Symmetric key Encryption

Imagine Sara,She buys a bag full of padlocks that all use exactly the same key.Then she distributes the padlocks to her friends- open,but without a key. Now when her friend (suppose Jhon)wants to send something,he puts it in a box and then he locks the box with the padlock (padlock given by Sara ). Once jhon closes the padlock by simply pushing the lock handle (without any key) ,sara is the only one that can open it again,as she is having the only key... and her friends can send her messages but sara is the only one who can open them... Give this video a BIG THUMBS UP if it helped! Share this Video:https: //www.youtube.com/watch?v=0pKsFtPndYw Subscribe To Our Channel and Get More Great videos https://www.youtube.com/channel/UCB-r... Here is a Metaphore video that explains this concept in easy way..Hope you will like it!!!