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How e-mail works and its security

An email, or e-mail, is a message sent by a sender to one or more recipients. The transfer of these messages is handled using SMTP (Simple Mail Transfer Protocol) which, like HTTP, is also based on the Internet Protocol. Protocols are the ways to communicate between several computer systems speaking the same language.

How an email travels

After you compose a message in a Web site or in an e-mail program, it is transferred to an outgoing server by using SMTP. It is then transferred over networks or from one message server to another, again using SMTP, until it reaches its final destination server.

There are two important servers, POP3 and SMTP. These are protocols for managing emails on the Internet. The difference between them is that with the SMTP protocol it takes care of sending  emails (what you send), while POP3 is responsible for  receiving  emails (the ones you receive).

Who decides where the e-mail is going

Mail servers find out where to send emails by querying domain name system (DNS) information. This system also includes information about which servers are responsible for handling emails for each domain.

The domain is extracted from the end of the recipient after the @ sign. Once the message reaches the server that handles all emails for the recipient, it will remain there until the recipient deletes it. It is stored that way on that server.

There are electronic messaging applications that will automatically download that message to the PC since they are messages that are downloaded to the user’s computer or smartphone.

E-mail security

When you send an email it can be intercepted by third parties as they are sent over the Internet from one server to another server. There are two ways to prevent this from happening:

  • Ensure communication between the mail server.
  • Or encrypt the content of messages.

Securing communication between electronic messaging servers occurs in the same way that HTTPS secures communication over HTTP. One weakness in the case of email is that your computer does not communicate directly with the final destination mail server. As a result if a single intermediary server does not use encryption to send your message, it could still be intercepted by a third party.

Mail encryption

Encryption is the process of encoding messages or information in such a way that only authorized parties can read it. Using complex algorithms, the message is transformed into an unreadable character string without the uniquely generated key. This unique key allows the message to be transformed back into its original format.

Several mail providers use encryption to encrypt and decrypt the messages it sends and receives. All messages that you send to other users are encrypted in this way.

A famous and encryption method available for free for PGP electronic messaging(Pretty Good Privacy),also available as OpenPGP and GPG. OpenPGP is the most widely used email encryption standard. It is defined by the Internet Engineering Task Force (IETF) OpenPGP Working Group as a standard proposed in RFC 4880.

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