## Key terms

**Plaintext**: original data before encryption

**Cyphertext**: data after applying encryption algorithms

**Key**: a string that is used to encrypt or decrypt data

**Public key**: the key of the asymmetric key pair that is shared with the public

**Private key**: the key of the asymmetric key pair that is kept by the receiver

## Symmetric cryptography

Symmetric cryptography uses the same key to encrypt and decrypt data, hence the name ‘symmetric’, meaning the same on both sides.

Note left of Sender: Encrypts message with key

Sender->Receiver: Sends key

Sender->Receiver: Sends encrypted message

Note right of Receiver: Decrypts message with key

## Asymmetric cryptography

Asymmetric cryptography generates a public-private key pair where the public key is used for senders to encrypt messages and the private key is used for the receivers to decrypt messages, hence the name ‘asymmetric’, meaning different on the two sides.

Note right of Receiver: Generates Public-Private Key Pair

Receiver->Sender: Sends Public Key

Note left of Sender: Encrypts message with Public Key

Sender->Receiver: Sends encrypted message

Note right of Receiver: Decrypts message with Private Key