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I understand that browsers must trust a certificate authority (CA) to display a page using an SSL certificate without requiring the site visitors to trust the certificate. But I see certs sold by different companies at different prices (some even free) but as I understand it they are not as "good." If an SSL certificate is supported by a browser and makes a page encrypted, what makes one CA's certificates better than another CA's certificate?
These certificates differ on various aspects:
life time: the cheapest certificates usually have a short life time, e.g. expire after a year or so and need to be recreated. This is not primary a nuisance to make you buy better certificates, but the cheap guys usually don't care as much about security and thus these certificates have a higher chance to be compromised (e.g. private key stolen) and there should have a short life time to limit the damage the attacker could do. And in case the owner of the certificates notices and cares about the compromise the certificate needs to be revoked and added to a CRL (certificate revocation list) which can thus get really big - just look at the huge CRLs of GoDaddy.
wildcard and multiple names (subject alternative names): cheap certificates are restricted to a single host, wildcard or alternative names cost more. Usually companies rather by a certificate with multiple names or wildcards to avoid the hassle of maintaining multiple certificates, often it is also necessary if you offer the same site with multiple names (e.g. even example.com and www.example.com are different).
how much verification is really done: the idea is, that some CAs do a better verification of the owner of the certificate. This makes the certificate more expensive (somebody has to pay for the verification) but it also makes it more trustworthy. Of course this make only sense if the CA really checks the owner. The best known example for this are the "extended validation certificates" which show up in the browser as more trusted.
Apart from that, your browser trusts about 100 different CAs from a variety of countries. In the current PKI (public key infrastructure) there is no way to restrict the impact of each of the CAs, e.g. a chinese CA can issue certificates for google.com or an american CA can issue certificates for google.cn. There is also no foolproof collision management, e.g. a certificate for the same domain could be issued by multiple CAs at the same time and the browsers would accept it.
Moreover, each of these trusted root-CAs can issue any number of intermediate CAs which in itself could issue other intermediate CAs etc. Each of these intermediate CAs has all the capabilities to issue any certificate they want, e.g. recently a sub-sub-sub-sub CA of the french CA FGC/A issued "accidentely" certificates for google.com and others, see http://arstechnica.com/security/2013/12/french-agency-caught-minting-ssl-certificates-impersonating-google/.
And, there is no public list of all the certificates a CA issued, so you can be sure that some of them sell intermediate CAs to law enforcement and for other purposes (see also http://blog.spiderlabs.com/2012/02/clarifying-the-trustwave-ca-policy-update.html).
And, of course, CAs get also hacked, like DigiNotar and Comodo in 2011, where certificates for gmail, microsoft live etc where issued and actively used in attacks. And while DigiNotar got closed Comodo was probably too big to fail.
In summary: with the current PKI system the certificates you can trust the certificates like you would trust a combination of all the major goverments and companies - whatever this trust is :(
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I have an online shop and I've just installed a new SSL certificate and it was free. It does seem too good to be true. I'm a very cynical type of person.
I don't know about different types of SSL, but I just need to be able to accept payment data (I'm using a PayPal add-in on Opencart).
I got my certificate from letsencrypt and they don't explain much on there website.
But if you go to my website Gwenllian-retail you will see the certificate. Can I handle financial transactions with that?
If not what type of SSL do I need?
One does not need much money or complicated software to create valid SSL certificates. I could create my own with ease, if I wanted. In fact, I have done. There is no reason to think that LetsEncrypt certificates are somehow of a wrong kind.
The question is whether people will trust those certificates, and that comes back to whether they trust the Certificate Authority (CA) that signed them. If I sign my own certificate and present that to someone as proof of my identity then that other party has no more reason to trust that the data within accurately identify me than if I just told them directly.
LetsEncrypt serves as the CA for SSL certificates it provides. I have never relied on them for a certificate, but according to hosting company DreamHost, LetsEncrypt certificates are trusted by all major browsers. (LetsEncrypt makes the same claim about itself, too.)
Again, all this trust business is mostly about authentication: whether the entity that presents the certificate (your web site) is really the entity that it says it is. It is not about the nature or quality of the encryption with which the session is secured. That comes down to the capabilities of the two endpoints, and is largely independent of the certificate.
Let's Encrypt is a well known service backed up by many big players. So yes, it's OK to use it in on your site. BUT ! SSL certificate is not everything, it's only one of many shields to protect you application.
I have been reading up on the technical basics of how SSL works (which was surprisingly hard to find inside the ocean of laymen/non-technical articles/tutorial/videos out there). I have 3 small questions that in and of themselves felt too small to clutter SO with but as a whole I think provide some insight into how SSL works and address issues that don't seem to be well-documented:
Why (not when or how!) do SSL certificates expire? These are just public/private key pairs operating on a cipher/algorithm like AES. I assume there's a financial/business incentive behind the scenes here?!?
How many SSL certificates does an organization need? And before you say "that depends on your organization", I guess at the core of this question is: what driving factors make a company say, oh, I guess we're going to need another cert, or 10 more certs, etc. In other words: why is 1 cert often not sufficient for an organization??
Why does a company ask a CA for a root certificate and then get child certificates off of that root? What benefits does this "Certificate Tree" provide? (As opposed to just getting separate certs.)?
Thanks in advance!
1) Why do SSL certificates expire?
When a certificate expires, you're basically saying that this public/private keypair has been abandoned. Technically, you can still use this certificate to encrypt data, but the expiration date is there to mitigate revocations among other things. Additionally, however, in the X.509 spec there are specific reasons outlined for expiration:
4.1.2.5 Validity
The certificate validity period is the time interval during which the
CA warrants that it will maintain information about the status of the
certificate.
CAs publish revocation status information about a certificate and that means they need to keep track of them. When a certificate expires, the CA has done their part for the term of the certificate and stops tracking information for that certificate. You are essentially paying the CA to say with authority that this certificate is valid.
There are other reasons for expiration too. If I was still using a certificate signed in 2002 (which would be possible), the level of encryption probably wouldn't be up to standards used today. By setting an endpoint for the certificate, you are also setting a date on which you need to upgrade.
Now, of course, I don't think you can deny one of the biggest motivators behind the expiration is money [citation needed], but there are at least some technical and reasonable ideas behind it.
2) How many SSL certificates does an organization need / what driving factors help them decide?
It does depend on your organization. A traditional SSL certificate is matched to a domain name. However, anything can be signed with a key pair (developer certificates, etc.). So, for SSL, it'll depend on the number of domains you want to protect. For a traditional cert, www.domain.com and example.domain.com are completely different entities. There are other types of certs that can purchased, like wildcard certs, etc. that will depend on the needs of your business. Seriously, you can get incredibly complex or incredibly simple. Here's a rundown on some of the basic and different types for protecting a website: SSL Certificate Types
3) What benefits does [having a] "Certificate Tree" provide, as opposed to just getting separate certs?
You are basically saying that you trust this CA to generate certificates. That's why browsers have to have the root CA installed to accept a certificate. They are saying, "I trust this authority has only signed certificates for valid and trusted sources."
In practice, it ends up not being the case as a lot of CAs don't rigorously check who they are giving certificates to before issuance. Not always, but it does mitigate some of the danger. The problem is when the CA root certificate private key is compromised because then anyone can fake a legitimate certificate.
Hopefully this answers some of your questions.
I'm developing software which will be deployed using clickonce (on the website foo.com), and which will then connect to my server using WCF with an encrypted transport
So I need an SSL certificate which will :
Identify my foo.com website has really being my website
Identify the exe I deploy using clickonce as being genuine
Identify my application server has really being my application server.
I also want my SSL certificate to be signed by an authority known to the public (ie, firefox or windows won't ask the user to install the authority's certificate first !)
What SSL certificate would you buy?
I've browsed the Verisign website, the "Secure Site EV" certificate costs 1150€ a year (the "Pro" version seems useful only for compatibility with older browsers)
It sounds like you're looking for two different types of certificates:
1 - SSL Certificate - for authentication of your website/application server.
2 - Code Signing Certificate - for integrity/authentication of the exe you deliver.
Typically those are two different certificates, with two different certificate profiles. At the very least, you need one certificate with two different key usages or extended key usages.
A few thoughts in no specific order:
Check your targeted browsers, they should each have a set of preconfigured root certificates - those are the most widely recognized public certificate sources. I'd probably check both Firefox and IE. Certificate vendors known to me as big names are - Versign, GeoTrust, RSA, Thawte, Entrust. But there's also GoDaddy and many others. Anything that comes in the delivered browser as a Trusted Root Certificate, will allow you to connect to your users without additional greif.
I suggest Googling for both "code signing certificate" and "SSL certificate".
How you configure your site will determine whether or not your website is validated or your authentication server is validated. If the certificate is stored on the apps server, then your user is getting SSL encryption all the way to the server. But many sites put the SSL certificate a little farther forward - like on a firewall, and then stage a collection of apps servers behind it. I don't see a security flaw in that, so long as the networking is carefully configured. To the outside users, both configurations will look the same - they'll get the lock on their browsers and a certificate that tells them that www.foo.com is offering it's credentials.
I'm seeing pretty great deals for SSL Certificates:
- GoDaddy - $12.99
- Register.com - $14.99
But they aren't necessarily code signing certifiates. For example, while GoDaddy's SSL Cert is $12.99, their code signing certs are $199.99! That's part of many certificate vendors business models - lure you in with cheap SSL Certs, and make you pay for code signing. A case could be made that code signing certificates are relatively higher liability. But also... they have to subsidize the cheap SSL certs somehow.
Theoretically, it should be possible to make a certificate that does both code signing and SSL, but I'm not sure you want that. If something should happen, it would be nice to be able to isolate the two functions. Also, I'm pretty sure you'd have to call the certificate vendors and ask if they did this, and if they don't, having them do it will likely jack up the price quite high.
As far as vendor, things to consider:
The technology is pretty much all the same. These days, aim for a minimum of 128 bit keys, I'd probably bump it up to 256, but I'm paranoid.
Beyond browser acceptabiliy, the only reason to pay more would be name recognition. Among the paranoid security wonks, I'd expect RSA, Thawte, Verisign and GeoTrust to have very good reputations. Probably EnTrust, too. This probably only matters if you are dealing with a security focused product. I think your average user will not be so aware.
From a security geek perspective - you're only as safe as the security of your Root CA (Certificate Authority). For the truly paranoid, the thing to do would be to dig into the background material of how the company hosts its root and issuing CAs, how are they physically securited? network security? personnel access control? Also - do they have public CRLs (Certificate Revocation Lists), how do you get a cert revoked? Do they offer OCSP (Online Certificate Status Protocol)? How do they check out certificate requestors to be sure they are giving the right cert to the right person? ... All this stuff really matters if you are offering something that must be highly secure. Things like medical records, financial managment applications, tax information, etc should be highly protected. Most web apps aren't so high risk and probably don't require this degree of scrutiny.
On that last bullet - if you dig into the Verisigns of the world - the very expensive certs - you're likely to see the value. They have a massive infrastructure and take the security of their CAs very seriously. I'm not so sure about the super-cheap hosting services. That said, if your risk is low, US$300 for an SSL Cert doesn't make much sense compared to US$12.99!!
So for web site / application servers you need an SSL certificate. You do not need an EV certificate. I've used ones from QuickSSL for this, as unlike some of the other cheap certificate providers they don't require the installation of an intermediate certificate on the server - that's a no-one for me.
For signing applications that's a different type of certificate altogether (kind of, it's still an X509 certificate, but the one you use for your web site is not one you can use to sign an application). You need an authenticode signing certificate from the likes of Verisign or Globalsign. These are a magnitude more expensive than a plain old SSL certificate and require you to be an incorporated company and produce those documents.
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I would like to have the authentication and registration parts of my website encrypted (for obvious reason). This site is currently and older site which some friends and I started in middle school and still use today. I may or may not register it to be a Non-Profit Organization in the near future, but either way, a CA costs money and the organization doesn't have any and we are currently college kids.
Verisign is unreasonable and GoDaddy is $30/year. GoDaddy isn't too unreasonable, and I think their certs are accepted by most web browsers. The thing with GoDaddy is that I don't know why they have different SSL products (i.e.: why is it cheap to not verify me? does this have any implications on the cert and how the browser treats it if it just contains a domain name?)
Also, is there an issue with using my own cert? Could the login page be http, and have a line stating that I use a self-signed cert and here is it's fingerprint and then post the form to an https page? Safari's method isn't too bad or sound too scary. I'm afraid, however, that firefox 3's method will scare people away and give me a tonne of emails saying that my site is being hacked or something. I don't know how IE responds to self-signed certs. (There is also the issue of why pay for something I can create myself with no effort, but I'm not going to pose the philosophical part of it, this is a more practical question.)
In sum, do I give GoDaddy $30 a year or do I just tell people in a small paragraph what I'm doing and give the few people that will actually want my fingerprint it?
Edit: Some on a forum I was reading for more info mentioned that GoDaddy certs are only given if it's on a GoDaddy server, which this isn't. Two things: (1) is this true? and There are other CA's at about the same price, so the argument should still be the same.
There's a common misconception that self-signed certificates are inherently less secure than those sold by commercial CA's like GoDaddy and Verisign, and that you have to live with browser warnings/exceptions if you use them; this is incorrect.
If you securely distribute a self-signed certificate (or CA cert, as bobince suggested) and install it in the browsers that will use your site, it's just as secure as one that's purchased and is not vulnerable to man-in-the-middle attacks and cert forgery. Obviously this means that it's only feasible if only a few people need secure access to your site (e.g., internal apps, personal blogs, etc.).
In the interest of increasing awareness and encouraging fellow small-time bloggers like myself to protect themselves, I've written up a entry-level tutorial that explains the concepts behind certificates and how to safely create and use your own self-signed cert (complete with code samples and screenshots) here.
The SSL certificate solves two purposes: encryption of traffic (for RSA key exchange, at least) and verification of trust. As you know, you can encrypt traffic with (or without, if we're talking SSL 3.0 or TLS) any self-signed certificate. But trust is accomplished through a chain of certificates. I don't know you, but I do trust verisign (or at least Microsoft does, because they've been paid lots of money to get it installed in their operating systems by default), and since Verisign trusts you, then I trust you too. As a result, there's no scary warning when I go to such an SSL page in my Web browser because somebody that I trust has said you are who you are.
Generally, the more expensive the certificate, the more investigating that the issuing certificate authority does. So for the Extended Validation certificates, the requesters have to submit more documents to prove that they are who they say they are, and in return they get a bright, happy green bar in modern Web browsers (I think Safari doesn't do anything with it quite yet).
Finally, some companies go with the big boys like Verisign purely for the brand name alone; they know that their customers have at least heard of Verisign and so that for people shopping on their online store, their seal looks a little less sketch-ball than, say, GoDaddy's.
If the branding is not important to you or if your site is not prone to phishing attacks, then the cheapest SSL cert that you can buy that has its root installed in most Web browsers by default will be fine. Usually, the only verification done is that you must be able to reply to an e-mail sent to the DNS's administrative contact, thus "proving" that you "own" that domain name.
You can use those cheap-o certificates on non-GoDaddy servers, sure, but you'll probably have to install an intermediate certificate on the server first. This is a certificate that sits between your cheap-o $30 certificate and the GoDaddy "real deal" root certificate. Web browsers visiting your site will be like "hmm, looks like this was signed with an intermediate, you got that?" which requires may require an extra trip. But then it'll request the intermediate from your server, see that it chains up to a trusted root certificate that it knows about, and there is no problem.
But if you are not allowed to install the intermediate on your server (such as in a shared hosting scenario), then you are out of luck. This is why most people say that GoDaddy certs can't be used on non-GoDaddy servers. Not true, but true enough for many scenarios.
(At work we use a Comodo certificate for our online store, and a cheapo $30 GoDaddy cert to secure the internal connection to the database.)
Edited in italics to reflect erickson's insightful clarifications below. Learn something new every day!
Get a certificate from Let's Encrypt, a free CA this new decade, which is widely supported by browsers.
I haven't tried them yet, but StartCom was mentioned in a response to a similar question. Apparently you can get a one year certificate for free, and it's accepted by Firefox 3.
Even if you have to pay, I would suggest using a CA rather than self-signed certificates. Some people won't see your explanation, and a fake site could post their own fake certificate's fingerprint just like you propose. I doubt the average user knows what a certificate fingerprint is or how to check it.
Instead of creating a self-signed cert, create a self-signed CA, and sign your HTTPS certificate with that. It's easier to ask users to install a CA than a single server cert, and you can create new certs (eg. for subdomains, or to update expired certs) without users having to install a server cert again.
You can then decide later whether it's worth the $30 to switch from a cert signed by your own CA to the same cert signed by GoDaddy or whoever.
Either way, don't have an HTTP page with a form posted to HTTPS. The user cannot see that that's where it's going; they'd have to view source to check the form hasn't been hijacked to point elsewhere and no-one's going to do that. You would have to have an HTTP front page with the CA link and a separate link to the HTTPS login form.
Asking users to install a CA with a cert downloaded via plain HTTP is a bit naughty: if there were a man-in-the-middle they could replace your CA on the fly and hijack the ensuing HTTPS connections. The chances of this actually happening are quite low as it would have to be a targeted attack as opposed to plain old automated sniffing, but really you ought to be hosting the CA download link on some other HTTPS-protected service.
Customer acceptance is a matter only you can answer, knowing who your users are. Certainly the Firefox interface is excessively scary. If CAs like GoDaddy are down to $30 these days I would probably go for it; it used to be a lot, lot worse.
Assuming support on old and niche browsers is not much of an issue, just go for the cheapest CA available. You are supposed to be paying to have the CA properly verify who you are, but in practice that's not the way it works and it never has been, so paying extra for more thorough checks gets you almost nothing. Verisign's extortionate prices survive through corporate inertia alone.
CAs are there to receive money for doing nothing but owning a few hundred bits of private key. The identity-verifying stuff that was supposed to have been part of the CA mandate has been moved to EV certificates. Which are even more of a rip-off. Joy.
Self-signed certificates are insecure. Yes, really. "At least it's encrypted" isn't helping at all. From the article:
World-class encryption * zero authentication = zero security
If your website is for you and a few of your friends, then you might create your own CA and distribute your certificate to friends.
Otherwise either get a certificate from known CA (for free) or don't bother with self-signed certificates at all, because all you'd get is a false sense of security.
Why just encrypted traffic is not secure? You're always allowing the other end to decrypt your traffic (you have to, otherwise you'd be sending gibberish).
If you don't check who's on the other end, you're allowing anybody to decrypt your traffic. It doesn't make a difference if you send data to an attacker securely or not securely — the attacker gets the data anyway.
I'm not talking about checking whether e.g. paypal.com belongs to a trustworthy financial institution (that's a bigger problem). I'm talking about checking whether you're sending data to the paypal.com, or just to a van around the corner that sends a certificate saying "yeah, I'm like totally paypal.com and you have my word that it's true!"
I just finally broke down and switched my server from self-signed to a GoDaddy cert last night and it wasn't that big a deal, aside from their process not being as clear as it could be. $30/year is a reasonable cost and using the cert on a non-GoDaddy server is not an issue.
If you're going to be talking SSL to the public, get a real cert signed by a real CA. Even if you're working for minimum wage, you'll save more than $30/year worth of wasted time in dealing with user fears or distrust, and that's even before considering any possible lost revenue due to them being scared away from your site.
To answer your question about Internet Explorer, it will warn users about any site whose certificate is not signed by an IE-known (unfortunately called "trusted") CA. This includes for your own CA and for self-signed certificates. It will also make a warning if the domain in the certificate is not the one being accessed.
If this is a private site, you may not care so long as you are getting link-level encryption (and are you that fearful of someone sniffing your traffic?). If there is public access and you want SSL, then get a signed certificate from a recognized CA, as others have already advised.
If that van around the corner is capable of hijacking your internet connection already, you've got worse problems than self-signed certificates.
Banks should use client certificates for authentication. That would make it impossible for that van to do anything.... since it doesn't have the banks private key.
Self-signed certs are perfectly fine... assuming your internet connection hasn't been compromised. If your connection has been compromised... you're probably dogged anyway.
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I want to buy a 128bit SSL certificate for a website selling services. I checked http://www.rapidssl.com/ssl-certificate-products/ssl-certificate.htm and http://www.geotrust.com/ssl/compare-ssl-certificates.html. Why are the prices for QuickSSL (Geotrust, $249) and RapidSSL (rapidSSL, $69) so different? Is there any particular reason for this or it's just marketing?
RapidSSL says the following:
However it is our opinion that sites conducting more than 50 transactions will require a Professional Level SSL certificate due to the increased likelihood that the website's customers will expect SSL from a highly credible and established SSL provider and well
known internationally accepted SSL brand.
(by "professional level SSL" they mean Geotrust certs)
P.S. will users really pay attention to the SSL issuing authority brand name?
The job of the SSL certificate authority(CA)/provider is to validate your organizational identity so that when customers access your web site, they not only get the padlock for security, but they know that your identity as the fully qualified hostname are authentic and not some phishing scam.
True, most all users look no further than the padlock indicating secure connection to their bank web site, email, etc. However, if any CA were to become compromised, all browsers who trust that CA would be vulnerable, because an attacker could forge a certificate for any domain, including yours. Your choice of certificate provider has no bearing on this. I have yet to hear about this actually happening. MITM attacks are a big deal now with wireless hotspots becoming more and more prevalent.
One more thing is browser compatibility. You would expect that your newly purchased cert be compatible with every modern browser. This is because they are all loaded with a list of root CA certs that trust a select list of SSL certificate authorities. If you buy from a CA that is not on that list, all your client browsers will get a security warning that the site's cert is not trusted. Just doublecheck that RapidSSL, Geotrust, or whoever you go with is in the list of all the browsers you care about. (e.g. for Firefox, it's at Tools/Options/Advanced/Encryption/View Certificates/Authorities tab)
In the end, just get the cheapest one that gives you the level of encryption you want. It'll get the job done. Check with your web host provider. They may have discounts.
To clarify, both are owned by Geotrust(R) . One difference is that Geotrust certificates use "Geotrust" root, and RapidSSL certificates use "Equifax" root, which will be shown in the certificate info "Issued by".
I know this has an accepted answer already, but there is another aspect.
The more expensive SSL certificates usually have a better warranty when it comes to fraud. A lower cost SSL cert may cover $10,000 worth of fraud whereas a higher cost SSL cert may cover you for $100,000, for example.
they both do the same job, just brand perception i guess
honestly i don't think the end user would even notice. as long as they see the little padlock they will be happy
ps. godaddy certs are cheaper
This has a good overview of the RapidSSL faqs.
This will give you the same for the QuickSSL.
The main difference in these certificates is the amount of verification during purchase. The encryption is basically the same for both.
As for the warranty mentioned above, as far as I understand this is a warranty to the "end user" in case the certificate authority issues a certificate to a fraudulent person/domain. It is not a warranty to the website owner.
Pretty late to the game but there is one other detail worth noting here--RapidSSL is not on IE8's list of trusted authorities.