What are public and private key cryptography?
There are two basic concepts in cryptography: encryption and decryption. Encryption is the transformation of the original message into an unreadable, i.e., encrypted one. Decryption is the conversion of an encrypted message back to its original form. An algorithm and key are used for both encryption and decryption, and there are two methods of encryption and decryption: symmetric and asymmetric encryption. Symmetric encryption, also called private key encryption, has been known to humanity for a very long time. On the other hand, asymmetric encryption, also called public key encryption, appeared only in the 1970s and became really widespread as the Internet developed.
What is private key encryption?
Private key encryption is a very popular, simple and effective encryption system. It allows both encryption and decryption to be performed using the same key. Since anyone who has the key can decrypt information encrypted in this way, this key must be kept secret and accessible only to the sender and the recipient of the information. This is why its called a private key, and the encryption system itself is called private key encryption.
What is public key encryption?
This encryption system is much more complex, using the private key only to decrypt the message. To encrypt the same message, a separate public key derived from the public key is used. If a person knows the private key, they can calculate the public key. However, knowing only the public key isnt enough to calculate the private key. Thats why the public key doesnt need to be kept secret since knowing it doesnt allow encrypted information to be decrypted.
How does public and private key encryption work?
In private key cryptography, the sender encrypts the message using the private key and sends it to the recipient. For the recipient to decrypt the message, theyll need the sender to provide the same private key through a wellsecured channel, thus reducing the security of such cryptographic systems.
In public key cryptography, the message sender encrypts the message with the public key and sends it to a recipient. The message recipient receives it and decrypts it with the private key that only he or she has. Since only the recipient needs a private key in this encryption system, it doesnt have to be sent, thus increasing its security. In public key cryptography, only the recipient — not even the sender — can decrypt the message.
The advantages and disadvantages of public key cryptography
Lets see the advantages and disadvantages of these encryption systems by comparing them.
Comparison of private and public key cryptography
Private key cryptography 
Public key cryptography 

Encryptiondecryption speed 
Faster 
Slower 
Required computing power 
Less 
More 
Need to send a private key via a secure channel 
Yes 
No 
Key length 
Shorter 
Longer 
Parties who need to know the private key 
Recipients and senders 
Recipients only 
Complexity of key management in a large network 
High 
Low 
Able to be used to generate an electronic digital signature 
No 
Yes 
In this comparison, we see that although private key encryption is much simpler and faster, its not a suitable option for blockchain networks.