ENCRYPTION AND Cryptography

Cryptography has evolved a long time, when people want information that he sent not to 'read' by parties not interested. Traditionally known as the two mechanisms cryptography, private key or public key. DES (data encryption standard) used by Kerberos to use private-key system. RSA (Rivest Shamir Addleman) implement public-key system. One of the contributors RSA, Ron Rivest and then make MD4 (message digest function # 4) which is used by S / Key his TIS-FWTK. Optimization and crossbreed between the two traditional methods are giving birth PGP (Pretty Good Privacy). Discussion of the DES, RSA, or PGP is a separate book and not in place is disclosed here. But clearly,
the private-key system is characterized by the encrypt-decrypt the keys are identical, while the public-key systems, this process is done with two keys: public key to encrypt and decrypt secret key for this key which both generated and have relationships close through a mathematical algorithm. Because the mathematical processes required in advance, the speed of public-key systems can be thousands of times slower than equivalent private-key algorithm, although on the other hand offers better protection. The exploitation of the advantages and disadvantages of public and private key system is PGP, which is done for data transmission-private key system with the session-key so that it runs fast, while the transmission of session-key of his own using public-key.
With encryption, the information we send to a network through another network of safety doubts (the Internet), relatively more secure. Encryption between networks is causing a 'thief' must try a little harder to get illegal information he expected. There are several opportunities for the implementation of encryption, namely: at the application level, data-link level and network level.
Application-level encryption requires the use of client-server software special. In accordance with the OSI reference model, encryption of data-link is only valid for point to point connection, such as encryption system on a phone modem. While encryption network level (network layer) is applied on the router or other equipment adjacent to the tissue on both sides. Optimization of the interests and security policies carried out by adjusting the type / part of the IP packet to be encrypted, adjustments to the firewall architecture and, consequently, the effectiveness of key distribution, encryption, etc.. In the future, where technology VLAN (Virtual LAN) is estimated to be the primary choice for Intranet (enterprisewide), the use of network-level encryption has become so important. Perhaps equally important to state that while a company is 'forced' to use the internet as a route for transmission of sensitive information between the central office with other branches in hemisphere earth.