PROTOCOLS(Contd)+ IF-Elif-else-2

Good Morning boys

In today's session also, we will divide the class in two parts.
In the first half , we will learn about few PROTOCOLS used by computers and in the second half, we will further look at the detailed working of IF-elif-else Decision Construct, as requested by few students.
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The Google Meeting ID

Meeting ID

meet.google.com/aqq-kdst-azf

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By the end of today's session, you will be able to

• Understand the need for protocols while communicating on the internet.
• Understand the method of communication using TCP/IP, HTTP, HTTPS,SSL & TSL Protocol.
• Understand the detailed working of the protocols.

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PROTOCOLS

1. Transmission Control Protocol / Internet Protocol (TCP/IP)
• It is a collection of communication protocols used to connect network devices on the internet.
• Can also be used to communicate in a private network.
• Provides end-to-end communication.
• Specifies how to exchange data over the internet.
• breaks the original data into small and manageable packets which are transferred to the destination
• makes the network reliable by recovering automatically in case of a failed device

       TCP-

• It defines the creation of communication channel across the network
• Helps to :
• divide the message into smaller packets
• then to reunite the packet at the destination

      IP-

• Helps the packet to reach its destination by putting the IP address of the destination on the packets.
• Each gateway on the network checks this IP.
• Routes the packets to its destination.

2.    HTTP- 

• Stands for Hyper Text Transfer Protocol.
• Communication protocol used to connect to :
• web server on the internet or
• on a local network (intranet)
• Primary function is 
• to establish a connection with the server
• send HTML pages back to the users browser
• Whenever we download files from the server to the browser we actually use HTTP.
• Addresses of websites begin with the prefix http://
• Web browser normally add http:// as a default to the web URLs or addresses.
• It is a "Stateless Connection".
• connection between client and server is maintained 
• It does so only for single request 

                                                              OR

• HTTP client establishes a TCP connection with the server
• sends it a request
• the server sends back its response
• closes the connection
• and then the connection is closed
• Example : When we type www.stcolumbas.edu.in, the browser automatically adds http://
• 
  

3. ENCRYPTION:

• makes sure that any data transferred between users and sites, or between two system remain impossible to read by an unauthorized person
• The two systems can be
• server
• client
• used for transmission of sensitive information that needs to be protected:
• credit card numbers
• other financial information
• other personal data such as
• names
• addresses

4. SSL and TLS:

• SSL stands for Secure Socket Layer
• TLS stands for Transport Layer Security
• Both are standard technologies used for 
• keeping an internet connection secure
• preserving any sensitive data being sent between two systems
• Both technologies use encryption to secure data.

5. HTTPS:

• Stands for Hyper text Transfer Protocol Secure
• encrypted version of HTTP
• is used to access secure web server
• https:// is the prefix used for HTTPS rather than http://
• Usually , security protocol TLS manages the request- response session
• TLS creates an encrypted connection between the user's browser and a web server- so that all transmissions are encrypted to and from the web server.
• TLS also uses digital certificate to authenticate the server.
• SSL was the predecessor of TSL
•   All websites that indulge in commercial activities use HTTPS:// protocol. 

6. HTTPS Everywhere

• Is a browser extension that retrieves web pages using the secure(encypted) HTTPS protocol rather than the non-secure HTTP.
• It sets the connection to HTTPS for all the pages in a website that support it.

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PYTHON PROGRAMING

#PROGRAM TO FIND LARGEST OF TWO  NUMBERS

num1=int(input("Enter the first number-"))

num2=int(input("Enter the Second number-"))

if(num1>num2):

    print(num1," is greater than ",num2)

else:

    print(num2," is greater than "num1)

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#PROGRAM TO FIND LARGEST OF TWO  NUMBERS

num1=int(input("Enter the first number-"))

num2=int(input("Enter the Second number-"))

if(num1>num2):

    print(num1," is greater than ",num2)

elif(num2>num1):

    print(num2," is greater than "num1)

else:

    print(num1," = ",num2)
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Home WORK

Write a program to accept 3 numbers from the user and find the largest of the three