Cryptography for Noobs
Cryptography is the science of secret writing with the intention of keeping the data secret. Cryptography is classified into symmetric cryptography, asymmetric cryptography, and hashing.
We shall discuss Asymmetric and Symmetric keys here.
Asymmetric Cryptography (Public)
It is popularly known as Public-key Cryptography or Public-Key Encryption. It is a method of encrypting data with two different keys and making one of the keys, the public key, available for anyone to use. The other key is known as the private key. Data encrypted with the public key can only be decrypted with the private key, and data encrypted with the private key can only be decrypted with the public key.
Symmetric Cryptography (Private)
Symmetric encryption is also called secret key encryption, and it uses just one key, called a shared secret, for both encrypting and decrypting. This is a simple, easy-to-use method of encryption, but there is one problem with it: The key must be shared between the sender and the recipient of the data, so a secure method of key exchange must be devised. Otherwise, if a third party intercepts the key during the exchange, an unauthorized person can easily decrypt the data.
To give you some more perspective, let us study about differences between the two;
- Private Key is faster than Public Key, as the same key (secret key) and algorithm is used to encrypt and decrypt the message.
- Private key is Symmetrical because there is only one key that is called secret key whereas Public key is Asymmetrical because there are two types of key: private and public key.
- In Private key cryptography, sender and receiver need to share the same key, which is not the case with Public Key Cryptography.
- In Private key cryptography, the key is private. Also the same key (secret key) and algorithm is used to encrypt and decrypt the message.
- In public key cryptography, two keys are used, one key is used for encryption and while the other is used for decryption