User:Bobbylow/Cryptography
Cryptography (from the Greek word “hidden, secret” and “I write”) [1] is the practice and study of hiding information. Until recently, cryptography only referred to
History
The first encryption case occurred in ancient
As an example, the message,
“Hello Johnny”
Could be encrypted as
“Ifmmp Kmiooz”
One thing to keep in mind is that the letter encrypted has to be followed by the next letter in the alphabet so “e” has to follow up with “f,” so as to maintain some sort of order.
This cipher is known as
Over time, however, people began to set up pre-determined word lengths as to make the substitution cipher harder to crack, so for example…
“Hello Johnny”
Could now be encrypted as
“if mmpk miooz”
The main classical type is; however,
“hi John” becomes “ih ojnh”
Encryption attempts to ensure secrecy in communications, especially with spies, military leaders and diplomats. However, encryption does not necessarily protect the information from harm as it can reveal statistical information about the plaintext, which can be used to crack it. In the 9th century,
Modern day study of cryptography
Cryptography and be divided into 5 different studies
Symmetric-key cryptography
Symmetric-key Cryptography: This refers to the sender and receiver receiving the same key – which is the basis of control behind the algorithm for the cipher. The two main topics related to this type of crack are block ciphers – a cipher that inputs information, while using the block as a middleman and outputs the same information in an encrypted form and steam ciphers – which is an advanced form of block cipher in that it does the same thing but also does it faster and use lower capacity to perform it. With the added speed comes added risk however and steam cipher is the more risky one to use.
Public-key cryptography
Public-Key Cryptography: This form of cryptography acts in a different way in which the key used to encrypt it is different from the key used to decrypt it. A public key, one known to the public is known while a private key, the secret key, is unknown. The public key may be used to encrypt it but only the public key can be used to decrypt it.
File:Public-key cryptography image.png #10
Cryptanalysis
Cryptoanalysis: This is the study of obtaining the meaning of encrypted information, without access to the secret information on how to crack it. This is basically the major form of cracking the code, which involves finding the secret key
Cryptographic primitives
Cryptoanalysis: This is the study of obtaining the meaning of encrypted information, without access to the secret information on how to crack it. This is basically the major form of cracking the code, which involves finding the secret key
File:Cryptographic Primitives image.gif #11
Cryptosystems
Cryptographic Primitives: This term is used to describe the process of transforming algorithms with basic cryptographic properties and their associates to other cryptographic problems. This is mainly used to build computer security systems and to counter the threats of cryptographic attacks.
File:Cryptographic systems image.gif #12
Advantages and disadvantages
Just like any other program, cryptographic has been able to provide good results and bad consequences.
Advantages:
- Added protection for uses such as passwordsand buying stuff online
- Automated security programs for electronic systems
- As cryptographic ways improve, so do computers and so do consumer lives with it
- Puzzles like crosswords
- Constantly improving new ways and technologies to fight negative cryptography
Disadvantages:
- Widespread hackings
- Internet spam
- Malicious viruses
- Keyloggersand other programs that try to steal valuable information
- Bombs and other physical devices that threaten society
- Secret locations that may be encrypted since its secrecy is paramount to the success of terrorist attacks
Controversy
Just like any other topic, there has been a load of controversy surrounding cryptographic.
Matters like
All of these represent legal issues on whether cryptography is legal or not to use freely. Because of its look into privacy, it may even be referred to as a treasonous offense.
Relationship to computer science
Computer science is the study of anything to do with computational devices and its uses. Cryptography may not have been related to computers in its early days but because of the tremendous dependence on computers nowadays, widespread programs have been created just to attack or defend a computer from hacks. Because of these very recent developments, computer science disciplines are widely associated with cryptography in ways that are beyond anything that was related to cryptography before. Because of the huge customer base with computers, almost anyone nowadays can be tracked through computers and so if computers are compromised, dangerous actions can happen and so, the relation of the two topics are very close.
Relationship to CSC104H
Cryptography relates to some topics associated in CSC104H; in particular, programming, security and the internet. Because of cryptography’s wide usage in computers in the form of Trojans, keyloggers and spam, computers are in danger of becoming increasingly attacked and so all three forms play a part in the protection or degradation of the computer.
See also
- Cryptography
- Topics in cryptography
- List of cryptographers
- Books on cryptography
- List of important publications in computer science#Cryptography
- List of open problems in computer science#Cryptography
- Cryptography Classification
References
1)"Cryptology (definition)". Merriam-Webster's Collegiate Dictionary (11th edition). Merriam-Webster. Retrieved on 2008-12-03
2)Oded Goldreich, Foundations of Cryptography, Volume 1: Basic Tools, Cambridge University Press, 2001,
3)Friedrich Ludwig Bauer, Decrypted secrets [electronic resource] : methods and maxims of cryptology, Springer, 2007, Retrieved on 2008-12-03
4)Bill Unruh, Cryptography, University of British Columbia Physics, 1998, Retrieved 2008-12-03 http://axion.physics.ubc.ca/crypt.html
5)Cryptography Introduction and guide, Cryptography World, 2004-2005, Retrieved 2008-12-03 http://www.cryptographyworld.com/
6)Cryptography, Trinity College Department of Computer Science, 2006-01-18, Retrieved 2008-12-03 http://starbase.trincoll.edu/~crypto/
7)Frequency Analysis (definition). Sound Seal. Retrieved 2008-12-03 www.soundseal.com/glossary.shtml
8)Cryptography, Wikipedia, 2008-11-18, Retrieved 2008-12-03 http://en.wikipedia.org/wiki/Cryptography#History_of_cryptography_and_cryptanalysis
9)http://www.cs.bham.ac.uk/~mdr/teaching/modules/security/lectures/symmetric-docs/Ofb_encryption.png (Symmetric-key cryptography image)
10)http://upload.wikimedia.org/wikipedia/commons/thumb/f/f9/Public_key_encryption.svg/525px-Public_key_encryption.svg.png (Public-key cryptography image)
11)http://upload.wikimedia.org/wikipedia/en/0/05/FIALKA-rotors-in-machine.jpg (Cryptanalysis image)
12)http://www.codeproject.com/KB/vista-security/CryptographyNextGenDemo/cng1.gif (Cryptographic Primitives image)
13)http://jya.com/t851.gif (Cryptographic systems image)
External links
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