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Posts Tagged ‘ssl’

How Can You Tell if an Email Was Transmitted Using TLS Encryption?

Tuesday, October 29th, 2019

Frequently, we are asked to verify if a sent or received email was encrypted using SMTP TLS during transmission. For example, banks, healthcare organizations under HIPAA, and other security-aware institutions require that emails be secured by TLS encryption.

Email should always be transmitted with this basic level of email encryption to ensure that the email message content cannot be eavesdropped upon. To see if a message was sent securely, looking at the raw headers of the email message in question is easy. However, it requires some knowledge and experience to understand the text. It is actually easier to tell if a recipient’s server supports TLS than to tell if a particular message was securely transmitted.

To analyze a message for transmission security, we will look at an example email message sent from Hotmail to LuxSci. We will see that Hotmail did not use TLS when sending this message. Hotmail is not a good provider to use when security or privacy are required.

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SSL versus TLS – What’s the difference?

Saturday, May 12th, 2018

SSL versus TLS

TLS (Transport Layer Security) and SSL (Secure Sockets Layer) are protocols that provide data encryption and authentication between applications and servers when that data is sent across an insecure network. The terms SSL and TLS are often used interchangeably or in conjunction with each other (TLS/SSL), but one is, in fact, the predecessor of the other. SSL 3.0 served as the basis for TLS 1.0, which, as a result, is sometimes referred to as SSL 3.1. With this said, is there a practical difference between the two?

SSL versus TLS: What is the differenc?

See also our Infographic which summarizes these differences.

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SMTP TLS: All About Secure Email Delivery over TLS

Monday, October 2nd, 2017

TLS stands for “Transport Layer Security” and is the successor of “SSL” (Secure Socket Layer). TLS is one of the standard ways that computers on the internet transmit information over an encrypted channel. In general, when one computer connects to another computer and uses TLS, the following happens:

  1. Computer A connects to Computer B (no security)
  2. Computer B says “Hello” (no security)
  3. Computer A says, “Let’s talk securely over TLS” (no security)
  4. Computer A and B agree on how to do this (secure)
  5. The rest of the conversation is encrypted (secure)

In particular:

  • The meat of the conversation is encrypted
  • Computer A can verify the identity of Computer B (by examining its SSL certificate, which is required for this dialog)
  • The conversation cannot be eavesdropped upon (without Computer A knowing)
  • A third party cannot modify the conversation
  • Third parties cannot inject other information into the conversation.

TLS and SSL are used for many different reasons on the internet and help make the internet a more secure place. One of the popular uses of TLS is SMTP for securely transmitting email messages between servers. See also:

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ARC and SMTP MTA-STS: The State of Domain-based Email Authentication – Part 3

Tuesday, September 19th, 2017

We’ll close (for now) our three part series on the state of domain-based authentication for emails by completing the story on technologies being deployed or defined to improve the security of the email ecosystem. In Part 1, we wrote about using Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) to authenticate the sending mail server. Part 2 described how Domain-based Message Authentication, Reporting and Conformance (DMARC) is used to provide clear guidelines for the treatment of mail that fail SPF and/or DKIM authentication.

In this post, we’ll touch on two topics that are mature works in progress in the IETF, the technical standardization organization that has brought us so much of the protocols that govern the internet. The first technology is Authenticated Received Chain (ARC), defined to handle the shortcomings of SPF and DKIM when used with mail forwarders or mailing lists. The second technology is about correcting the lack of security between Message Transfer Agents (MTA), and a solution to enforce strict transport layer security for SMTP message transfer between MTAs.

It’s worth reiterating again that all these technologies are building blocks, and only when used and deployed collectively by the entire ecosystem can we hope to create the barriers needed to thwart fake emails and mail surveillance by malicious actors.

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What’s the latest with HTTPS and SSL/TLS Certificates?

Wednesday, August 2nd, 2017

We’ve written quite a lot in past FYI Blog posts about SSL/TLS certificates, the critical building block to secure communication on the Internet. We described what such certificates were, their use in securing the communications channel between a client (browser) and a server, different types of certificates and the pros and cons of using each.

Given the changes in the Internet landscape over the past five years, we feel it is time to revisit these topics. The technical details described in the earlier posts remain unchanged. What has changed, though, are the traffic patterns for HTTPS-based communications, additional vulnerabilities arising as a consequence and ways to mitigate these. This post will provide a general overview of certain changes in the Internet landscape over the past few years, while subsequent blog posts will describe some of the topics identified here in greater detail.SSL TLS Certificates

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