advantage
American Heritage Dictionary:
Top
ad·van·tage
(ăd-văn'tĭj) 
n.
To afford profit or gain to; benefit.
idioms:
n.
- A beneficial factor or combination of factors.
- Benefit or profit; gain: It is to your advantage to invest wisely.
- A relatively favorable position; superiority of means: A better education gave us the advantage.
- Sports.
- The first point scored in tennis after deuce.
- The resulting score.
To afford profit or gain to; benefit.
idioms:
take advantage of
- To put to good use; avail oneself of: take advantage of all educational opportunities.
- To profit selfishly by; exploit: took advantage of the customer.
- To good effect; favorably: The roses were displayed to advantage in a blue vase.
[Middle English avantage, from Old French, from avant, before, from Latin abante, from before. See advance.]
Roget's Thesaurus:
Top
advantage
noun
- A factor conducive to superiority and success: handicap, head start, odds, start, vantage. See help/harm/harmless.
- Something beneficial: avail, benefit, blessing, boon, favor, gain, profit. See help/harm/harmless.
- Something that contributes to or increases one's well-being: benefit, good, interest (often used in plural), profit. See help/harm/harmless.
- The quality of being suitable or adaptable to an end: account, avail, benefit, profit, use, usefulness, utility. See used/unused.
- A dominating position, as in a conflict: better, bulge, draw, drop, edge, superiority, upper hand, vantage. Informal inside track, jump. See over/under.
verb
- To be an advantage to: avail, benefit, profit, serve. Archaic boot. Idioms: stand someone in good stead. See help/harm/harmless.
Antonyms by Answers.com:
Top
advantage
n
Definition: benefit, favored position or circumstance
Antonyms: disadvantage, drawback, handicap, hindrance, loss, obstacle, restriction
Word Tutor:
Top
advantage
IN BRIEF: A more favorable position; better chance.
To every disadvantage there is a corresponding advantage.
— W. Clement Stone; American entrepreneur
LearnThatWord.com is a free vocabulary and spelling program where you only pay for results!
Sign Language Videos:
Top
advantage
sign description: The middle finger taps the palm of the hand and then pulls away quickly.
Quotes About:
Top
Advantage
Quotes:
"In life, as in chess, forethought wins."
- Charles Buxton
"If we do what is necessary, all the odds are in our favor."
- Henry Kissinger
"If eighty percent of your sales come from twenty percent of all of your items, just carry those twenty percent."
- Stew Leonard
"He who is in love with himself has at least this advantage -- he won't encounter many rivals."
- Georg C. Lichtenberg
"The two big advantages I had at birth were to have been born wise and to have been born in poverty."
- Sophia Loren
"It is a great advantage for a system of philosophy to be substantially true."
- George Santayana
See more famous quotes about Advantage
Random House Word Menu:
Top
categories related to 'advantage'
See crossword solutions for the clue Wikipedia on Answers.com:
Top
Advantage (cryptography)
 |
This article may require cleanup to meet Wikipedia's quality standards. (Consider using more specific cleanup instructions.) Please help improve this article if you can. The talk page may contain suggestions. (March 2008) |
In cryptography, an adversary's advantage is a measure of how successfully it can attack a cryptographic algorithm, by distinguishing it from an idealized version of that type of algorithm. Note that in this context, the "adversary" is itself an algorithm and not a person. A cryptographic algorithm is considered secure if no adversary has a non-negligible advantage, subject to specified bounds on the adversary's computational resources (see concrete security). "Negligible" usually means "within O(2-p)" where p is a security parameter associated with the algorithm. For example, p might be the number of bits in a block cipher's key.
|
Contents
|
Description of concept
Let F be an oracle for the function being studied, and let G be an oracle for an idealized function of that type. The adversary A is a probabilistic algorithm given F or G as input and which outputs 1 or 0. A's job is to distinguish F from G based on making queries to the oracle that it's given. We say: ![Adv(A) = |\Pr[A(F)=1] - \Pr[A(G)=1]|](http://wpcontent.answcdn.com/wikipedia/en/math/2/3/2/2327a640881019c9a5b701b3d8b6b0d0.png)
Examples
Let F be a random instance of the DES block cipher. This cipher has 64-bit blocks and a 56-bit key. The key therefore selects one of a family of 256 permutations on the 264 possible 64-bit blocks. A "random DES instance" means our oracle F computes DES using some key K (which is unknown to the adversary) where K is selected from the 256 possible keys with equal probability.
We want to compare the DES instance with an idealized 64-bit block cipher, meaning a permutation selected at random from the (264)! possible permutations on 64-bit blocks. Call this randomly selected permutation G. Note from Stirling's approximation that (264)! is around 
, so even specifying which permutation is selected requires writing down a number too large to represent exactly in any real computer. Viewed another way, G is an instance of a "cipher" whose "key length" is about 1021 bits, which again is too large to fit in a computer. (We can, however, implement G with storage space proportional to the number of queries, using a random oracle).
Note that because the oracles we're given encrypt plaintext of our choosing, we're modelling a chosen-plaintext attack or CPA, and the advantage we're calculating can be called the CPA-advantage of a given adversary. If we also had decryption oracles available, we'd be doing a chosen-ciphertext attack or CCA and finding the CCA-advantage of the adversary.
We'll look at several different adversaries and see how they perform.
Example 1: Guess at random
We'll call this adversary A0. It simply flips a coin and returns 1 or 0 with equal probability and without making any oracle calls. Thus, Pr[A0(F)=1] and Pr[A0(G)=1] are both 0.5. The difference between these probabilities is zero, so Adv(A0) is zero. The same thing applies if we always return 0, or always return 1: the probability is the same for both F and G, so the advantage is zero. This adversary can't tell F and G apart. If we're cipher designers, our desire (maybe not achievable) is to make it so that it's computationally infeasible for any adversary to do significantly better than this. We will have succeeded if we can make a cipher for which there's no distinguisher faster than brute force search.
Example 2: Brute force search
This adversary (call it A1) will attempt to cryptanalyze its input by brute force. It has its own DES implementation. It gives a single query to its oracle, asking for the 64-bit string of all zeroes to be encrypted. Call the resulting ciphertext E0. It then runs an exhaustive key search. The algorithm looks like this:
E0 = oracle_query(0)
for k in 0,1,...,256-1:
if DESk(0) == E0:
return 1
return 0
This searches the entire 56-bit DES keyspace and returns "1" if it probably finds a matching key. In practice, several plaintexts are required to confirm the key, as two different keys can result in one or more matching plaintext-ciphertext pairs. If no key is found, it returns 0.
If the input oracle is DES, this exhaustive search is certain to find the key, so Pr[A1(F)=1] = 1. If the input oracle is a random permutation, there are 264 possible values of E0, and at most 256 of them will get examined in the DES keysearch. So the probability of A1 returning 1 is at most 2-8. That is:
Pr[A1(G)=1] <= 2-8, so
Adv(A1) = |Pr[A1(F)=1] - Pr[A1(G)=1]| >= 1 - 2-8
so the advantage is at least about 0.996. This is a near-certain distinguisher, but it's not a security failure because it's no faster than brute force search, after all, it is the brute force search.
See also
References
Phillip Rogaway and Mihir Bellare, Introduction to Modern Cryptography
Oded Goldreich, Foundations of Cryptography (Fragments of a Book)
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
Translations:
Top
Advantage
Dansk (Danish)
n. - fordel, gunstig, omstændighed
v. tr. - gavne, være til fordel for, være til nytte for
idioms:
- take advantage of udnytte, drage fordel af, misbruge
- to good advantage fra den mest fordelagtige side
- to your advantage til din fordel, i din favør
- turn to one's advantage drage fordel af, udnytte, vende til ens egen fordel
Nederlands (Dutch)
voordeel, overwicht, advantage (tennis), bevoordelen, bevorderen het beste tonend ergens van profiteren
Français (French)
n. - avantage, bénéfice, (Sport) avantage (tennis, rugby)
v. tr. - avantager
idioms:
- have the advantage of avoir un avantage sur
- take advantage of tirer profit de, profiter de
- to good advantage à son profit, avantageusement
- to your advantage à votre avantage
- turn to one's advantage tirer parti de, tourner qch à son advantage
Deutsch (German)
n. - Vorteil
v. - nutzen, fördern, (einer Sache) dienen
idioms:
- have the advantage of (jmdm. gegenüber) in der besseren Position sein
- take advantage of ausnutzen
- to good advantage vorteilhaft
- to your advantage zu Ihrem Vorteil
- turn to one's advantage in einen Vorteil wandeln
Ελληνική (Greek)
n. - πλεονέκτημα, αβαντάζ, όφελος, ωφέλεια, υπεροχή, κέρδος, προτέρημα
idioms:
- take advantage of εκμεταλλεύομαι, επωφελούμαι, καταχρώμαι, εξαπατώ, αποπλανώ
- to good advantage με κέρδος
- to your advantage προς όφελός σου, για το καλό σου
- turn to one's advantage επωφελούμαι από, μεταστρέφω σε όφελός μου
idioms:
- take advantage of approfittare di, sfruttare
- to good advantage nella luce migliore
- to your advantage a tuo/vostro vantaggio
- turn to his advantage mettere a suo profitto
Português (Portuguese)
n. - vantagem (f), superioridade (f), circunstância (f) favorável, benefício (m)
idioms:
- take advantage of aproveitar, tirar partido ou vantagem
- to good advantage destacar as melhores características
- to your advantage para sua vantagem
- turn to his advantage explorar algo para seu benefício
Русский (Russian)
преимущество
idioms:
- take advantage of воспользоваться
- to good advantage на пользу дела
- to your advantage в твою пользу
- turn to his advantage повернуть в свою пользу
Español (Spanish)
n. - ventaja, beneficio, provecho
v. tr. - adelantar, beneficiar, promover
idioms:
- have the advantage of tener la ventaja de, contar con la ventaja de
- take advantage of aprovecharse de, sacar ventaja de, valerse de
- to good advantage para provecho de
- to your advantage a su favor, para su bien
- turn to one's advantage dar vuelta un suceso a nuestro favor
Svenska (Swedish)
n. - fördel, företräde, övertag
中文（简体）(Chinese (Simplified))
优势, 优点, 有利条件, 利益, 有利于, 使处于优势, 有助于
idioms:
- take advantage of 利用, 占...的便宜, 欺骗
- to good advantage 使优点突出
- to your advantage 对你有利
- turn to one's advantage 使...转为有利
中文（繁體）(Chinese (Traditional))
n. - 優勢, 優點, 有利條件, 利益
v. tr. - 有利於, 使處於優勢, 有助於
idioms:
- take advantage of 利用, 占...的便宜, 欺騙
- to good advantage 使優點突出
- to your advantage 對你有利
- turn to one's advantage 使...轉為有利
한국어 (Korean)
n. - 유리, 이익, 강점, 듀스 후 1점의 득점
v. tr. - 이롭게 하다
idioms:
- take advantage of ~을 이용하다, 허를 찌르다, 유혹하다
- to good advantage 매우 유리하게
- to your advantage 너에게 유리한
- turn to one's advantage 유리하게 이끌다
日本語 (Japanese)
n. - 有利な点, 利点, 優位, 利益, 便宜, 好都合, アドバンテージ, 優越
v. - 利する
idioms:
- take advantage of 利用する, …に付け込む
- to your advantage 有利に
العربيه (Arabic)
(الاسم) أفضليه, فائده, مصلحه إنقلب لصالحه
עברית (Hebrew)
n. - יתרון, תועלת, רווח
v. tr. - הועיל ל-, עזר ל-, קידם
If you are unable to view some languages clearly, click here.
Post a question - any question - to the WikiAnswers community:
Copyrights:
American Heritage Dictionary
The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.
Read more
Roget's Thesaurus
Roget's II: The New Thesaurus, Third Edition by the Editors of the American Heritage® Dictionary Copyright © 1995 byHoughton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.
Read more
Word Tutor
Copyright © 2004-present by eSpindle Learning, a 501(c) nonprofit organization. All rights reserved.
eSpindle provides personalized spelling and vocabulary tutoring online; sign up free. Read more
eSpindle provides personalized spelling and vocabulary tutoring online; sign up free. Read more
Random House Word Menu
© 2010 Write Brothers Inc. Word Menu is a registered trademark of the Estate of Stephen Glazier.
Write Brothers Inc.
All rights reserved.
Read more
Bradford's Crossword Solver's Dictionary
Collins Bradford's Crossword Solver's Dictionary © Anne Bradford, 1986, 1993, 1997, 2000, 2003, 2005, 2008
HarperCollins Publishers
All rights reserved.
Read more
Wikipedia on Answers.com
This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article Advantage (cryptography).
Read more
