What is E-mail encryption?

E-mail encryption is the process of encoding e-mail messages to protect the content from being read by un-authorized parties and can be read only by intended recipients.  E-mail authentication is also a part of e-mail encryption. E-mail has risks of disclosing information. Most emails are currently transmitted in the clear. E-mail encryption has been used by corporates and regular users to protect privacy. It can rely on public-key cryptography, in which users can each publish a public key that others can use to encrypt messages to them, while keeping secret a private key they can use to decrypt such messages or to digitally encrypt and sign messages they send. There are alternative encryption systems that use an external code generated via a key, the key may be sent in a follow up email or via a SMS text. The recipient then uses the same key as the sender to look-up the one-time cypher.