: 2007-10-14) There are HDL models flying around of many encryption algorithms and almost a paper per University with a timing analysis for that encryption algorithm. Placing the encryption layer between the processor and the L1 cache should be avoided at all costs. The encryption layer between the L2 cache and main Memory causes a factor of 7.27 increase in the cycle count compared to running the benchmark without any encryption. www.w4g.org /ee565.html   (5496 words)

Initial secret key establishment including facilities for verification of identity - Patent 6061791 The PEKE cryptosystem is based on the Blum-Goldwasser probabilistic encryption scheme explained in an article by Manuel Blum and Shafi Goldwasser, An Efficient Probabilistic Public-key Encryption Scheme which Hides All Partial Information (in Advances in Cryptology: Proceedings of Crypto'84, Springer-Verlag, 1985, pp 289-299). In the preferred embodiment, the mentioned transformation is encryption and scaling with a Frogbit semi-proprietary algorithm using a secret key of the issuer. Then, DES encryption with the CBC mode of operation is applied to the pass query 206, the pass reply 209, and any portion of the other data 108 that deserves confidentiality protection, using another part of the internal secret key. www.freepatentsonline.com /6061791.html   (10899 words)

Probabilistic Encryption   (Site not responding. Last check: 2007-10-14) [References to ``the paper'' in this section are to ``Probabilistic Encryption,'' in Journal of Computer and System Sciences 28, pp. Probabilistic encryption is a system designed to avoid these problems. Indeed, the probability should be very close to 1 that if the same message is sent twice, the encryptions should be different. www.math.sunysb.edu /~scott/blair/Probabilistic_Encryption.html   (159 words)

Valery's blog - Wednesday, 18 January 2006   (Site not responding. Last check: 2007-10-14) In other words, for encryption scheme to be secure it is required to guarantee that is unfeasible to correlate ciphertexts of different messages in such way that information is leaked. Each encryption must use some randomness, or, say, a counter, and an encryption of a particular message must be different each time to satisfy indistinguishability requirements. Traditionally encryption was thought as analogue of codebook, a fixed mapping from plaintexts to ciphertexts. www.harper.no /valery/default,date,2006-01-18.aspx   (6575 words)

Efficient Protocols based on Probabilistic Encryption using Composite Degree Residue Classes   (Site not responding. Last check: 2007-10-14) We study various applications and variants of Paillier's probabilistic encryption scheme. First, we propose a threshold variant of the scheme, and also zero-knowledge protocols for proving that a given ciphertext encodes a given plaintext, and for verifying multiplication of encrypted values. Finally, we propose a variant of the encryption scheme, that allows reducing the expansion factor of Paillier's scheme from 2 to almost 1. www.brics.dk /RS/00/5   (181 words)

Public key cryptosystem method and apparatus - Patent 6081597 The public key encryption system of the present invention has short and easily created encryption keys and wherein the encoding and decoding processes are performed extremely rapidly, and has low memory requirements. The cryptosystem of the present invention allows encryption keys to be chosen essentially at random from a large set of binary vectors, for which key lengths are comparable to the key lengths of the most widely used prior art cryptosystems. It is also among the objects hereof to provide a public key encryption system which has relatively low memory requirements and which depends on a variety of parameters that permit substantial flexibility in balancing security level, key length, encoding and decoding speed, memory requirements, and bandwidth. www.freepatentsonline.com /6081597.html   (6676 words)

Public key algorithms   (Site not responding. Last check: 2007-10-14) RSA is a cryptosystem for both encryption and authentication developed in 1977 by Ron ELGAMAL is an encryption algorithm based on the discrete logarithm problem. Probabilistic encryption is a different approach for encryption discovered by Goldwasser and Micali. www.wowarea.com /english/help/pubalg.htm   (203 words)

[No title]   (Site not responding. Last check: 2007-10-14) These encryption systems are referred to as homomorphic and have applications in electronic voting, network coding and secure processing. An important example of an homomorphic encryption is Paillier encryption, a probabilistic encryption system that preserves addition of plain-text messages. In this talk we discuss Paillier encryption from the perspective of simple groups theory using the notions of split short exact sequences and the Chinese Remainder Theorem. isl.stanford.edu /abstracts/jan26_2006TK.html   (107 words)

Dense Probabilistic Encryption This paper describes a method of dense probabilistic encryption. Previous probabilistic encryption methods require large numbers of random bits and product large amounts of ciphertext for the encryption of each bit of plaintext. This paper develops a method of probabilistic encryption in which the ratio of ciphertext text size to plaintext size and theproportion of random bits to plaintext can both be made arbitrarily close to one. research.microsoft.com /research/pubs/view.aspx?pubid=460   (106 words)

Lecture Schedule Non-trivial private-key encryption implies private-key encryption in which the message is much longer than the key. References: The encryption scheme based on the hardness of deciding quadratic residuosity is based on the first secure public-key encryption scheme due to Goldwasser and Micali [GM84]. References: For more information about chosen-ciphertext attacks, see: the paper describing the only known efficient encryption scheme which is provably-secure against chosen-ciphertext attacks or another paper describing a scheme in the random oracle model (a variant of which is used extensively in practice). www.cs.umd.edu /~jkatz/gradcrypto/syllabus.html   (1697 words)

Introduction The schemes of the first two categories satisfy all of the properties mentioned above, but the blind signature based schemes are much more efficient because of their low complexity of computation and simplicity of protocols. The schemes based on probabilistic encryption and homomorphic functions are designed to be receipt-free. In such schemes, it is difficult for a voter to prove to someone else that how he voted, therefore buying and selling votes could be avoided. www.cs.cmu.edu /~qihe/paper/e_voting/node1.html   (843 words)

Probabilistic Encryption Key Exchange We propose a novel secret key exchange algorithm in which security is partially based on the Blum-Goldwasser probabilistic encryption cryptosystem [4] and the mathematical properties of the BBS pseudo-random number generator [5-7]. The probabilistic encryption key exchange (PEKE) cryptosystem is an adaptation of the Blum-Goldwasser cryptosystem for the task of secret key exchange. The Rabin probabilistic primality test [9] can be run in parallel for these three numbers and aborted as soon as any of them is known to be composite. www.connotech.com /PEKEELEC.HTM   (1069 words)

Semantic security - Wikipedia, the free encyclopedia For a cryptosystem to be semantically secure, it must be infeasible for a computationally-bounded adversary to derive significant information about a message (plaintext) when given only its ciphertext and the corresponding public encryption key. A probabilistic polynomial time-bounded adversary is given a public key, which it may use to generate any number of ciphertexts (within polynomial bounds). Goldwasser and S. Micali, Probabilistic encryption and how to play mental poker keeping secret all partial information, Annual ACM Symposium on Theory of Computing, 1982. en.wikipedia.org /wiki/Semantic_security   (525 words)

Advanced Cryptography   (Site not responding. Last check: 2007-10-14) A Simpler Construction of CCA2-Secure Public Key Encryption under Generic Assumptions." in Eurocrypt 03. Authenticated Encryption: Relations among notions and analysis of the generic composition paradigm. Chosen ciphertext security from identity-based encryption," Eurocrypt 2004. www-users.itlabs.umn.edu /classes/Spring-2005/csci8980-3   (451 words)

[No title]   (Site not responding. Last check: 2007-10-14) "On the security of ElGamal-based encryption" Abstract The ElGamal encryption scheme has been proposed several years ago and is one of the few probabilistic encryption schemes. In addition, we show that the opposite direction holds, i.e., the semantic security of the ElGamal encryption is actually equivalent to the decision Diffie-Hellman problem. Non-malleability is equivalent to the decision Diffie-Hellman assumption, the existence of a random oracle (in practice a secure hash function) or a trusted beacon (as needed for the Fiat-Shamir argument), and one assumption about the unforgeability of Schnorr signatures. www.ccs.neu.edu /home/yiannis/papers/egAbs.txt   (166 words)

PEKE, Probabilistic Encryption Key Exchange, 10 Years Later, Including the PEKEv1.25 Specifications (ResearchIndex) Abstract: This document revisits the PEKE (Probabilistic Encryption Key Exchange) cryptosystem and proposes the enhanced PEKEv1.25 that performs a hash computation on the original PEKE output in order to improve the security assurance and to broaden the field of use. For a key establishment application where only the server side publishes a long-term public key and can adequately protect the private key counterpart from implementation attacks, we claim that PEKE is unsurpassed in security and efficiency,... 2 A Modification of RSA Public-Key Encryption (context) - Hugh - 1980 citeseer.ist.psu.edu /moreau05peke.html   (591 words)

US patent appl. no. 09,296,378, filed on 1999/04/22 In the preferred embodiment, the said transformation is encryption and sealing with a Frogbit semi-proprietary algorithm using a secret key of the issuer. With PK-Encr, this is the public key encryption of the said internal secret key, using the public key 204, the ciphertext being included in the second message 104. Then, DES encryption with the CBC mode of operation is applied to the pass query 206, the pass reply 209, and any portion of the other data 108 that deserves confidentiality protection, using another part of the said internal secret key. www.connotech.com /BREVUS.HTM   (9818 words)

[No title]   (Site not responding. Last check: 2007-10-14) Namely, the encryption processes are done much faster and the smaller key size is ideal for limited bandwidth applications (e.g. Regarding the issue of encryption capability mentioned in the request for comments: > Any algorithms proposed for digital signature must be able > to be implemented such that they do not support encryption unless keys > used for encryption are distinct from those used for signature and are > recoverable. While it is true that some digital signature primitives alone may provide encryption capability (including DSA variants and their elliptic curve analogues as well as RSA), any such primitive can be combined with a hash function to eliminate unintended use as an encryption function. csrc.nist.gov /encryption/kms/keyxcmts.txt   (8055 words)

859I Class Schedule Bellare and Namprempre, " Authenticated Encryption: Relations among notions and analysis of the generic composition paradigm. Goldwasser and Micali, "Probabilistic Encryption." Journal of Computer and System Sciences vol 28, 270-299 (1984). Bellare and Rogaway, " Optimal asymmetric Encryption" Eurocrypt 94. www.cs.cmu.edu /~hopper/crypto_course/schedule.html   (478 words)

sci.crypt: Re: homomorphic encryption encryption scheme exists then you can break the encryption scheme in ECB encryption is hopelessly weak -- its insecurity is precisely one,... >>>encryption scheme in the strenth of the cipher text. www.derkeiler.com /Newsgroups/sci.crypt/2003-06/0072.html   (417 words)

Slashdot | NetBSD's Crypto-Graphic Disk But probabilistic encryption implies the encrypted version must be slightly larger than the clear text. Having journaling both in the encryption and in the file system seems to be overkill (and clearly hurts performance), but integrating the two without compromising security is nontrivial. To the best of my knowledge GBDE is currently the only disk encryption making use of probabilistic encryption, and none of the disk encryptions in existence make a serious effort at guaranteeing integrity (also known as security against an active adversary). rss.slashdot.org /Slashdot/slashdotBsd?m=27   (4042 words)

sci.crypt: Re: chaining algorithms together definition of what a (symmetric) encryption scheme is, and what it means * E is a probabilistic `encryption algorithm': given a `key' K in keys A /(t, q, m)-adversary/ is a probabilistic oracle algorithm www.derkeiler.com /Newsgroups/sci.crypt/2003-07/1076.html   (560 words)

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