Cryptography Advanced Encryption Standard AES Tutorial,fips 197
Computer Security, Cryptography Advanced Encryption Standard AES,fips 197 The Advanced Encryption Standard (AES) specifies a FIPS-approved cryptographic algo...

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Cryptography Advanced Encryption Standard AES Tutorial,fips 197 - Video

Cryptography - CISSP Domain 07
This video talks about: 1.Introduction to Cryptography CISSP Domain 07 2.Objectives - Basic concepts within cryptography 3.Public and private key algorithms ...

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Cryptography - CISSP Domain 07 - Video

"Secret code" redirects here. For the Aya Kamiki album, see Secret Code.

Cryptography (or cryptology; from Greek , "hidden, secret"; and , graphein, "writing", or -, -logia, "study", respectively)[1] is the practice and study of techniques for secure communication in the presence of third parties (called adversaries).[2] More generally, it is about constructing and analyzing protocols that overcome the influence of adversaries[3] and which are related to various aspects in information security such as data confidentiality, data integrity, authentication, and non-repudiation.[4] Modern cryptography intersects the disciplines of mathematics, computer science, and electrical engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce.

Cryptography prior to the modern age was effectively synonymous with encryption, the conversion of information from a readable state to apparent nonsense. The originator of an encrypted message shared the decoding technique needed to recover the original information only with intended recipients, thereby precluding unwanted persons to do the same. Since World WarI and the advent of the computer, the methods used to carry out cryptology have become increasingly complex and its application more widespread.

Modern cryptography is heavily based on mathematical theory and computer science practice; cryptographic algorithms are designed around computational hardness assumptions, making such algorithms hard to break in practice by any adversary. It is theoretically possible to break such a system but it is infeasible to do so by any known practical means. These schemes are therefore termed computationally secure; theoretical advances, e.g., improvements in integer factorization algorithms, and faster computing technology require these solutions to be continually adapted. There exist information-theoretically secure schemes that provably cannot be broken even with unlimited computing poweran example is the one-time padbut these schemes are more difficult to implement than the best theoretically breakable but computationally secure mechanisms.

Cryptology-related technology has raised a number of legal issues. In the United Kingdom, additions to the Regulation of Investigatory Powers Act 2000 require a suspected criminal to hand over his or her decryption key if asked by law enforcement. Otherwise the user will face a criminal charge.[5] The Electronic Frontier Foundation (EFF) was involved in a case in the United States which questioned whether requiring suspected criminals to provide their decryption keys to law enforcement is unconstitutional. The EFF argued that this is a violation of the right of not being forced to incriminate oneself, as given in the fifth amendment.[6]

Until modern times cryptography referred almost exclusively to encryption, which is the process of converting ordinary information (called plaintext) into unintelligible text (called ciphertext).[7] Decryption is the reverse, in other words, moving from the unintelligible ciphertext back to plaintext. A cipher (or cypher) is a pair of algorithms that create the encryption and the reversing decryption. The detailed operation of a cipher is controlled both by the algorithm and in each instance by a "key". This is a secret (ideally known only to the communicants), usually a short string of characters, which is needed to decrypt the ciphertext. A "cryptosystem" is the ordered list of elements of finite possible plaintexts, finite possible cyphertexts, finite possible keys, and the encryption and decryption algorithms which correspond to each key. Keys are important, as ciphers without variable keys can be trivially broken with only the knowledge of the cipher used and are therefore useless (or even counter-productive) for most purposes. Historically, ciphers were often used directly for encryption or decryption without additional procedures such as authentication or integrity checks.

In colloquial use, the term "code" is often used to mean any method of encryption or concealment of meaning. However, in cryptography, code has a more specific meaning. It means the replacement of a unit of plaintext (i.e., a meaningful word or phrase) with a code word (for example, wallaby replaces attack at dawn). Codes are no longer used in serious cryptographyexcept incidentally for such things as unit designations (e.g., Bronco Flight or Operation Overlord)since properly chosen ciphers are both more practical and more secure than even the best codes and also are better adapted to computers.

Cryptanalysis is the term used for the study of methods for obtaining the meaning of encrypted information without access to the key normally required to do so; i.e., it is the study of how to crack encryption algorithms or their implementations.

Some use the terms cryptography and cryptology interchangeably in English, while others (including US military practice generally) use cryptography to refer specifically to the use and practice of cryptographic techniques and cryptology to refer to the combined study of cryptography and cryptanalysis.[8][9] English is more flexible than several other languages in which cryptology (done by cryptologists) is always used in the second sense above. In the English Wikipedia the general term used for the entire field is cryptography (done by cryptographers).

The study of characteristics of languages which have some application in cryptography (or cryptology), i.e. frequency data, letter combinations, universal patterns, etc., is called cryptolinguistics.

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Cryptography - Wikipedia, the free encyclopedia

cryptography (krptg'rf) [Gr.,=hidden writing], science of secret writing. There are many devices by which a message can be concealed from the casual reader, e.g., invisible writing, but the term cryptography strictly applies to translating messages into cipher or code. The science of breaking codes and ciphers without a key is called cryptanalysis. Cryptology is the science that embraces both cryptography and cryptanalysis. In enciphering, each letter of the message is replaced by another letter or figure; in encoding, syllables, words, or whole sentences are treated. The code is the agreed upon set of rules whereby messages are converted from one form to another. The beginnings of cryptography can be traced to the hieroglyphs of early Egyptian civilization (c.1900 B.C.). Ciphering has always been considered vital for diplomatic and military secrecy; the Bible is replete with examples of ciphering, and many figures throughout history have written in ciphers, including Julius Caesar, Charlemagne, Alfred the Great, Mary Queen of Scots, and Louis XIV. Francis Bacon's celebrated biliteral cipher (1605) was an arrangement of the letters a and b in five-letter combinations, each representing a letter of the alphabet. This code illustrates the important principle that a code employing only two different signs can be used to transmit information. In the 20th cent. mathematical theory and computer science have both been applied to cryptanalysis. As the science of cryptology becomes increasingly sophisticated, most nations have found it necessary to develop special governmental bureaus to handle diplomatic and military security, e.g., the National Security Agency in the United States. The widespread use of computers and data transmission in commerce and finance is making cryptography very important in these fields as well. Recent successes in applying certain aspects of computer science to cryptography seem to be leading to more versatile and more secure systems in which encryption is implemented with sophisticated digital electronics. Industry and the U.S. government, however, have argued over who will have ultimate control over data encryption and, as a result, over government access to encrypted private transmissions.

Bibliography

See H. Gaines, Cryptanalysis (1956); J. R. Wolfe, Secret Writing (1970); D. Denning, Cryptography and Data Security (1982); C. A. Deavors and L. Kruh, Machine Cryptography and Modern Cryptoanalysis (1985); D. Kahn, The Codebreakers (rev. ed. 1996); S. Singh, The Code Book (1999).

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cryptography: Definition from Answers.com

Main TERM C The art of protecting information by transforming it (encrypting it) into an unreadable format, called cipher text. Only those who possess a secret key can decipher (or decrypt) the message into plain text. Encrypted messages can sometimes be broken by cryptanalysis, also called codebreaking, although modern cryptography techniques are virtually unbreakable.

As the Internet and other forms of electronic communication become more prevalent, electronic security is becoming increasingly important. Cryptography is used to protect e-mail messages, credit card information, and corporate data. One of the most popular cryptography systems used on the Internet is Pretty Good Privacy because it's effective and free.

Cryptography systems can be broadly classified into symmetric-key systems that use a single key that both the sender and recipient have, and public-key systems that use two keys, a public key known to everyone and a private key that only the recipient of messages uses.

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What is cryptography? - A Word Definition From the ...

In the world of cybersecurity, Bruce Schneier is an unusually accessible voice for those of us who feel we dont quite understand whats going on. The author of 12 books, and a prolific blogger and speaker, Schneier helped the Guardian go through the top-secret documents from the U.S. National Security Agency leaked by Edward Snowden last year.

So he knows what hes talking about when discussing the import of Snowdens revelations, which he did Wednesday at the Real World Cryptography Workshop, held in the gothic Great Hall at City University of New York in upper Manhattan.

Honestly, my favorite thing about these documents is the code names, he said, to laughter from the mostly male, relatively young crowd. He rattled them off: FoxAcid, Ferret Cannon, United Rake, Blackheart, Blarney, Quantum. His vote for the stupidest: EgotisticalGiraffe, an exploit aimed at the Firefox browser.

Schneier quickly turned serious. Were faced with a government agency on a quixotic mission to collect everything, from chats in online gaming worlds like Second Life, to data passed from air to ground when you use a laptop on a plane, he said. And while the NSA may have turned the Internet into a giant surveillance platform, this is just what every nation state is doing.

We actually dont know whats broken, he said. I get asked all the time, can I trust this, can I trust that? The truth is we dont know, and we have to move forward.

There is some good news in the Snowden documents, Schneier said, and thats that encryption still works. The NSA has often been able to get around it because other parts of the equation, like software or hardware, are insecure. Still, most current cryptography gives the NSA some trouble, and a lot of the data that the NSA snags isnt encrypted. That means were making it too easy for the NSA to pursue its collect everything mania. Schneiers solution: encrypt everything we can, from the cloud to cell phones.

Schneiers not advocating stopping the NSA from targeted spyingthered be no debate right now if Snowdens documents had shown the NSA spying on North Korea and the Taliban. He just wants to make it cheaper for the NSA to target the bad guys than for them to target everybody and get the bad guys incidentally.

Above all, we have to shift the terms of the debate, he said. Defenders of the NSA cast us in an arms raceif we dont do it, others will. Thats absolutely the wrong argument, he said. Its not us vs. them, its security vs. insecurity. Either we build an Internet that is secure for all users, or an Internet that is vulnerable to all attackers.

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To Foil NSA Spies, Encrypt Everything