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Let us continue with the cryptography section in this video.

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I am going to cover similar to key cryptography or asymmetric encryption, and I will give you a real

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live example with Alice and Bob Symmetric, key cryptography or asymmetric encryption, the type of

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encryption scheme in which the same key is used both to encrypt and decrypt the messages.

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Such a method of encoding information has been largely used in the past decades to facilitate secret

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communication between governments and militaries.

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Nowadays, similar algorithms are widely applied in various types of computer systems.

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Glennon's data security.

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Now I would like to explain you symmetric encryption with a real life example of Alice and Bob.

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Consider at least one to send a private image to Bob, and the only easy way to communicate is via postal

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M..

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Unfortunately, Alice is pretty much sure that the postman is reading the mail she sends.

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This makes Alice said.

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So she decides to find a way to send a message to Bob without anyone else being able to read them.

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Alice decides to put the message inside a lock box, then mail the box to Bob.

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She buys a lock box and two identical keys to open it.

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But then she realizes she can send the key to open the box to Bob via mail, as the mailman might open

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the package and take a copy of the key.

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And still, Alice arranges to meet Bob at nearby, but to give him one of the keys.

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It's inconvenient, but she only has to do it once.

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After meeting Bob, Alice gets home.

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He uses her key local message into the lock box.

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Then she sends the lock box to Bob.

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The mailman could look at the outset or even throw the box away.

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So Bob doesn't read the message, but there is no way he can read the message as he has no way of opening

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the lock box.

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Now, Bob can use his identical key to unlock the lock box and read the message.

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This works well.

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And now that Alice and Bob have identical keys, Bob can use the same method to security.

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Blair meeting at the bar to exchange keys.

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It's inconvenient, though.

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It gets more inconvenient when Alice and Bob on opposite sides of an ocean.

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So far, this asymmetric encryption is used, which we will see in upcoming videos.

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In the next lecture, we will see at once symmetric encryption.