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**Carlisia Thompson:** No. If you're getting a TLS from a particular CA - Let's Encrypt is one, but there are others... There are different places to get a certificate from. |
**Matt Holt:** When you get a certificate, cryptographically it doesn't matter what kind of certificate you get, as long as the certificate authority is trusted by your users. There are certain certificate authorities that I would favor more than others or not favor less than others, based on their business practices..... |
**Erik St. Martin:** So let's actually talk about that for a second. I mean anytime we talk security, that's always gonna come up, this trust. That's ultimately what it comes down to, is who do you trust? So let's talk about some of the things that can go wrong if you chose a certificate authority that may not be trust... |
**Matt Holt:** Yeah. I'll use an example, and this is just a recent news item. I'm not endorsing or I'm not suggesting one way or another, but recently Symantec issued certificates that were SHA1 signed. Now, SHA1 is officially deprecated for TLS certificates, because of weaknesses with collisions that have been recent... |
And then when they officially asked after that for the issuance of seven SHA1 signed certificates as a special case, the request contained unusual strings in one of the fields in the certificate. And that was concerning, because at least the security researchers say that a collision attack could likely include such unu... |
Anyway, so here you have the certificate authority whose practices are disputed. Now, in the end they issued the certificates, but they took out those questionable strings. I mean, you be the judge of who your certificate authority is, but cryptographically remember that no certificate is better than another. You can m... |
**Carlisia Thompson:** \[23:50\] Exactly, but how... Let's say I'm a developer, and for some reason I don't wanna use Let's Encrypt. Let's say I don't wanna pay and they renew every three months, and I don't wanna go through the renewal process every three months. |
**Matt Holt:** Why not? |
**Carlisia Thompson:** Let's say I have reasons, let's say I at least consider other entities. How do I go about trusting an entity? What are the rules of thumb that I need to think about? Are there things that I can look at? Like, this company does this, or … |
**Matt Holt:** You know, the way I do it is I just follow the TLS news, TLS-related news. Certificate transparency logs is like a raw source of who is issuing what certificates. Whether a certificate authority even submits to certificate transparency is probably a good indicator. I just Google Security research. They d... |
**Carlisia Thompson:** And how about the ACME protocol? I was thinking... It sounds like a big deal. I also noticed that not every company that issues certificates implements this protocol. What is it and does that even matter? |
**Matt Holt:** Okay, yeah. The ACME protocol - this is a really big deal, because it automates away the job of certificate authorities. Now, we still need certificate authorities, but the manual process of interacting with them goes away. The ACME protocol stands for Automated Certificate Management Environment. This w... |
J. Alex Halderman was one of the researchers there. The project, as it came to fruition, it came through the Internet Security Research Group and Mozilla funding and their brand now is Let's Encrypt; it is really making the ACME protocol shine. And so what this means is that you have the certificate authority Let's Enc... |
So this protocol allows them to verify your claim that you own a domain name and they can issue you certificates. And the protocol has been vetted pretty thoroughly for flaws and bugs. Is it perfect? No. They found a couple, but they fixed it. They're still in beta. But this protocol basically automates in two seconds ... |
**Brian Ketelsen:** At least, yeah. |
**Matt Holt:** So the certificate authority is actually irrelevant here. The fact that Let's Encrypt is the automated certificate authority is just a matter of circumstance right now. But any certificate authority can implement ACME. It's an open protocol, it's published. I see the link here in Slack for the spec. So I... |
**Carlisia Thompson:** That's also important because, as I understand it, you can be a CA, but the rules of how you validate a certificate's authority, they are very loose, correct? |
**Matt Holt:** Certificate authorities have pretty rigid guidelines. I don't know a whole lot of details, because I don't work for one. The ACME protocol is not any more lenient in issuing certificates than traditional certificate authorities. |
**Erik St. Martin:** \[28:05\] It automates the process, really. If we think about the traditional approach of getting a certificate, they typically want you to add a DNS record to show that you have control of the authoritative zone, or they make you add something to the web page, or there's some sort of process to va... |
**Carlisia Thompson:** Exactly. But this process of validation, if there is a protocol and the company is following that protocol, we know that that protocol validates in a secure way and we can trust it. I think it was a very good initiative, because you can have implemented a validation process that's either manual, ... |
**Matt Holt:** Right. In fact, we saw a similar problem with StartEncrypt, where they had an issue with their API, a security issue, and they don't use ACME, they do something else. So you have to be careful, it's not easy. ACME is pretty good, it relies on the integrity of DNS, just like traditional domain-validated c... |
**Brian Ketelsen:** Alright, well, this is a good opportunity for us to take a break and thank our sponsor Equinox. Many of you probably create applications that you need to ship to end users or customers, and if you've been in that boat like I have, you'll know that there are two things that are pretty important: the ... |
The installation experience is dead simple because they create Debian, RPM, Microsoft Installer, Mac packages and they have a Brew Install option that lets your customers get your application pretty much any way that they're comfortable doing it. They also have a hosted download page for your application. So any way th... |
That second feature of keeping your customers up to date is probably the harder part of delivering your application and Equinox lets your programs self update, which is I think probably the neatest thing ever, because they just give you library code that you can use to automatically add an update flag to your command l... |
Now that we've talked about our sponsors, I have a question for Matt again, which is the economics of the certificate space. You know, just two years ago before Let's Encrypt existed or was doing anything, certificates, especially on the website, were insanely expensive and a big money maker. How do you feel the landsc... |
**Matt Holt:** \[32:08\] Well, I'm not a certificate authority, so I don't know financial numbers exactly, but I'm willing to bet that they're probably scrambling. A couple of certificate authorities I've observed have made rash moves in terms of public relations that I wouldn't deem wise or sensible, because I think t... |
I don't think that automated certificates, whether free or not, I don't think they're going to -- because ACME, by the way, it doesn't say the certificates have to be free, at least as far as I know. I don't think the automated certificates are gonna put CAs out of business. I do think it's going to make them more acco... |
There wasn't ever a whole lot of technical or business value in plain domain validated certificates, especially since everything on the CA side is automated; it was just the customer that had to mainly do everything. I think once everything rolls out as HTTPS, because certificates become ubiquitous, I think that once e... |
**Brian Ketelsen:** Well, didn't one of the web browsers just make that change recently? I wanna say maybe it was Chrome. There was an update I saw just a few weeks ago, that standard DV validated certificates were going to be shown gray and EV would be green. They'd still have the padlock, but I agree that the enhance... |
**Matt Holt:** Yeah, that's the plan. |
**Erik St. Martin:** I think I have two concepts there. One is the free certificates. What percentage of that is taking away from paid certificates? This may be new people coming on that didn't want to go through the burden of setting up certificates or financial pain for them and wildcard certificates because they wan... |
I don't think it's gonna put them out of business, but I don't think that they're gonna make the money that they currently are. And the other side of it is if TLS is almost free, maybe the domains cost more if they're wanting to keep the same income. It's kind of hard to tell. |
**Matt Holt:** Right, it will cause the CAs to have to be a little agile here to stay relevant. But again, extended validation is really valuable, you can't automate that either. So I say charge for that, and I think businesses will pay for that. |
**Brian Ketelsen:** As long as the consumers perceive value, they will. |
**Matt Holt:** Right. |
**Brian Ketelsen:** But as we educate more about what TLS is, what encryption is, what security is in a web browser, you know, maybe those extended enhanced validations matter less. It'd be interesting to see. |
**Matt Holt:** \[36:00\] It's possible. Yeah, it will be interesting to see what happens. |
**Erik St. Martin:** Now, before we move on to our news and interesting projects part of the show, I did wanna touch back on ACME for a second. We kind of talked about what the model is to manually validate your domain to get a certificate. Do you wanna walk us through how ACME does that? |
**Matt Holt:** Sure. So ACME relies again on the integrity of DNS and the spec presents three different challenges that you can solve to get a certificate to prove your ownership of domain name. So for example, Caddy will solve two of these challenges for you by default, just out of the box, it will just work. The thir... |
The HTTP challenge is basically where you serve up a resource at an HTTP endpoint on your server. The ACME CA will do an authoritative DNS lookup, make a request to your server for that special resource, and if it can find it there then it proves you own the machine or that you own the domain name, and so you can get t... |
Caddy does this one. It does the TLS SNI challenge as well, which is the same idea as the HTTP challenge, except that it performs a special TLS handshake. And if your server, which is the client, in this case, can complete that special handshake with the special server name in the SNI extension, then the ACME CA will v... |
So Caddy can do both of those for you by default, automatically. There are Go libraries that can do at least the HTTP challenge. That seems to the standard one. The problem though with these two is that it requires opening a port. The HTTP challenge requires Port 80 and the TLS SNI challenge requires port 443. Those ar... |
Then there is the third challenge, which is the DNS challenge. And this one, you have to set a record in your zone file on your domain name for a special name on your host, that validates that you own the DNS, that you have access to that. And the ACME server will perform an authoritative lookup for that special record... |
The downside is that you either have to do this manually or you have to give your ACME client credentials to your DNS provider, and they have to have to have an API to allow you to set records. Now unfortunately, lots of DNS providers have an API of some sort. Caddy, for example, ships with support for 10 DNS providers... |
Those are the three challenge types, and if you're having a hard time with Let's Encrypt or with the ACME protocol in general, I'm willing to bet it's probably because your tooling has not quite arrived yet or it's not mature yet, or you're asking a lot from the Let's Encrypt servers, and that's when people run into ra... |
**Erik St. Martin:** \[40:11\] So is there anything else that a listener should know about either Caddy or TLS or ACME before we move on? Is there anything else you'd like to add? |
**Matt Holt:** Encrypt - just use TLS. Do it right, do it well, look into the tools. We'll probably have links in the show notes for some of these TLS resources. |
**Erik St. Martin:** Yeah, we definitely will. |
**Matt Holt:** But if you think you don't need to encrypt, think again and think really hard about it. |
**Brian Ketelsen:** Yay! Retweet that, quote it. |
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