Digital Signatures in Blockchain

In the next video, Shebin talks about Symmetric signatures. You will learn how "keys" are used to sign the documents digitally. 

So, in symmetric digital signatures, one single key is used to encrypt the messages. The sender encrypts the message with that key and sends it to the receiver. Once the receiver recerives it, they need the same key to decrypt or unlock that message. So, the sender also shares the key  he/she encrypted the message with so that the receiver can use it to decrypt the message.  In the next video Shebin talks about Asymmetric Digital Signatures and tells how they are used to overcome the shortcomings of Symmetric signatures.

In Asymmetric Digital Signatures, a pair of public and private key is used. A message encrypted with a public key can only be decrypted with the corresponding private key of the public-private key pair and vice versa. The public key of each participant is shared across the network and private key is held secret only with the individual.