O LEVEL- INTERNET TECHNOLOGY & WEB DESIGN

O LEVEL-PAPER 2nd -- M2-R4 :

INTERNET TECHNOLOGY & WEB DESIGN

THESE ARE THE QUESTIONS WHICH FREQUENTLY ASKED IN 

  LAST 10 YEARS -----

MIME

Multipurpose Internet Mail Extensions (MIME) is an Internet standard that helps extend the limited capabilities of email by allowing insertion of images, sounds and text in a message. It was proposed by Bell Communications in 1991, and the specification was originally defined in June 1992 for RFCs 1341 and 1342.

MIME was designed to extend the format of email to support non-ASCII characters, attachments other than text format, and message bodies which contain multiple parts. MIME describes the message content type and the type of encoding used with the help of headers. All manually composed and automated emails are transmitted through SMTP in MIME format. The association of Internet email with SMTP and MIME standards is such that the emails are sometimes referred to as SMTP/MIME email. The MIME standard defines the content types which are of prime importance in communication protocols like HTTP for the World Wide Web. The data are transmitted in the form of email messages through HTTP even though the data are not an email.

The features offered by MIME to email services are as follows:

• Support for multiple attachments in a single message

·         Support for non-ASCII characters

• Support for layouts, fonts and colors which are categorized as rich text.
• Support for attachments which may contain executables, audio, images and video files, etc.
• Support for unlimited message length.

MIME is extensible because it defines a method to register new content types and other MIME attribute values. The format of a message body is described by MIME using special header directives. This is done so that the email can be represented correctly by the client.

• MIME Version: The presence of MIME Version generally indicates whether the message is MIME formatted. The value of the header is 1.0 and it is shown as MIME-Version: 1.0. The idea behind this was to create more advanced versions of MIME like 2.0 and so on.
• Content-Type: This describes the data’s Internet media type and the subtype. It may consist of a ‘charset’ parameter separated by a semicolon specifying the character set to be used. For example: Content-Type: Text/Plain.
• Content-Transfer-Encoding: It specifies the encoding used in the message body.
• Content-Description: Provides additional information about the content of the message.
• Content-Disposition: Defines the name of the file and the attachment settings and uses the attribute 'filename'.

PKC

Public key cryptography (PKC) is an encryption technique that uses a paired public and private key (or asymmetric key) algorithm for secure data communication. A message sender uses a recipient's public key to encrypt a message. To decrypt the sender's message, only the recipient's private key may be used.

The two types of PKC algorithms are RSA, which is an acronym named after this algorithm's inventors: Rivest, Shamir and Adelman, and Digital Signature Algorithm (DSA). PKC encryption evolved to meet the growing secure communication demands of multiple sectors and industries, such as the military.

PKC is also known as public key encryption, asymmetric encryption, asymmetric cryptography, asymmetric cipher, asymmetric key encryption and Diffie-Hellman encryption.

PKC is a cryptographic algorithm and cryptosystem component implemented by a variety of internet standards, including Transport Layer Security (TLS), Pretty Good Privacy (PGP), GNU Privacy Guard (GPG), Secure Socket Layer (SSL) and Hypertext Transfer Protocol (HTTP) websites.

PKC facilitates secure communication through an insecure channel, which allows a message to be read by the intended recipient only. For example, A uses B's public key to encrypt a message to B, which can be decrypted using B's unique private key.

PKC maintains email privacy and ensures communication security while messages are in transit or stored on mail servers. PKC is also a DSA component used to authenticate a private key verifiable by anyone with authorized public key access, which validates message origin and sender. Thus, PKC facilitates confidentiality, data integrity, authentication and nonrepudiation, which form key information assurance (IA) parameters.

PKC is slower than secret key cryptography (or symmetric cryptography) methods, due to high computational requirements. Unlike symmetric cryptography, PKC uses a fixed buffer size, depending on particular and small data amounts, which may only be encrypted and not chained in streams. Because a broad range of possible encryption keys are used, PKC is more robust and less susceptible to third-party security breach attempts.

PKI

A public key infrastructure (PKI) supports the distribution and identification of public encryption keys, enabling users and computers to both securely exchange data over networks such as the Internet and verify the identity of the other party.

Without PKI, sensitive information can still be encrypted (ensuring confidentiality) and exchanged, but there would be no assurance of the identity (authentication) of the other party. Any form of sensitive data exchanged over the Internet is reliant on PKI for security.

Elements of PKI

A typical PKI consists of hardware, software, policies and standards to manage the creation, administration, distribution and revocation of keys and digital certificates. Digital certificates are at the heart of PKI as they affirm the identity of the certificate subject and bind that identity to the public key contained in the certificate.

A typical PKI includes the following key elements:

·         A trusted party, called a certificate authority (CA), acts as the root of trust and provides services that authenticate the identity of individuals, computers and other entities

·         A registration authority, often called a subordinate CA, certified by a root CA to issue certificates for specific uses permitted by the root

·         A certificate database, which stores certificate requests and issues and revokes certificates

A certificate store, which resides on a local computer as a place to store issued certificates and private keys