What type of encryption is commonly used to secure email communications?

Public Key Infrastructure (PKI) encryption is the most widely used method for securing email communications. PKI utilizes a pair of cryptographic keys: a public key and a private key. The public key is shared with anyone who wants to send an encrypted message, while the private key is kept secret by the recipient. When someone encrypts an email using the recipient's public key, only the recipient can decrypt it using their private key, ensuring confidentiality.

This method not only enables encryption but also allows for digital signatures, which verify the sender's identity and ensure the message has not been altered in transit. The combination of these features makes PKI particularly suitable for ensuring secure and authenticated email communications.

In contrast, symmetric encryption relies on a single key for both encryption and decryption, which poses challenges for securely sharing the key over untrusted networks like email. Hashing algorithms serve different purposes such as ensuring data integrity and are not reversible, meaning they can’t be used to encrypt and decrypt messages. Steganographic techniques involve hiding information within other non-secret media and do not encrypt data in a traditional sense, making them less relevant for standard email security practices.