What is a key pair?
Key pairs are made up of a public key and a private key. A public key is used to encrypt data. A private key is the secret part of the key pair and should never be divulged to anyone. A private key is used to decrypt data. A public key is not secret and can be freely shared with anyone. Key pairs use a key algorithm to transform information from readable text into encrypted data.

What is a key size?
Your digital identity’s secret has a size. The bigger it is, the harder it is for others to discover and misuse. However, a bigger key size also makes all operations with your identity’s key slower. Key size is measured in “bits.” A good size of an identity you mean to use for a few years is 4096 bits.