Because much of the terminology of cryptology dates to a time when written messages were the only things being secured, the source information, even if it is an apparently incomprehensible binary stream of 1s and 0s, as in computer output, is referred to as the plaintext. As noted above, the secret information known only to the legitimate users is the key, and the transformation of the plaintext under the control of the key into a cipher (also called ciphertext) is referred to as encryption. The inverse operation, by which a legitimate receiver recovers the concealed information from the cipher using the key, is known as decryption.
The most frequently confused, and misused, terms in the lexicon of cryptology are code and cipher. Even experts occasionally employ these terms as though they were synonymous.
A code is simply an unvarying rule for replacing a piece of information (e.g., letter, word, or phrase) with another object, but not necessarily of the same sort; Morse code, which replaces alphanumeric characters with patterns of dots and dashes, is a familiar example. Probably the most widely known code in use today is the American Standard Code for Information Interchange (ASCII). Employed in all personal computers and terminals, it represents 128 characters (and operations such as backspace and carriage return) in the form of seven-bit binary numbersi.e., as a string of seven 1s and 0s. In ASCII a lowercase a is always 1100001, an uppercase A always 1000001, and so on. Acronyms are also widely known and used codes, as, for example, Y2K (for Year 2000) and COD (meaning cash on delivery). Occasionally such a code word achieves an independent existence (and meaning) while the original equivalent phrase is forgotten or at least no longer has the precise meaning attributed to the code worde.g., modem (originally standing for modulator-demodulator).
Ciphers, as in the case of codes, also replace a piece of information (an element of the plaintext that may consist of a letter, word, or string of symbols) with another object. The difference is that the replacement is made according to a rule defined by a secret key known only to the transmitter and legitimate receiver in the expectation that an outsider, ignorant of the key, will not be able to invert the replacement to decrypt the cipher. In the past, the blurring of the distinction between codes and ciphers was relatively unimportant. In contemporary communications, however, information is frequently both encoded and encrypted so that it is important to understand the difference. A satellite communications link, for example, may encode information in ASCII characters if it is textual, or pulse-code modulate and digitize it in binary-coded decimal (BCD) form if it is an analog signal such as speech. The resulting coded data is then encrypted into ciphers by using the Data Encryption Standard or the Advanced Encryption Standard (DES or AES; described in the section History of cryptology). Finally, the resulting cipher stream itself is encoded again, using error-correcting codes for transmission from the ground station to the orbiting satellite and thence back to another ground station. These operations are then undone, in reverse order, by the intended receiver to recover the original information.
In the simplest possible example of a true cipher, A wishes to send one of two equally likely messages to B, say, to buy or sell a particular stock. The communication must take place over a wireless telephone on which eavesdroppers may listen in. It is vital to As and Bs interests that others not be privy to the content of their communication. In order to foil any eavesdroppers, A and B agree in advance as to whether A will actually say what he wishes B to do, or the opposite. Because this decision on their part must be unpredictable, they decide by flipping a coin. If heads comes up, A will say Buy when he wants B to buy and Sell when he wants B to sell. If tails comes up, however, he will say Buy when he wants B to sell, and so forth. (The messages communicate only one bit of information and could therefore be 1 and 0, but the example is clearer using Buy and Sell.)
With this encryption/decryption protocol being used, an eavesdropper gains no knowledge about the actual (concealed) instruction A has sent to B as a result of listening to their telephone communication. Such a cryptosystem is defined as perfect. The key in this simple example is the knowledge (shared by A and B) of whether A is saying what he wishes B to do or the opposite. Encryption is the act by A of either saying what he wants done or not as determined by the key, while decryption is the interpretation by B of what A actually meant, not necessarily of what he said.
This example can be extended to illustrate the second basic function of cryptography, providing a means for B to assure himself that an instruction has actually come from A and that it is unalteredi.e., a means of authenticating the message. In the example, if the eavesdropper intercepted As message to B, he couldeven without knowing the prearranged keycause B to act contrary to As intent by passing along to B the opposite of what A sent. Similarly, he could simply impersonate A and tell B to buy or sell without waiting for A to send a message, although he would not know in advance which action B would take as a result. In either event, the eavesdropper would be certain of deceiving B into doing something that A had not requested.
To protect against this sort of deception by outsiders, A and B could use the following encryption/decryption protocol.
They secretly flip a coin twice to choose one of four equally likely keys, labeled HH, HT, TH, and TT, with both of them knowing which key has been chosen. The outcome of the first coin flip determines the encryption rule just as in the previous example. The two coin flips together determine an authentication bit, 0 or 1, to be appended to the ciphers to form four possible messages: Buy-1, Buy-0, Sell-1, and Sell-0. B will only accept a message as authentic if it occurs in the row corresponding to the secret key. The pair of messages not in that row will be rejected by B as non-authentic. B can easily interpret the cipher in an authentic message to recover As instructions using the outcome of the first coin flip as the key. If a third party C impersonates A and sends a message without waiting for A to do so, he will, with probability 1/2, choose a message that does not occur in the row corresponding to the key A and B are using. Hence, the attempted deception will be detected by B, with probability 1/2. If C waits and intercepts a message from A, no matter which message it is, he will be faced with a choice between two equally likely keys that A and B could be using. As in the previous example, the two messages he must choose between convey different instructions to B, but now one of the ciphers has a 1 and the other a 0 appended as the authentication bit, and only one of these will be accepted by B. Consequently, Cs chances of deceiving B into acting contrary to As instructions are still 1/2; namely, eavesdropping on A and Bs conversation has not improved Cs chances of deceiving B.
Clearly, in either example, secrecy or secrecy with authentication, the same key cannot be reused. If C learned the message by eavesdropping and observed Bs response, he could deduce the key and thereafter impersonate A with certainty of success. If, however, A and B chose as many random keys as they had messages to exchange, the security of the information would remain the same for all exchanges. When used in this manner, these examples illustrate the vital concept of a onetime key, which is the basis for the only cryptosystems that can be mathematically proved to be cryptosecure. This may seem like a toy example, but it illustrates the essential features of cryptography. It is worth remarking that the first example shows how even a child can create ciphers, at a cost of making as many flips of a fair coin as he has bits of information to conceal, that cannot be broken by even national cryptologic services with arbitrary computing powerdisabusing the lay notion that the unachieved goal of cryptography is to devise a cipher that cannot be broken.
Follow this link:
Cryptology | Definition, Examples, History, & Facts | Britannica
- Nexus Of Mathematics, Cryptography, Blockchain Will Redefine Technological Innovation Expert - New Telegraph Newspaper - May 15th, 2024
- What is the purpose of post-quantum cryptography? - Security Boulevard - March 21st, 2024
- Quantum Computing and Networking Poised to Revolutionize Cryptography - BroadbandBreakfast.com - March 21st, 2024
- TM Technologies and Quantum Resistant Cryptography Team Up to Increase Speed and Security of 5G/6G, Satellite ... - Yahoo Finance UK - March 5th, 2024
- What Is Moore's Law, And How Does It Impact Cryptography? - Blockchain Magazine - January 24th, 2024
- Cryptography 101: Key Principles, Major Types, Use Cases ... - Splunk - December 11th, 2023
- Federal agencies take 'most important' first step with inventorying cryptography ahead of quantum migration, OMB ... - FedScoop - December 11th, 2023
- What is Cryptography? - Cryptography Explained - AWS - January 30th, 2023
- What is Cryptography? Definition, Importance, Types | Fortinet - January 22nd, 2023
- What is cryptography? How algorithms keep information secret and ... - CSO - January 22nd, 2023
- What is Cryptography? Definition from SearchSecurity - January 22nd, 2023
- System.Security.Cryptography.CryptographicException: The payload was ... - December 28th, 2022
- NIST Action Will Heat Up Post-Quantum Cryptography Market: Report - TechNewsWorld - December 12th, 2022
- Global Encryption Day: Why quantum-safe cryptography is the future of cybersecurity - World Economic Forum - October 23rd, 2022
- Post-Quantum Cryptography: Anticipating Threats and Preparing the Future - ENISA - October 23rd, 2022
- Cracking the code of cryptography and life The Irish Times - The Irish Times - October 15th, 2022
- Dutch influence standards for post-quantum cryptography - ComputerWeekly.com - October 15th, 2022
- Castle Shield Holdings, LLC Updates the Post-Quantum Cryptography (PQC) Algorithms for Its Data-in-Motion Aeolus VPN Solution - Business Wire - October 15th, 2022
- Yale increases investment in blockchain research - Yale Daily News - October 15th, 2022
- OPPO joins the FIDO Alliance, accelerating the arrival of a new era of passwordless sign-ins - Yahoo Finance - October 15th, 2022
- It's Time To Trust Crypto. Here's Why. - Entrepreneur - October 15th, 2022
- Algorand (ALGO) on its journey to breach the $0.4 mark! - CryptoNewsZ - October 15th, 2022
- Crypto Hackers Gross Over $3 Billion From 125 Hacks so Far This Year Featured Bitcoin News - Bitcoin News - October 15th, 2022
- Bitt and IDEMIA: Winners of the G20 Central Bank Digital Currency TechSprint 2022 - Yahoo Finance - October 15th, 2022
- White House Releases First-Ever Comprehensive Framework for Responsible Development of Digital Assets - Lexology - October 15th, 2022
- The Web3 Foundation taps edX for free courses on blockchain and Polkadot - Cointelegraph - October 15th, 2022
- CoinGeek Weekly Livestream: Jad Wahab and Marcin Zarakowski discuss honest nodes and their role in Bitcoin - CoinGeek - October 15th, 2022
- What Is Cryptography? Definition & How It Works | Okta - October 7th, 2022
- What Is Cryptography in Cyber Security: Types, Examples & More - October 7th, 2022
- Decentralized Identifiers (DIDs) is Officially an Internet Standard, Says The World Wide Web Consortium (W3C) - bitcoinke.io - October 7th, 2022
- Cloudflares post-quantum cryptography protects almost a fifth of the internet - VentureBeat - October 7th, 2022
- Nobel Prize in Physics goes to scientists who paved the way for quantum computing - Space.com - October 7th, 2022
- The 2nd Annual Encryption Consulting Conference is Back! - PR Newswire - October 7th, 2022
- Quantum Computing And The Threat Posed To Bitcoin - The Dales Report - October 7th, 2022
- Cryptocurrency users with gambling affinity are more involved mentally and financially than non-gambling users - PsyPost - October 7th, 2022
- Cardano (ADA) and Algorand (ALGO) Are Two Blockchains To Watch Next Bull Cycle, Says Coin Bureau Here?... - The Daily Hodl - October 7th, 2022
- The Guardian view on the Rosetta Stone: a monument to code-breaking - The Guardian - October 7th, 2022
- Still think everything is awful? Here are three reasons for hope - Colorado Newsline - October 7th, 2022
- Sleep Disorders And Quantum Cryptography Win Big At The Breakthrough Prizes 2023 - IFLScience - September 29th, 2022
- Lecturer in Cryptography job with KINGS COLLEGE LONDON | 310005 - Times Higher Education - September 29th, 2022
- Microsoft venture fund M12 invests millions in advancing cryptography and 'smart contracts' - OnMSFT.com - September 29th, 2022
- Sectigo's Chief Strategy Officer and CISO Advisor David Mahdi Accepted To Fast Company Executive Board - StreetInsider.com - September 29th, 2022
- Fundamental Cryptography in Theory and Python - iProgrammer - September 21st, 2022
- Web Crypto API - Web APIs | MDN - Mozilla - September 21st, 2022
- Cryptomathic appoints Laurent Lafargue as CEO of the pioneer in cryptography - FinanceFeeds - September 21st, 2022
- Blockchain and POW are the leading technology behind Bitcoin. - Deadline News - September 21st, 2022
- NTT Research Names Takashi Goto Head of the Technology Promotion Team - Business Wire - September 21st, 2022
- Investigating the Use of Blockchain to Authenticate Data from the Statistics Canada Website - Statistique Canada - September 21st, 2022
- 6 Technological Innovations in the New York Sports Betting Industry - Qrius - September 21st, 2022
- EMVCo reports on the future of contactless payments - NFC World - September 13th, 2022
- Quantum eMotion to Present at the H.C. Wainwright 24th Annual Global Investment Conference in New York - Digital Journal - September 13th, 2022
- The emerging role of cybersecurity in the automotive sector - The Financial Express - September 13th, 2022
- Jack Dorseys Web5 is a solution to a problem thats already been solved - VentureBeat - September 5th, 2022
- What is Cryptography in security? What are the different types of ... - September 5th, 2022
- RKVST Launches RKVST Free and RKVST Team SaaS Supply Chain Integrity, Transparency and Trust Solution - Business Wire - September 5th, 2022
- The United States Is Behind the Curve on Blockchain - War on the Rocks - September 5th, 2022
- $3.7 Billion Worldwide Blockchain in Retail Industry to 2027 - Featuring Cognizant, Infosys and Oracle Among Others - ResearchAndMarkets.com -... - September 5th, 2022
- Research Fellow in Applied Cryptography And Data Security job with UNIVERSITY OF SURREY | 306274 - Times Higher Education - August 28th, 2022
- ASPG, Inc. Announces Release of CryptoZ, Innovative New z/OS Cryptography Reporting and Administration Sy - Benzinga - August 28th, 2022
- UN: monitoring the use of cryptography can make the Internet safer - The Cryptonomist - August 20th, 2022
- Keyfactor Named to the 2022 Inc. 5000 List for Third Consecutive Year and Recognized as the Fastest Growing PKI and Cryptography Leader in America -... - August 20th, 2022
- Cryptography 101: Giving a framework to the brimming blockchain businesses of India - Times of India - August 20th, 2022
- Godfather of Crypto expresses concerns over current state of blockchain privacy - CryptoSlate - August 20th, 2022
- Nine Benefits of FIDO Authentication | HYPR - Security Boulevard - August 20th, 2022
- Now That Authorities Have Sanctioned Tornado Cash, Is Bitcoin Next? - Bitcoin Magazine - August 20th, 2022
- Meet the world's first carbon-negative blockchain - wknd. - August 20th, 2022
- 'FutureFi': Crypto is transforming the green finance universe | Greenbiz - GreenBiz - August 20th, 2022
- Philippine Regulator Warns the Public of Engaging With Foreign Crypto Service Providers Regulation Bitcoin News - Bitcoin News - August 20th, 2022
- What Is Cryptography: Definition and Common Cryptography Techniques - August 12th, 2022
- What is Cryptography? Types of Algorithms & How Does It Work? - August 12th, 2022
- What is Cryptography? - Kaspersky - August 12th, 2022
- Former Google CEO: Bitcoin is a remarkable achievement of cryptography - The Cryptonomist - August 12th, 2022
- Protect your privacy with cybersecurity and cryptography - Geeky Gadgets - August 12th, 2022
- Saving Private Keys From The Courts - Bitcoin Magazine - August 12th, 2022
- NTT Research and NTT Corporation Engage in Breakthrough Research at Crypto 2022 - Business Wire - August 12th, 2022
- Can WhatsApp messages be secure and encryptedbut traceable at the same time? - EurekAlert - August 12th, 2022
- Why 2023 is the year of passwordless authentication - TechTarget - August 12th, 2022
- Sony unveils a new way to protect images from theft, manipulation - Popular Photography - August 12th, 2022
- Cameron Whitehead wins again, taking top honors in the CyberForce Program's Conquer the Hill Reign Edition Competition - EurekAlert - August 12th, 2022
- Criminals steal $4 million from Solana as theft trend hits its crypto blockchain - SC Media - August 12th, 2022