|
|
| Line 1: |
Line 1: |
| {{unreferenced|date=December 2011}}
| | Hello. Allow me introduce the writer. Her title is Emilia Shroyer but it's not the most female name out there. To collect badges is what her family and her enjoy. He used to be unemployed but now he is a meter reader. South Dakota is her birth place but she requirements to move because of her family.<br><br>Also visit my web page; [http://www.webmdbook.com/index.php?do=/profile-11685/info/ over the counter std test] |
| '''Encryption software''' is [[software]] whose main task is [[encryption]] and [[decryption]] of data, usually in the form of files on (or sectors of) [[hard drive]]s and [[removable media]], [[email]] messages, or in the form of packets sent over [[computer network]]s.
| |
| | |
| ==Encryption==
| |
| Encryption software executes an [[algorithm]] that is designed to [[encrypt]] computer data in such a way that it cannot be recovered without access to the key. Software encryption is a fundamental part of all aspects of modern computer communication and file protection and may include features like file shredding.
| |
| | |
| The purpose of encryption is to prevent third parties from recovering the original information. This is particularly important for sensitive data like credit card numbers.
| |
| | |
| == Encryption choices ==
| |
| | |
| Many encryption algorithms exist. The more popular options were submitted to the National Institute of Standards and Technology or [[NIST]] for the '''Advanced Encryption Standard''' ([[Advanced Encryption Standard|AES]]) competition. The winner, [[Rijndael]], got 86 votes while [[Serpent (cipher)|Serpent]] got 59 votes, [[Twofish]] 31 votes, [[RC6]] 23 votes and [[MARS (cryptography)|MARS]] 13 votes. NIST chose Rijndael as its standard. Serpent and Rijndael are in fact somewhat similar; the main difference is that Rijndael is faster (having fewer rounds) but Serpent is more secure{{Citation needed|date=October 2009}}.
| |
| | |
| == Choosing encryption ==
| |
| | |
| There are several factors that affect the choice of an encryption algorithm including speed and security. The simplest method would be an [[XOR]] operation, with a constant value <math>k</math>, of each byte of plain text <math>b</math>, to produce a cipher value <math>c</math>.
| |
| | |
| <math>b\, \mathrm{XOR}\, k = c</math>
| |
| | |
| Ciphers can be categorized into two general types: [[Public-key cryptography|public key]] ciphers and [[symmetric key algorithm|symmetric key]] ciphers.
| |
| | |
| Public key systems are based upon algorithms that are at least strongly believed to be "one-way" operations. That is, encryption with one member of a key pair is only easily reversed (decrypted) using the other member of the pair. Further, one member of the pair (the public key) cannot be easily used to determine the other (the private key). Provided the problems posed by the system to cryptanalyst are effectively unsolvable, the system is effectively secure. Such systems are used for key exchanges (for subsequent use of symmetric key ciphers), digital signatures and the like.
| |
| | |
| Symmetric key ciphers (also referred to as secret key ciphers) are called such because the same key is used for both encryption and decryption. Thus, in order for messages encrypted with a symmetric key cipher to remain secure, the key used must remain secret. Symmetric key ciphers can be further subdivided into [[stream cipher]]s and [[block cipher]]s.
| |
| | |
| Stream ciphers typically encrypt plaintext a bit or byte at a time, and are most commonly used to encipher real-time communications, such as audio and video information. The key is used to establish the initial state of a key-stream generator, and the output of that generator is used to encrypt the plaintext.
| |
| | |
| Block cipher algorithms encrypt blocks of bytes of plaintext a block at a time. The Advanced Encryption Standard algorithm (AES - derived from the Rijndael cipher algorithm) is a block cipher that processes 16 bytes at a time, while its predecessor, the Data Encryption Standard algorithm (DES) encrypted blocks of eight bytes.
| |
| | |
| A common mistake made by amateur cryptographers is the assumption that because the method is secret, the cipher is secure. This is not usually true. Many "home grown" encryption algorithms reveal the key quite easily when fed a string of identical bytes (e.g., [[Null character|null]]s).
| |
| | |
| The purpose of disseminating an encryption method is to allow the community to evaluate it. If it is indeed secure, then its power lies in the fact that its method has been subjected to scrutiny and found to be sound, not that it is secret.
| |
| | |
| == Applications ==
| |
| Encryption can be applied to data in many ways. Common categories are:
| |
| | |
| * [[Disk encryption software]] (also known as [[OTFE]] software)
| |
| * [[File/folder encryption]]
| |
| * [[Database encryption]]
| |
| * [[Communication encryption software]]
| |
| | |
| Network traffic encryption tools
| |
| *[http://www.securityfocus.com/tools/category/30 Generic]
| |
| *[http://seifried.org/security/cryptography/crypto-book/chapter-14.html IPSec based]
| |
| | |
| Each of these categories define the range and location of the data to be encrypted, but the process is the same for each.
| |
| | |
| ==See also==
| |
| | |
| {{Portal|Cryptography}}
| |
| | |
| * [[Cold boot attack]]
| |
| * [[Disk encryption]]
| |
| * [[Password manager]]
| |
| * [[Single sign-on]]
| |
| | |
| ==External links==
| |
| * {{dmoz|Computers/Security/Products_and_Tools/Cryptography/File_Encryption}}
| |
| | |
| {{Cryptographic software}}
| |
| | |
| <!-- Categories -->
| |
| [[Category:Cryptographic software]]
| |
Hello. Allow me introduce the writer. Her title is Emilia Shroyer but it's not the most female name out there. To collect badges is what her family and her enjoy. He used to be unemployed but now he is a meter reader. South Dakota is her birth place but she requirements to move because of her family.
Also visit my web page; over the counter std test