Internet - Digital Envelope
Cryptography and the Internet
The widespread penetration and adoption of the Internet has opened up myriad of possibilities, making newer and sophisticated forms of communication, collaboration and information sharing and dissemination possible. However, this trend has also made the task of ensuring the security and privacy of the computer networks critically important. Cryptography plays an essential role in providing security of computer networks, and today cryptography is incorporated in various aspects of the Internet. Without such security measures, even simple credit card transactions would prove to be disastrous.
Let us look at some of the Internet related mechanisms in which cryptography plays an important role.
Secure HTTP (S-HTTP)
Secure HTTP (S-HTTP) is a security extension to the HTTP protocol, and it allows secure transactions over the Web by allowing messages to be encapsulated and have security transformations applied to it. It provides a wide range of cryptographic mechanisms to be used for providing privacy and authentication, and is therefore not tied to any particular cryptographic algorithm or system.
Secure Sockets Layer (SSL)
Secure Sockets Layer (SSL) is another technology for transmitting secure communications over the World Wide Web. SSL was developed by Netscape Communications in 1994 to provide security and privacy to Internet sessions. It provides both server-side and client-side authentication. A SSL client and the server establish a secure connection by a handshaking procedure. During the course of this process, the server submits a digital certificate (electronic document containing identity information) to the client and states its preference for the cipher to be used for communication. The client then generates a secret key and submits it to the server, properly encrypted using the server's public key. The server then decrypts this message using its private key and obtains the secret key, and authenticates itself to the client by sending it a message encrypted with the secret key it just received. Once this is done, further communication takes place with the data encrypted using this private key.
A typical email message travels to its intended destination in a fragmented route. There are lots of chances for the message to be viewed while it travels along the network. This is clearly not a favorable situation, as often sensitive information such as username and passwords are sent via email. Therefore, email encryption allows ordinary people to communicate securely without their messages intercepted and read by a third person with a malicious intent. Many products offer secure e-mail either as with Pretty Good Privacy (PGP) or by using a protocol such as Secure MIME (S/MIME). S/MIME provides authentication, checks for message integrity and non-repudiation of origin and data security for electronic messaging applications.
- Introduction to cryptography, Part 4: Cryptography on the Internet.
- Cryptography and the Internet by Steven M. Bellovin.
- Cryptography and the Internet by Kevin S. McCurley.
- An Overview of SHTTP by Adam Shostack.
- Image credit: stock.xchng - Computer (photo by duchesssa)