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In cryptography, encryption is the process of transforming information (referred to as plaintext) using an algorithm (called cipher) to make it unreadable to anyone except those possessing special knowledge, usually referred to as a key. The result of the process is encrypted information (in cryptography, referred to as ciphertext). In many contexts, the word encryption also implicitly refers to the reverse process, decryption (e.g. “software for encryption” can typically also perform decryption), to make the encrypted information readable again (i.e. to make it unencrypted).

Encryption has long been used by militaries and governments to facilitate secret communication. Encryption is now commonly used in protecting information within many kinds of civilian systems. For example, the Computer Security Institute reported that in 2007, 71% of companies surveyed utilized encryption for some of their data in transit, and 53% utilized encryption for some of their data in storage.[1] Encryption can be used to protect data "at rest", such as files on computers and storage devices (e.g. USB flash drives). In recent years there have been numerous reports of confidential data such as customers' personal records being exposed through loss or theft of laptops or backup drives. Encrypting such files at rest helps protect them should physical security measures fail. Digital rights management systems which prevent unauthorized use or reproduction of copyrighted material and protect software against reverse engineering (see also copy protection) are another somewhat different example of using encryption on data at rest.

Encryption is also used to protect data in transit, for example data being transferred via networks (e.g. the Internet, e-commerce), mobile telephones, wireless microphones, wireless intercom systems, Bluetooth devices and bank automatic teller machines. There have been numerous reports of data in transit being intercepted in recent years.[2] Encrypting data in transit also helps to secure it as it is often difficult to physically secure all access to networks.

Encryption, by itself, can protect the confidentiality of messages, but other techniques are still needed to protect the integrity and authenticity of a message; for example, verification of a message authentication code (MAC) or a digital signature. Standards and cryptographic software and hardware to perform encryption are widely available, but successfully using encryption to ensure security may be a challenging problem. A single slip-up in system design or execution can allow successful attacks. Sometimes an adversary can obtain unencrypted information without directly undoing the encryption. See, e.g., traffic analysis, TEMPEST, or Trojan horse.

One of the earliest public key encryption applications was called Pretty Good Privacy (PGP). It was written in 1991 by Phil Zimmermann and was purchased by Network Associates (now PGP Corporation) in 1997.

There are a number of reasons why an encryption product may not be suitable in all cases. First, e-mail must be digitally signed at the point it was created to provide non-repudiation for some legal purposes, otherwise the sender could argue that it was tampered with after it left their computer but before it was encrypted at a gateway. An encryption product may also not be practical when mobile users need to send e-mail from outside the corporate network.[3]

Contents

See also

Notes

  1. ^ Robert Richardson, 2008 CSI Computer Crime and Security Survey at 19. Online at http://i.cmpnet.com/v2.gocsi.com/pdf/CSIsurvey2008.pdf.
  2. ^ Fiber Optic Networks Vulnerable to Attack, Information Security Magazine, November 15, 2006, Sandra Kay Miller
  3. ^ http://www.enterprisenetworkingplanet.com/_featured/article.php/3792771/PGPs-Universal-Server-Provides-Unobtrusive-Encryption.htm.

References

  • Helen Fouché Gaines, “Cryptanalysis”, 1939, Dover. ISBN 0-486-20097-3
  • David Kahn, The Codebreakers - The Story of Secret Writing (ISBN 0-684-83130-9) (1967)
  • Abraham Sinkov, Elementary Cryptanalysis: A Mathematical Approach, Mathematical Association of America, 1966. ISBN 0-88385-622-0

External links


Simple English

Encryption is a method which allows information to be hidden so that it cannot be read without special knowledge or tools. Once this is done the information is encrypted. Decryption is a way to change an encrypted piece of information back into unencrypted form. This is called the decrypted form.

Examples

A simple kind of encryption for words is ROT13. In ROT13, letters of the alphabet are changed with each other using a simple pattern. For example, A changes to N, B changes to O, C changes to P, and so on. Each letter is "rotated" by 13 spaces. Using the ROT13 cipher, the words Simple English Wikipedia becomes Fvzcyr Ratyvfu Jvxvcrqvn. The ROT13 cipher is very easy to decrypt. Because there are 26 letters in the English alphabet, if a letter is rotated two times by 13 letters each time, the original letter will be obtained. So applying the ROT13 cipher a second time brings back the original text.

Most kinds of encryption are more complex. Some are made only for text. Others are made for binary computer files like pictures and music. Today, the encryption system used the most is RSA. Any computer file can be encrypted with RSA.

On the Internet

Encryption is used on the Internet. Web sites use encryption to protect private information. On the Internet, several encryption protocols are used, such as Secure Sockets Layer (SSL), IPsec, and SSH. They use the RSA encryption system and others. The protocol for protected web browsing is called HTTPS. Mostly URL encryption contain MD5 Algorithm. Various alogorithm are available on the internet/market depending upon the need.

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