How does encryption work in secure email communication?

Encryption in secure email communication works by converting plain text into unreadable cipher text using cryptographic keys.

In more detail, secure email communication relies on a process known as encryption to protect the content of emails from being read by unauthorised individuals. This process involves transforming the original message, known as plain text, into an unreadable format, known as cipher text. The transformation is done using a specific algorithm and a key, which is a string of random bits created specifically for the purpose of encryption.

There are two main types of encryption used in secure email communication: symmetric and asymmetric encryption. Symmetric encryption uses the same key for both encryption and decryption. This means that the sender and the receiver must both have the same key, which can be a security risk if the key is intercepted during transmission.

Asymmetric encryption, on the other hand, uses two different keys: a public key for encryption and a private key for decryption. The public key is available to anyone, but the private key is kept secret by the owner. When someone wants to send a secure email, they encrypt it using the recipient's public key. Only the recipient, who has the corresponding private key, can then decrypt and read the email. This method is more secure because even if the public key is intercepted, the email cannot be decrypted without the private key.

One common method of secure email communication is Pretty Good Privacy (PGP). PGP combines symmetric and asymmetric encryption for increased security. The message is encrypted using a one-time symmetric key, which is then encrypted using the recipient's public key. The recipient can decrypt the symmetric key with their private key and then use the symmetric key to decrypt the message.

Another method is Secure/Multipurpose Internet Mail Extensions (S/MIME), which is built into most modern email software. S/MIME also uses a combination of symmetric and asymmetric encryption, but it also includes a system of trusted certificates for verifying the identity of the sender.

In conclusion, encryption plays a crucial role in secure email communication by ensuring that only the intended recipient can read the email.