WHAT IS INTERNET
The Internet, sometimes called simply “the Net,” is a worldwide system of computer networks — a network of networks in which users at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to users at other computers). It was conceived by the Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was first known as the ARPANET. The original aim was to create a network that would allow users of a research computer at one university to “talk to” research computers at other universities. A side benefit of ARPANet’s design was that, because messages could be routed or rerouted in more than one direction, the network could continue to function even if parts of it were destroyed in the event of a military attack or other disaster.
Today, the Internet is a public, cooperative and self-sustaining facility accessible to hundreds of millions of people worldwide. It is used by many as the primary source of information consumption, and fueled the creation and growth of its own social ecosystem through social media and content sharing. Furthermore,e-commerce or online shopping, has become one of the largest uses of the Internet.
A brief history of the internet
Major breakthroughs 
- October 29, 1969: ARPANET (later renamed internet) created a successful connection between University of California Los Angeles and the Stanford Research Institute.
- Late 1960s: Libraries automate and network catalogs independent of ARPANET.
- 1970s: Transport Control Protocol and Internet Protocol (TCP/IP) is established, allowing for internet technology to mature. The invention of these protocols helped to standardize how information was sent and received over the web.
- 1986: National Science Foundation funded NSFNET, which is the 56 Kbps backbone of the internet. There were commercial restrictions in place at this time because federal funds were being used to run and maintain it.
- 1991: User-friendly internet interface was created.
- July 1992: Delphi became the first national commercial online service to offer internet access.
- May 1995: All commercial use limitations on the internet disappear. This allowed the internet to diversify and grow rapidly.
- 1997: WiFi was invented.
- 1998: Windows 98 hit the market.
- 2007: Widespread smartphone adoption.
- 2009: 4G network is introduced.
- Today: 3 billion people use the internet. 
- 2030: 7.5 billion projected internet users and 500 billion devices connected to the internet. 
How Does the Internet Work: A Step-by-Step Pictorial
The internet plays a significant role in our daily lives
- In the year 2000, only 52% of US adults used the internet 
- In 2018, that number jumped to 89%
- In 2013, US adults who didn’t use broadband internet at home but owned smartphones was just 8%
- In 2018, that number increased to 20%
To fully understand how the internet works and how we got here, we’ll need to start from the beginning.
How does the internet work?
When you type in a web address into your browser…
- Example: Google.com becomes 22.214.171.124
What Is the World Wide Web?
The World Wide Web, or just “the Web” for short, is a standardized system for accessing and navigating the Internet. It isn’t the only one (email and mobile apps, for instance, do not make use of the Web to connect you to the Internet), but it is by far the most common.
The Web is distinguished from other systems by its use of HTTP Hypertext Transfer protocol which in turn is just a system for standardizing the use of HTML Hypertext mark up language .Essentially, HTML is the language of the Web, and HTTP is the grammar rules for using it. In the same way that English is the language of business or French the language of love, HTML is the language of the Web.
Just as having a language in common allows us to communicate, understand one another, and share ideas or information, standardized HTML usage allows everyone accessing the Internet through the Web to discover, access, and communicate digitally. Importantly, accessing the Web requires a Web browser (like Internet Explorer, Chrome, Safari or Firefox) to make sense of HTML and allow Web pages to display properly. Meanwhile, you don’t even need a screen to connect to the Internet — smart speakers and other sundry connected devices don’t “speak” HTML, and so don’t use HTTP, open pages, or surf.
WHAT IS INTERNET KEY EXCHANGE PROTOCOL
Internet Key Exchange (IKE) is the standard used for remote host, network access, and virtual private network (VPN) access.
IKE enables two parties on the Internet to communicate securely. Specifically it is a key management protocol used to set up a security association (SA) using Internet Protocol Security (IPsec).
IKE uses X.509 certificates to authenticate, whether pre-shared or distributed, and a Diffie–Hellman key exchange to create a shared session secret through which cryptographic keys are derived.
In Phase 1 IKE establishes an authenticated connection between the host and user before generating the private key (mutual secret) that make Phase 2 or subsequent communications secure.
“Our VPN uses IKE so when you’re working from home, you can be sure that it’s you and the home office — and only those two parties — working over a secure connection.”
Internet Key Exchange (IKE) is a key management protocol standard used in conjunction with the Internet Protocol Security (IPSec) standard protocol. It provides security for virtual private networks’ (VPNs) negotiations and network access to random hosts. It can also be described as a method for exchanging keys for encryption and authentication over an unsecured medium, such as the Internet.
IKE is a hybrid protocol based on:
- ISAKMP (RFC2408): Internet Security Association and Key Management Protocols are used for negotiation and establishment of security associations. This protocol establishes a secure connection between two IPSec peers.
- Oakley (RFC2412): This protocol is used for key agreement or key exchange. Oakley defines the mechanism that is used for key exchange over an IKE session. The default algorithm for key exchange used by this protocol is the Diffie-Hellman algorithm.
- SKEME: This protocol is another version for key exchange.
IKE enhances IPsec by providing additional features along with flexibility. IPsec, however, can be configured without IKE.
IKE has many benefits. It eliminates the need to manually specify all the IPSec security parameters at both peers. It allows the user to specify a particular lifetime for the IPsec security association. Furthermore, encryption can be changed during IPsec sessions. Moreover, it permits certification authority. Finally, it allows dynamic authentication of peers.
Internet Key Exchange
Internet Key Exchange (IKE) is the protocol used to set up a secure, authenticated communications channel between two parties. IKE typically uses X.509 PKI certificates for authentication and the Diffie–Hellman key exchange protocol to set up a shared session secret.
IKE is part of the Internet Security Protocol (IPSec) which is responsible for negotiating security associations (SAs), which are a set of mutually agreed-upon keys and algorithms to be used by both parties trying to establish a VPN connection/tunnel.
- Pre-shared keys. A key value entered into each peer manually (out of band) and used to authenticate the peer.
- RSA signatures. Uses a digital certificate authenticated by an RSA signature.
- RSA encrypted nonces. Uses RSA encryption to encrypt a nonce value (a random number generated by the peer).
In phase 2, IKE negotiates the IPSec security associations and generates the required key material for IPSec.
The IKE works in two steps. The first step establishes an authenticated communication channel between the peers, by using algorithms like the Diffie-Hellman key exchange, which generates a shared key to further encrypt IKE communications. The communication channel formed as a result of the algorithm is a bi-directional channel. The authentication of the channel is achieved by using a shared key, signatures, or public key encryption.
There are two modes of operation for the first step: main mode, which is utilized to protect the identity of the peers, and aggressive mode, which is used when the security of the identity of the peers is not an important issue. During the second step, the peers use the secure communication channel to set up security negotiations on behalf of other services like IPSec. These negotiation procedures give rise to two unidirectional channels of which one is inbound and the other outbound. The mode of operation for the second step is the Quick mode.
IKE provides three different methods for peer authentication: authentication using a pre-shared secret, authentication using RSA encrypted nonces, and authentication using RSA signatures. IKE uses the HMAC functions to guarantee the integrity of an IKE session. When an IKE session lifetime expires, a new Diffie-Hellman exchange is performed and the IKE SA is re-established.