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Canonical XML
Canonical XML is a normal form of XML, intended to allow relatively simple comparison of pairs of XML documents for equivalence; for this purpose, the Canonical XML transformation removes non-meaningful differences between the documents. Any XML document can be converted to Canonical XML. For example, XML permits whitespace to occur at various points within start-tags, and attributes to be specified in any order. Such differences are seldom if ever used to convey meaning, and so these forms are generally considered equivalent: <p class="a" secure="1"> <p secure = "1" class='a' > In converting an arbitrary XML document to Canonical XML, attributes are encoded in a normative order (alphabetical by name), and with normative spacing and quoting (though with all namespace declarations placed ahead of regular attributes, and namespaced attributes sorted by namespace rather than prefix or qualified name). Thus, the second form above would be converted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Canonical Form
In mathematics and computer science, a canonical, normal, or standard form of a mathematical object is a standard way of presenting that object as a mathematical expression. Often, it is one which provides the simplest representation of an object and allows it to be identified in a unique way. The distinction between "canonical" and "normal" forms varies from subfield to subfield. In most fields, a canonical form specifies a ''unique'' representation for every object, while a normal form simply specifies its form, without the requirement of uniqueness. The canonical form of a positive integer in decimal representation is a finite sequence of digits that does not begin with zero. More generally, for a class of objects on which an equivalence relation is defined, a canonical form consists in the choice of a specific object in each class. For example: *Jordan normal form is a canonical form for matrix similarity. *The row echelon form is a canonical form, when one considers as equ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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UTF-8
UTF-8 is a character encoding standard used for electronic communication. Defined by the Unicode Standard, the name is derived from ''Unicode Transformation Format 8-bit''. Almost every webpage is transmitted as UTF-8. UTF-8 supports all 1,112,064 valid Unicode code points using a variable-width encoding of one to four one- byte (8-bit) code units. Code points with lower numerical values, which tend to occur more frequently, are encoded using fewer bytes. It was designed for backward compatibility with ASCII: the first 128 characters of Unicode, which correspond one-to-one with ASCII, are encoded using a single byte with the same binary value as ASCII, so that a UTF-8-encoded file using only those characters is identical to an ASCII file. Most software designed for any extended ASCII can read and write UTF-8, and this results in fewer internationalization issues than any alternative text encoding. UTF-8 is dominant for all countries/languages on the internet, with 99% global ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Newline
A newline (frequently called line ending, end of line (EOL), next line (NEL) or line break) is a control character or sequence of control characters in character encoding specifications such as ASCII, EBCDIC, Unicode, etc. This character, or a sequence of characters, is used to signify the end of a line (text file), line of text and the start of a new one. History In the mid-1800s, long before the advent of teleprinters and teletype machines, Morse code operators or telegraphists invented and used Prosigns for Morse code, Morse code prosigns to encode white space text formatting in formal written text messages. In particular, the International Morse code, Morse prosign (mnemonic break text), represented by the concatenation of literal textual Morse codes "B" and "T" characters, sent without the normal inter-character spacing, is used in Morse code to encode and indicate a ''new line'' or ''new section'' in a formal text message. Later, in the age of modern teleprinters, st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Hexadecimal
Hexadecimal (also known as base-16 or simply hex) is a Numeral system#Positional systems in detail, positional numeral system that represents numbers using a radix (base) of sixteen. Unlike the decimal system representing numbers using ten symbols, hexadecimal uses sixteen distinct symbols, most often the symbols "0"–"9" to represent values 0 to 9 and "A"–"F" to represent values from ten to fifteen. Software developers and system designers widely use hexadecimal numbers because they provide a convenient representation of binary code, binary-coded values. Each hexadecimal digit represents four bits (binary digits), also known as a nibble (or nybble). For example, an 8-bit byte is two hexadecimal digits and its value can be written as to in hexadecimal. In mathematics, a subscript is typically used to specify the base. For example, the decimal value would be expressed in hexadecimal as . In programming, several notations denote hexadecimal numbers, usually involving a prefi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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CDATA
The term CDATA, meaning character data, is used for distinct, but related, purposes in the markup languages SGML and XML. The term indicates that a certain portion of the document is general ''character data'', rather than non-character data or character data with a more specific, limited structure. CDATA sections in XML In an XML document or external entity, a CDATA section is a piece of element content that is marked up to be interpreted literally, as textual data, not as marked-up content. A CDATA section is merely an alternative syntax for expressing character data; there is no semantic difference between character data in a CDATA section and character data in standard syntax where, for example, "<" and "&" are represented by "<" and "&", respectively. Syntax and interpretation A CDATA section starts with the following sequence: All characters enclosed between these two sequences are interpreted as characters, not markup or entity references. Every cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Steganography
Steganography ( ) is the practice of representing information within another message or physical object, in such a manner that the presence of the concealed information would not be evident to an unsuspecting person's examination. In computing/electronic contexts, a computer file, message, image, or video is concealed within another file, message, image, or video. Generally, the hidden messages appear to be (or to be part of) something else: images, articles, shopping lists, or some other cover text. For example, the hidden message may be in invisible ink between the visible lines of a private letter. Some implementations of steganography that lack a formal shared secret are forms of security through obscurity, while key-dependent steganographic schemes try to adhere to Kerckhoffs's principle. The word ''steganography'' comes from Greek ''steganographia'', which combines the words ''steganós'' (), meaning "covered or concealed", and ''-graphia'' () meaning "writing". The fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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XML Signature
XML Signature (also called ''XMLDSig'', ''XML-DSig'', ''XML-Sig'') defines an XML syntax for digital signatures and is defined in the W3C recommendationbr>XML Signature Syntax and Processing Functionally, it has much in common with PKCS #7 but is more extensible and geared towards signing XML documents. It is used by various Web technologies such as SOAP, SAML, and others. XML signatures can be used to sign data–a resource–of any type, typically XML documents, but anything that is accessible via a URL can be signed. An XML signature used to sign a resource outside its containing XML document is called a detached signature; if it is used to sign some part of its containing document, it is called an enveloped signature; if it contains the signed data within itself it is called an enveloping signature. Structure An XML Signature consists of a Signature element in the http://www.w3.org/2000/09/xmldsig# namespace. The basic structure is as follows: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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Cryptography Standards
There are a number of standards related to cryptography. Standard algorithms and protocols provide a focus for study; standards for popular applications attract a large amount of cryptanalysis. Encryption standards * Data Encryption Standard (DES, now obsolete) * Advanced Encryption Standard (AES) * RSA the original public key algorithm * OpenPGP Hash standards * MD5 128-bit (obsolete) * SHA-1 160-bit (obsolete) * SHA-2 available in 224, 256, 384, and 512-bit variants * HMAC keyed hash * PBKDF2 Key derivation function (RFC 2898) Digital signature standards * Digital Signature Standard (DSS), based on the Digital Signature Algorithm (DSA) * RSA * Elliptic Curve DSA Public-key infrastructure (PKI) standards * X.509 Public Key Certificates Wireless Standards * Wired Equivalent Privacy (WEP), severely flawed and superseded by WPA * Wi-Fi Protected Access (WPA) better than WEP, a 'pre-standard' partial version of 802.11i * 802.11i a.k.a. WPA2, uses AES and other improvements o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |