Symmetric and asymmetric encryption

There are two main kinds of ciphers (and, consequentially, of encryption): symmetric and asymmetric, and the difference lies in the kind of keys that are used.

Symmetric encryption is probably the most well-known of the two, and the one that consumers are more likely to be familiar with as well. With symmetric encryption, you encrypt data using a key, and then use the very same key to decrypt it again. In many cases, the key can be derived from a password or passphrase, as we'll see at the end of this chapter.

Conceptually, algorithms such as AES (one of the most popular and widely used symmetric ciphers) and ChaCha20-Poly1305 work this way.

If you wanted to share the encrypted message with another person, you'd need to provide the other party with both the ciphertext (the encrypted data) and the key. Like many people, even consumers have experienced, in this case, the challenge of sharing the encryption key securely. Having the...