The Technology Behind Envelope-Content Splitting (ECS)
Traditional Mail Technology
In traditional e-mail messaging systems, which haven't changed much since they were conceived in the 1970s, the mail headers (To:, From:, Subject, etc., collectively referred to as the envelope) are attached to the mail content, which includes the body of the e-mail message and any attachments.
Then the entire package is sent to the mail network for routing to the recipients. As a result, your message content is accessible by any intermediaries in the network, such as mail servers, thus putting your privacy at risk. Furthermore, once the mail content is received by your recipients, you've lost control of your content and mail address spoofing,
in which senders masquerade as others, can occur, resulting in identity theft and often enabling malware to be installed on unsuspecting users' systems.
Traditional mail technology makes poor use of mail resources. For example, when sending mail to multiple recipients, several copies of the same content are sent through the network, which may, when using large distribution lists and attachments, cause unnecessary network bottlenecks and waste disk space in users' mailboxes.
ECS Mail Technology
ECS technology (formerly, dynamic content), on the other hand, solves the above problems by splitting off the mail envelope from the content. Only the envelope, plus a small default message, is sent through the mail network, while the message content, including any attachments, is sent via secure, proprietary channels to a content server that resides outside of the mail network. Thus,
your message content is unavailable to mail intermediaries. Moreover, since only the envelope, rather than actual message content, is sent to your recipients,
not only is much less space taken up in their mailboxes when using ECS, but you, the sender, retain the ability to change your message content, including attachments, at any time (subject to content server settings).
The following takes place when sending, reading or editing an ECS mail message:
- When mail is composed, the mail client sends the message content and any attachments to a content server for storage and management
- The content server stores the content, including attachments, in separate files sole under its control and returns to the mail client pointers to the content
- The mail client stores the content pointer(s) in the mail header, places a default message in the message body and sends the message through the mail system
- When the recipient receives the message, the mail client fetches the first content pointer from the header and uses it to send a request to the content server to retrieve the message body content
- The content server fetches the content and returns it to the mail client for display
- If the recipient opens an attachment, the attachment content is retrieved the same way as above, using the respective content pointers
- In order to edit a mail message, the sender selects the message to be edited and makes the desired changes
- The mail client sends an update request, along with the corresponding content pointer contained in the original message and the edited content, to the content server
- The content server replaces the content of the original message with the edited content
- Attachment editing is done the same way as above
All commands for sending, reading or editing ECS content sent by the mail client to the content server include the user's e-mail address and a content server password. Thus, spoofing an ECS content message is only possible if the spoofer knows the password of the user he is trying to imitate.
Secure communications and storage
All data transferred between the mail client and the content server is encrypted, using the same technology to secure credit card transactions in transit. Thus, there is very little chance that your mail would be intercepted and read by unauthorized users when it's sent via ECS. Also, to ensure the security and privacy of your mail content on the ChiaraMail content server, you may choose to encrypt your mail prior to sending, using 256-bit AES (symmetric key) encryption. AES encryption is done easily at the time you send your mail and does not require any complicated key exchanges.