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The Sinking Ship of E-Mail Security

adamcaudill.com

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Re: The Sinking Ship of E-Mail Security

#41

Post by superuser2 »

freshhawk wrote: post #22
tptacek wrote: post #4

Mobile - Using PGP on a mobile device can be risky, as it requires storing the private key on devices that are likely to have known security issues. Many people recommend against it, as it puts the private key at too much risk. ARGH. The whole point of PGP keyrings --- the costliest part of the PGP UX --- is that you don't have to have a single key. If you're terrified of exposing your secret key on your mobile devic…

> which is frankly the most secure device you own Really? That's not how I treat my security at all. My phone seems to clearly be the least secure computer I own. Admittedly I run all linux on my non-phone computers, but I'm not totally sure I'd agree with you even if I ran Windows or OSX. Am I that wrong?

If it's an iPhone, then yes, it is far and away the most secure device you own. Everything is encrypted all the time through an HSM which will perform decryption only if given the device PIN. The key is never in memory and any attempt to extract it from the HSM will result in its self-destruction. It is impossible to recover data from the phone without the PIN. You can only erase the device and restore from a backup. While the device can be lost, the only threat is that a thief will erase and resell it. With iOS 7 and Find My iPhone turned on, even that is not possible. An attacker would not get your data in any case.

This is orders of magnitude safer than a full-disk-encrypted laptop because people hardly ever shut down their laptops, so keys remain in memory. There is also the possibility of cold-boot attacks, and of course the (retrospectively) insane design wherein any program you run can access all of your data.

iOS applications are always code-signed in a way that is tied to a real person or corporation, thoroughly sandboxed, and subject to review, making malware essentially non-existent. If discovered, it can be yanked at any time. What few remote exploits there have been were national news - and quickly resolved.

iMessage is end-to-end encrypted 100% of the time using a keybag - each device on your iCloud account has its own private key that never leaves the device. You get notified when a key is added to the keybag. This is really incredible, because without even knowing it, huge swaths of the population are using properly end-to-end encrypted messaging just by owning iPhones.

iOS is a tight ship and its attack surface is minuscule compared to that of a commodity computer.

Re: The Sinking Ship of E-Mail Security

#42

Post by raving-richard »

lifeisstillgood wrote: post #39
raving-richard wrote: post #31

Earlier quoted context omitted.

Anyway, even if a encrypted anonymous message arrives for me, just working out who it's from without any metadata seems complex web of double decryption It's simple. You can encrypt everything, including the metadata. Then, when it arrives in your box, you simply decrypt everything, and see who it's from. It doesn't have to be anonymous.

How do I know which key to use to decrypt it? If there is any identifier then that is an identifier for the sender - an irrevocable one that will slowly build up a metadata trail. Anonymity is hard if not impossible - it's why I don't think evoting can work and why this seems laudable but hard

Your software can try each key until one of them works. If none of them work, it can say "this message can't be opened with one of the keys available". Or even "this message requires key 1234 5678 to open, but it's not currently available". It's not something you need to care about. You don't need to have any information about the sender unencrypted. It's not at all necessary to deliver the message.

Re: The Sinking Ship of E-Mail Security

#43

Post by raving-richard »

leeoniya wrote: post #19
ams6110 wrote: post #17

I think of email like a postcard. It's addressed to me, but anyone can read it if they snoop in my mailbox. I don't expect it to be really secure, and I don't do anything that requires real security via email. Simple enough.

what arrives in your inbox is often out of your control. account confirmation and password reset emails, pictures/info others send you who are more satisfied that you with the level of privacy normal email provides, etc.

Yes, to extend the postcard metaphor, it's like the bank sending a bank card PIN on a postcard. Not secure at all.

Re: The Sinking Ship of E-Mail Security

#44

Post by lifeisstillgood »

raving-richard wrote: post #42
lifeisstillgood wrote: post #39

Earlier quoted context omitted.

How do I know which key to use to decrypt it? If there is any identifier then that is an identifier for the sender - an irrevocable one that will slowly build up a metadata trail. Anonymity is hard if not impossible - it's why I don't think evoting can work and why this seems laudable but hard

Your software can try each key until one of them works. If none of them work, it can say "this message can't be opened with one of the keys available". Or even "this message requires key 1234 5678 to open, but it's not currently available". It's not something you need to care about. You don't need to have any information about the sender unencrypted. It's not at all necessary to deliver the message.

Hmm - I get an average of 1000 messages a day, mostly spam, and I have - good grief - 4000 seperate email addresses in my inbox - and it just took 0.001 s to decode a txt file

So that's 4000 seconds to prove a message is spam

I'm not loving this idea

That can't be right ...

Re: The Sinking Ship of E-Mail Security

#45

Post by lifeisstillgood »

This has really got me thinking about an architecture I had not really considered before so forgive the obvious in this - it's partly aide memoire and partly a contribution to OP

- goals of the "new email" should presumably be to reduce the ability of state actors and major comms providers to collect sufficient metadata to conduct mass surveillance for tyranny or profit.

as such we can try either

- Vast citizen owned mesh networks (ie every smartphone is a ISP)

- Anonymity over traditional large ISPs / backbones

Anonymity is hard. We could encrypt entire message and then round robin decrypt each incoming message, this would cripple all metadata apart from the TO: field and mean any listener would need to own most entry points to catch the first uptake. It seems difficult - webs of trust, guessing the encryption key.

Add in other constraints - all messages in transit and at rest are encrypted - gmail becomes no more than S3 - and we see the end of free email, and weirdly a return to POP3 as the client must store all my mail.

If this does exist however, why restrict it to emails - every message format seems similar - MQ and Facebook can all go this way.

Mesh networks have even greater barriers to uptake ...

Re: The Sinking Ship of E-Mail Security

#46

Post by lifeisstillgood »

AnthonyMouse wrote: post #25
lifeisstillgood wrote: post #15

Ok, I'll bite. This is a good post - I am negative on your ability to pull this off, but it's a worthwhile discussion to have IMO * Totally anonymous (ie no metadata trail) communication seems impossible / impractical. If everywhere is the Tor then we massively increase traffic, (not to mention the trustworthiness of "everyone" is a lot lower per unit than everyone currently running a tor node) Anyway, even if a encr…

> Totally anonymous (ie no metadata trail) communication seems impossible / impractical. If everywhere is the Tor then we massively increase traffic That really isn't the problem. If onion routing works for anything it works for email. Text is low bandwidth. You make the email servers relay for each other so it scales: More email servers, more relays. And if you're willing to have your emails delayed by e.g. half an…

Duh!

I went off on one thinking how do I find which public key Of my 4000 contacts is the right one ... When no-one will encrypt a secret message with their own private key !

Sorry - total brain fart. Apologies to others down thread too.

Re: The Sinking Ship of E-Mail Security

#47

Post by lifeisstillgood »

superuser2 wrote: post #41
freshhawk wrote: post #22

Earlier quoted context omitted.

> which is frankly the most secure device you own Really? That's not how I treat my security at all. My phone seems to clearly be the least secure computer I own. Admittedly I run all linux on my non-phone computers, but I'm not totally sure I'd agree with you even if I ran Windows or OSX. Am I that wrong?

If it's an iPhone, then yes, it is far and away the most secure device you own. Everything is encrypted all the time through an HSM which will perform decryption only if given the device PIN. The key is never in memory and any attempt to extract it from the HSM will result in its self-destruction. It is impossible to recover data from the phone without the PIN. You can only erase the device and restore from a backup.…

Where do I read more about this - it sounds fantastic and yet I just assume "proprietary = lazily implemented and they can read my keys cos it's on their server"

Re: The Sinking Ship of E-Mail Security

#48

Post by rakoo »

lifeisstillgood wrote: post #44
raving-richard wrote: post #42

Earlier quoted context omitted.

Your software can try each key until one of them works. If none of them work, it can say "this message can't be opened with one of the keys available". Or even "this message requires key 1234 5678 to open, but it's not currently available". It's not something you need to care about. You don't need to have any information about the sender unencrypted. It's not at all necessary to deliver the message.

Hmm - I get an average of 1000 messages a day, mostly spam, and I have - good grief - 4000 seperate email addresses in my inbox - and it just took 0.001 s to decode a txt file So that's 4000 seconds to prove a message is spam I'm not loving this idea That can't be right ...

FYI, bitmessage (https://bitmessage.org/) is a working implementation of this "Everyone Gets Everything" model. Maybe have a look at how they do things ?

Re: The Sinking Ship of E-Mail Security

#50

Post by e12e »

lifeisstillgood wrote: post #47
superuser2 wrote: post #41

Earlier quoted context omitted.

If it's an iPhone, then yes, it is far and away the most secure device you own. Everything is encrypted all the time through an HSM which will perform decryption only if given the device PIN. The key is never in memory and any attempt to extract it from the HSM will result in its self-destruction. It is impossible to recover data from the phone without the PIN. You can only erase the device and restore from a backup.…

Where do I read more about this - it sounds fantastic and yet I just assume "proprietary = lazily implemented and they can read my keys cos it's on their server"

There was a talk at passwords^10 (2010) about security of pins/keys in iphone/android/windows phone (IIRC). Don't recall who the speaker was, and all the links to talks/programs etc have gone to bitrot (might be possible to find on archive.org, I've yet to try that).

If I remember correctly an encrypted iphone (4 I guess?) was the most secure, but with a bit of hackery one could use the device itself to bruteforce the pin (and thus access the key, and then the data). Not sure if that's actually been patched in later iterations of the iphone.

If you find this stuff interesting, consider going to passwords^14 (August 5th-6th, Las Vegas): https://passwordscon.org/

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