Protocols for Secure CommunicationsSecuring Internet Communication by using S-HTTP and SSLSecure Socket Layer (SSL) protocol is a protocol that uses public key encryption to secure channel over public Internet. A Secure Hypertext Transfer Protocol (denoted by S-HTTP) is an extended version of Hypertext Transfer Protocol that is provided for encryption of individual messages between client and server across Internet. S-HTTP is the basic application of SSL over HTTP which allows encryption of information passing between computers by protected and secure connections virtually.Securing E-mail by using S/MIME, PEM, and PGPThe Secure Multipurpose Internet Mail Extensions (S/MIME) is built on Multipurpose Internet Mail Extensions (MIME) encoding format by adding both encryption and authentication. Privacy Enhanced Mail (PEM) is given as standard to function with public key cryptosystems which uses 3DES symmetric key encryption. Pretty Good Privacy (PGP) technique uses IDEA Cipher for message encoding.Securing Web transactions with SET, SSL, and S-HTTPThe Secure Electronic Transactions (SET) is developed by MasterCard and VISA inThe year 1997 to provide protection from electronic payment fraud this uses DES to encrypt credicard information transfers. It provides security for Internet-based credit card transactions and credit card swipe systems in retail stores both.Securing TCP/IP with IPSeIPSec is an open source protocol to secure communications across any IP based network. IPSec is designed to protect integrity of data, user confidentiality, and authenticity at IP packet level.It combines several different cryptosystems: Diffie-Hellman, public key cryptography; digital certificates and bulk encryption algorithms. In the IPSec, IP layer security can be attained by use of application header (AH) protocol or encapsulating security payload (ESP) protocol.Securing TCP/IP with PGPPretty Good Privacy (PGP) is a hybrid cryptosystem designed in the year 1991 by Phil Zimmermann. It is the combined best available cryptographic algorithms to become open source de facto standard for encryption and authentication of electronic mail and file storage applications. It is low cost commercial PGP versions are available for several platforms. Table given below depicts PGP function.