 Now as you had seen in our previous lectures that the information that goes around is in clear text I mean if anybody captures that information that is available to be read in the way it is and for example if you are Sending your passwords. So if the passwords are captured in clear text anybody who captures it could know your password. So It is prone to something called eavesdropping, which is basically that somebody is trying to listen over the conversation So in networks what they have done is they have used something called the encryption Encryption is basically changing the human readable form using some mathematical function a very basic example or the first time an encryption was used was some Something at the time of the Roman emperors and they used to call it the Caesar Cypher So how it would happen is so instead of the alphabet a they would use C which is the third Third alphabet. So the entire message would be coded in such a way where Alphabet they have to use suppose they had to write ABC. So they will write C D e So this was one of the earlier ways of using an encryption. So later it started evolving by Changing the delta which is here. It was three So they would use say four or for each communication They would change just the number of shifts that they have to do and they would just communicate the number so that became the secret that they were sharing instead of the entire key and Even this was prone to leakages like somebody could leak out what the key was and Again the encryption could be broken. So in the current scenarios what we see is a very much more complicated Forms of encryption. So we have two types of encryptions one is called the symmetric and the other or other is called asymmetric Symmetric is the one we saw like in Caesar Cypher symmetric means your encryption or coding uses the same key and Decryption which is decoding uses the same key. So it's the symmetric use of keys Whereas in asymmetric encryption. What we see is we use a different key for Coding it and different key for decoding it as you said encryption and decryption So that was the example that we saw in Aditi and Balraj's case Along with encryption public private key pair or what we just saw the two key pairs as then as you were talking about the public part And the private part. So this can also be used to authenticate. We'll be looking at these three terms called Confidentiality integrity and availability. These are the three key terms of what security is about and There you will see how this encryption and a few other Techniques can be used to achieve those and along with this we could also use a hybrid method Which is like we can use asymmetric and symmetric So that could be in a way that if you were to send the symmetric key earlier that we were sending Which was prone to ease dropping So what we could do is send the key using the asymmetric encryption and then the Majority of the the majority of the communication could happen using a symmetric and why to do so because symmetric encryption is something which is Not that process in in intensive as compared to asymmetric. So you could just send the key by Asymmetric and we could have the communication in a symmetric encryption