Let's Encrypt: How It Works • Hacker News Board

Re: Let's Encrypt: How It Works

#81

Post by josho » Fri, Nov 21, 2014, 11:27 PM UTC

ultramancool wrote: post #79

mike-cardwell wrote: post #77

Earlier quoted context omitted.

It will cost existing CAs a lot of business. We already had free certs from StartSSL, but they were for non-commercial purposes only. I imagine a lot of shared hosting companies who currently resell SSL certs to their own customers will be switching to this next year. I will certainly use them, and will only recommend them and nobody else. The only reason I'd ever look at one of the old CAs now, is for EV certs. But…

It's very, very hard for traditional CAs to compete with free, trusted in all major platforms and with dead simple set up. Hopefully this sort of scheme, combined with the added trust of Certificate Transparency, can kill off most traditional CAs. The only reason I would still buy 1 certificate is for wildcard support.

Wait. Where can I get free certs today? Or did you mean once this service goes live?

I've used StartSSL, but somehow messed up the process and can't issue a new cert unless I pay to revoke the current. Even then their free certs expire in a year.

The only other free cert I found was from Comodo, but it expires after 90 days.

So, I wouldn't exactly say the only reason to pay for a cert is for wildcard support.

Re: Let's Encrypt: How It Works

#82

Post by nnnnni » Fri, Nov 21, 2014, 11:50 PM UTC

The problem with their "howto" is that it completely ignores the fact that things like NAT and PAT need to be set up. Sure, the public IP's port 80 could be PAT-ed to the internal IP's port 80, but running "lets-encrypt example.com" can't magically PAT port 443 straight out of the package manager like that.

Still, this is a great idea...

Re: Let's Encrypt: How It Works

#83

Post by angry_octet » Fri, Nov 21, 2014, 11:58 PM UTC

Can someone clarify whether LE will check if there is already a signed SSL cert for the domain, and it contains the same information? For example, via the SSL Observatory?

Doing this would prevent a point in time vulnerability in DNS (temporary mitm showing a different IP for the domain) or direct mitm of the connection to the webserver. Otherwise the attacker could get a signed cert for https://peacenik.org, and then present that to activists that it mitms.

Re: Let's Encrypt: How It Works

#84

Post by bifurcation » Sat, Nov 22, 2014, 12:06 AM UTC

angry_octet wrote: post #83

Can someone clarify whether LE will check if there is already a signed SSL cert for the domain, and it contains the same information? For example, via the SSL Observatory? Doing this would prevent a point in time vulnerability in DNS (temporary mitm showing a different IP for the domain) or direct mitm of the connection to the webserver. Otherwise the attacker could get a signed cert for https://peacenik.org , and th…

Yes, we plan to apply a few mitigations of this type. Part of the idea of the "Proof of Possession of a Prior Key" challenge is so that if a web server requests a cert for a domain with an existing certificate, we can ask them to prove that they hold that certificate.

https://github.com/letsencrypt/acme-spec/blob/master/draft-b...

Re: Let's Encrypt: How It Works

#85

Post by stormbrew » Sat, Nov 22, 2014, 12:11 AM UTC

Here's a question I haven't seen anyone ask: What about email servers (SMTP/IMAP)? I need a good cert for that more than I do for https, personally. I could obviously have a web server up just to succeed at the challenge/response and get a certificate, but I actually just try to avoid running webservers at all these days, to be honest. I'm also not 100% that certificate would work.

Re: Let's Encrypt: How It Works

#86

Post by interested2 » Sat, Nov 22, 2014, 12:24 AM UTC

Will using a certificate from letsencrypt.org require any kind of agreement on the part of web site administrators or visitors to their web sites?

The CA's I've looked at have these agreements. I'd like to avoid binding myself or the visitors to my website to any legal requirements from a third party.

Re: Let's Encrypt: How It Works

#87

Post by icebraining » Sat, Nov 22, 2014, 12:33 AM UTC

sp332 wrote: post #23

cmwright wrote: post #8

Earlier quoted context omitted.

The SNI stuff ( http://en.wikipedia.org/wiki/Server_Name_Indication ) helps with this if you can do without XP support.

It's not really XP that's the problem, but IE6. Firefox and Chrome support SNI even if you run them on XP.

All IE versions on XP, alas.

Re: Let's Encrypt: How It Works

#88

Post by yuriks » Sat, Nov 22, 2014, 1:16 AM UTC

grey-area wrote: post #65

Great project to smooth out the really painful process at present for acquiring certs. How about an FAQ page or a few clarifications? Things I wanted to know which were not immediately apparent: Will it be broadly accepted from day one? Yes, apparently, though see the identrust issue below. Will it generate a keypair but keep the private key on your server? Yes. Will it work without having to babysit an interactive p…

https://www.identrustssl.com/ authenticates fine for me in both Firefox and Chrome, and the certificate issuers for both that site and https://letsencrypt.org/ is in fact the same. I did notice that the IdentTrustSSL certificate has been issued yesterday, so this might be an issue of wrong clocks on your end.

Re: Let's Encrypt: How It Works

#89

Post by iancarroll » Sat, Nov 22, 2014, 1:16 AM UTC

Supermighty wrote: post #26

aeden wrote: post #16

Earlier quoted context omitted.

The impact depends largely on their ability to get their root certificate into all of the browsers. It'll be interesting to see what happens with older versions of browsers as well, since if they start with a brand new root certificate then I'm not sure what happens with the older browsers. If they can get their certificate into all of the browsers then it's possible they could achieve broad adoption for domain-verif…

> since if they start with a brand new root certificate then I'm not sure what happens with the older browsers. IdenTrust will cross-sign Let's Encrypt root cert. I imagine they will keep it cross-signed, for backwards compatibility, once LE has their root cert in all the browsers.

You can't exactly undo cross signing without creating a new root CA - at some point they'll probably stop sending their root CA with the handshake (which is required when cross signing).

Re: Let's Encrypt: How It Works

#90

Post by yuriks » Sat, Nov 22, 2014, 1:20 AM UTC

stormbrew wrote: post #85

Here's a question I haven't seen anyone ask: What about email servers (SMTP/IMAP)? I need a good cert for that more than I do for https, personally. I could obviously have a web server up just to succeed at the challenge/response and get a certificate, but I actually just try to avoid running webservers at all these days, to be honest. I'm also not 100% that certificate would work.

The technical overview mentions that there can be various different kinds of challenges, so presumably you could use a DNS based one or even an email based one if it's implemented.