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STARTTLS is of little help. It's client to server encryption. If say, alice@ispa.com emails bob@ispb.ru, then the transit between Alice's computer and IspA, Isp

STARTTLS is of little help. It's client to server encryption. If say, alice@ispa.com emails bob@ispb.ru, then the transit between Alice's computer and IspA, IspA and IspB, and IspB and Bob is protected. But only during transit. Both IspA and IspB get a completely cleartext email in their servers, where there well could be monitoring equipment or software installed. If you're concerned about a family member watching the traffic going through your router, this fixes your problem. But if you're concerned about governments, it absolutely does not, because they can easily convince an ISP to install interception infrastructure inside their datacenter, where the mail is in clear text. PGP on the other hand is end-to-end, Alice to Bob, and the data doesn't exist as cleartext anywhere else.

jcranmer 5y ago
There are two things you're missing here. The first, and more minor one, is that effective deployment of keys for encryption/signing tends to require cooperation of the email provider anyways, giving them the ability to report trusted keys for your identity that they can use to MITM you. Indeed, a few of the suggestions for key distribution contained in threads on this post have exactly this flaw (I leave it an exercise to the reader to find which ones). More importantly, even PGP doesn't fully protect information: the headers are still sent in full plaintext. This means that your email provider still knows whom you talked to, when you did so, and the subject of your message. I suspect that most of the government's interest in your personal email isn't in the contents of the email, but precisely this metadata that PGP makes no effort to hide whatsoever. If you're a dissident in Venezuela who's worried about the government finding out you're talking to foreign reporters... well, PGP won't help you. This ends up being the conundrum of "secure" email: it's sufficient for the job (assuming that the UX is more well-thought out than it often is) only if you want to hide what you're saying but not whom you're saying it to. And that is not sufficient for what most people who want secure messaging desire.
- lifeisstillgood 5y ago
  Do other message protocols / apps solve this meta-data problem as well? As I understand it a mobile to mobile protocol will need to send a message between app on phone on cell tower, through ISP, all of which presumably are open to similar government persuasion. I know its not as egregious as email headers, and email is distributed but the basics seem similar.
  - tptacek 5y ago
    Yes, this is a problem Signal was designed to address. It's interesting to note that many other secure messengers don't handle this much better than email does; they store serverside contact lists, so when you sign into your account your buddy list is immediately populated. Which means they're storing a graph of who talks to who, in a centralized location.
- zelphirkalt 5y ago
  Does the mail provider not have to know these things, in order to send the e-mail to its intended destination?
  - jcranmer 5y ago
    I suspect that, for email, avoiding the metadata loophole is basically impossible.
throw0101a 5y ago
> But if you're concerned about governments, it absolutely does not It helps against governments tapping glass and doing wholesale surveillance. Defeating that is a useful service.

jcranmer 5y ago

There are two things you're missing here. The first, and more minor one, is that effective deployment of keys for encryption/signing tends to require cooperation of the email provider anyways, giving them the ability to report trusted keys for your identity that they can use to MITM you. Indeed, a few of the suggestions for key distribution contained in threads on this post have exactly this flaw (I leave it an exercise to the reader to find which ones). More importantly, even PGP doesn't fully protect information: the headers are still sent in full plaintext. This means that your email provider still knows whom you talked to, when you did so, and the subject of your message. I suspect that most of the government's interest in your personal email isn't in the contents of the email, but precisely this metadata that PGP makes no effort to hide whatsoever. If you're a dissident in Venezuela who's worried about the government finding out you're talking to foreign reporters... well, PGP won't help you. This ends up being the conundrum of "secure" email: it's sufficient for the job (assuming that the UX is more well-thought out than it often is) only if you want to hide what you're saying but not whom you're saying it to. And that is not sufficient for what most people who want secure messaging desire.

lifeisstillgood 5y ago
Do other message protocols / apps solve this meta-data problem as well? As I understand it a mobile to mobile protocol will need to send a message between app on phone on cell tower, through ISP, all of which presumably are open to similar government persuasion. I know its not as egregious as email headers, and email is distributed but the basics seem similar.
- tptacek 5y ago
  Yes, this is a problem Signal was designed to address. It's interesting to note that many other secure messengers don't handle this much better than email does; they store serverside contact lists, so when you sign into your account your buddy list is immediately populated. Which means they're storing a graph of who talks to who, in a centralized location.
zelphirkalt 5y ago
Does the mail provider not have to know these things, in order to send the e-mail to its intended destination?
- jcranmer 5y ago
  I suspect that, for email, avoiding the metadata loophole is basically impossible.

throw0101a 5y ago

> But if you're concerned about governments, it absolutely does not It helps against governments tapping glass and doing wholesale surveillance. Defeating that is a useful service.