Email encryption

Email encryption is encryption of email messages to protect the content from being read by other entities than the intended recipients. Email encryption may also include authentication.

Email is prone to disclosure of information. Most emails are currently transmitted in the clear (not encrypted). By means of some available tools, persons other than the designated recipients can read the email contents. Email encryption has been used by journalists and regular users to protect privacy.

Email encryption 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.

for email encryption include:

The STARTTLS SMTP extension is a TLS (SSL) layer on top of the SMTP connection. While it protects traffic from being sniffed during transmission, it is technically not encryption of emails because the content of messages is revealed to, and can be altered by, intermediate email relays. In other words, the encryption takes place between individual SMTP relays, not between the sender and the recipient. When both relays support STARTTLS, it may be used regardless of whether the email's contents are encrypted using another protocol. STARTTLS is also an extension of and , as stated by RFC 2595.

Mandatory certificate verification is not viable for Internet mail delivery. As a result, most email that is delivered over TLS uses only opportunistic encryption. DANE is a proposed standard that makes an incremental transition to verified encryption for Internet mail delivery possible.

The Signed and Encrypted Email Over The Internet demonstration has shown that organizations can collaborate effectively using secure email. Previous barriers to adoption were overcome, including the use of a PKI bridge to provide a scalable public key infrastructure (PKI) and the use of network security guards checking encrypted content passing in and out of corporate network boundaries to avoid encryption being used to hide malware introduction and information leakage.

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