Asymmetric Encryption

What is Cryptography?

Cryptography is a discipline that protects the confidentiality of messages by using a key or a set of keys. We then talk about symmetric or asymmetric encryption.

Symmetric encryption

Here we use only 1 key. The way it works is trivial:

• The sender writes his message 
• The sender encrypts/cyphers his clear message using the same key
• The sender sends his encrypted message to the recipient
• The recipient decrypts the encrypted message with the key 
• The recipient reads the message

This is called symmetric cryptography: the same key is used to encrypt and decrypt the message

Asymmetric encryption

In asymmetric cryptography, we have two keys A and B. A and B are of course interdependent:

• Any message encrypted with key A can be decrypted with key B
• Any message encrypted with key B can be decrypted with key A 
• A message encrypted with key A cannot be decrypted with key A
• A message encrypted with key B cannot be decrypted with key B

Asymmetric cryptography offers 2 advantages over symmetric cryptography - In asymmetric cryptography, I broadcast key A (public key) to everyone and I keep key B (private key) and so :

• Anyone can send me an encrypted message with key A and I am the only one who can decipher it with the key B contrary to symmetrical cryptography where anyone could decrypt the message intended for me
• I am the only one who can encrypt a message (using key B) that is decryptable by key A, so I can prove my identity - I am the one who follows the origin of the key pair A/B.

Digital Assets Protection

It's the asymmetric encryption is used by our digital wallets and could be sumup in a very simplified way as follows:

• Everybody knows our public key, it's our wallet address, everybody can send us funds/crypto assets on it 
• I am the only one who knows the private key that is used to "decode" our address, so I am the only one who can decode/spend the funds/crypto assets on it