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While shopping for a basic SSL cert for my blog, I found that many of the more well known Certificat Authorities have an entry-level certificate (with less stringent validation of the purchaser's identity) for approximately $120 and up. But then I found that Network Solutions offers one of these lower-end certs for $29.99 (12 hours ago it was $12.95) (4-year contract).

Is there any technical security reason that I should be aware of that could make me regret buying the lowest end certificate? They all promise things like 99% browser recognition, etc. I'm not asking this question on SE for comparison of things like the CA's quality of support (or lack thereof) or anything like that. I want to know if there is any cryptographic or PKI reason so avoid a cert which costs so little. It, like others, says that it offers "up to 256 bit encryption".

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Relevant - security.stackexchange.com/questions/13453/… –  Kyle Rozendo Aug 14 '12 at 21:28
"it offers "up to 256 bit encryption" no the CA or cert does not! Your TLS server does. –  curiousguy Aug 15 '12 at 1:04
Added trust, because the trust you have in the third party should be relevant here. –  curiousguy Aug 15 '12 at 1:24
If you still decide to go for the 'cheapest', do remember that you can get them for free (startssl.com being one such provider) –  Andy Smith Aug 15 '12 at 13:13
Talking about 256 bit encryption in the context of certificates is nonsense. That part of SSL is completely independent of certificates. –  CodesInChaos Oct 25 '12 at 21:35

11 Answers 11

Because domain-validated certificates may scare Comodo Dragon users.

Consider these five tiers of HTTP security (not an official list):

  1. No TLS (http:)
  2. TLS with a certificate that is self-signed or from an otherwise unknown issuer
  3. TLS with domain-validated certificate from a known issuer (organization not part of certificate)
  4. TLS with organization-validated certificate from a known issuer (organization name in certificate)
  5. TLS with Extended Validation certificate from a known EV issuer (organization name and address in certificate)

Certificates that you buy from a commercial CA will be 3, 4, or 5. Most web browsers allow all but 2 with no interstitial warning, even though 2 is better than 1 in resistance to passive attacks. But the Comodo Dragon web browser warns on 3 as well. It displays an interstitial warning screen when viewing any HTTPS site that uses a domain-validated certificate, which begins as follows:

It may not be safe to exchange information with this site

The security (or SSL) certificate for this website indicates that the organization operating it may not have undergone trusted third-party validation that it is a legitimate business.

This is intended to stop attackers who register a domain bankofamerrica.example for "Banko Famer Rica", put up colorably legit content about Costa Rica, buy a certificate for that domain, and then change it to a site that impersonates Bank of America. But it's been seen to display this message even for Facebook.

To not scare users of Dragon, you need to avoid domain-validated certificates. But you don't need to buy an EV certificate. Just make a list of CAs willing to sell your organization an organization-validated certificate whose root certificate is in all major browsers. Then there's no technical security reason not to buy the cheapest one.

If you're operating your blog as an individual, you may not qualify for an organization-validated certificate from any CA. In this case, you just have to live with the warning in Dragon, and you can just go with a cheap domain-validated certificate like the one StartSSL offers.

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I'm sure this is all technically true, but talking about your self-invented 5 tiers of security does not answer the question. And disclosure would be used when you are a certificate reseller, not when you (like most of the people here I think) got a website with a (hopefully signed) certificate. –  Luc Dec 2 '14 at 18:18
@Luc The tiers are just background info to provide a means to compare five possible situations, three of which result from buying a certificate. I've fixed the answer to lead with the tl;dr version. –  tepples Dec 3 '14 at 1:09
I don't like this answer because it implies something called "Comodo Dragon" is relevant to the certificate buying process. If I code up a browser this weekend and warn on all but 5, that does not mean it matters for OP since no one will be using my browser just like no one uses Comodo's browser. I won't down-vote because I believe you answered in good faith and there is some value in this answer. –  Tom Dworzanski Mar 11 at 9:36

No matter which CA you go with, your users' assurance that they're actually communicating with your site and not an attacker is only as good as the worst CA their browser trusts - an attacker who wants to forge a certificate can shop for a CA with bad practices. So I don't see any plausible argument that your choice of CA impacts your site's security, unless you choose a CA that generates private keys for you rather than signing a key you provide, or that disallows large key sizes.

Other than that, as others have said, it's probably a good idea to avoid CA's whose mix of bad practices and small size makes it plausible that their trust might be revoked by one or more browsers, since this would impact the accessibility (and public perception) of your site.

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This is an excellent answer, made all the more excellent by your inclusion of the users' perception. Perception is an ever present, if unwelcome, aspect of the security posture of any information system. –  Luke Sheppard Sep 17 '14 at 19:34

SSL certificate is used for two purposes.

  • One is securing online transactions and private information which is transmits between a web browser and a web server.
  • Second is Trust, SSL is used for increase customer confidence. SSL proves secure session of your website, it means your customer trust on your website.

Each certificate has own validation process and following this process certificate authority validates your business reliability and send certificate for your website.

A basic cheap ssl certificate only validates your domain authority and authenticated using the approver email verification system. Approver can easily get this certificate in just minutes with generic email address.

OV and EV SSL certificates plugged with customer’s trust and through it’s strictly authentication process it gives highest level of trust. EV SSL validates manifold components of identifying your domain and business information. It follows manual verification process and during this process system fails to verify or system defendants your business for potential false action then your order may be lined up for manual review.

Main difference in trust factor and brand reputation, while your customer see the green address bar in your browser then they feel more secure and encourage to make transaction. Otherwise, some differences between other features like encryption, browser compatibility, key length, mobile supports, etc.

Otherwise certificates warranty explains differences. Certificate authorities provide extended warranty ($1K to $1.75M) against mis-issuance of an SSL certificates which explains the worth of your investment for website security.

While focus on price of certificate, it doesn't matter where to buy your certificate – certificate authority or authorized reseller. Authorized reseller offers same SSL products, same security features, better support at reasonably priced.

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Thank you for your answer, and welcome to Security.SE! Since you are employed at an authorized SSL reseller, and your answer mentions using resellers favorably, can I encourage you to include your affiliation in your answer, to be on the safe side? I know you're not promoting any specific product, so this is a gray area, but this is something your employer has a financial interest in, it feels better to disclose the potential bias just to be safe. (See also security.stackexchange.com/help/behavior for the official policy, or meta.stackexchange.com/a/145588/160917.) –  D.W. Jun 24 '14 at 0:54

In light of the latest NSA revelations, I'd say the entire concept of commercial Root CAs is fundamentally flawed and you should just buy from the cheapest CA whose root certificate is installed in browser and operating system trust chains.

In practice, we need multiply-rooted certificate trust chains instead of the current singly-rooted trust chains. That way, instead of ignoring the real power of governments to "coerce" commerical providers - you'd simply get your certificate signed by multiple (preferably antagonistic) governments. For example, have your Bronies vs Juggalos cage match website signed by USA, Russia, China, Iceland and Brazil. Which might cost more but would really reduce the likelihood of collusion.

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Thank you, that's my new example website. –  Ian Jan 20 '14 at 4:28

From a pragmatic standpoint for a site with standard-type users, the only criteria that matters for an SSL certificate is "is it supported by the browsers that my users will use to access the site". As long as it is, you're fine with it being as cheap as possible.

A while back a potential differentiator was whether the certificate was EV SSL or not but to be honest I've not seen great user awareness of that, so unlikely to be worth the money.

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Ignoring the technical aspects of certificate encryption, the issue to consider is trust and reputation. If you are only concerned about encryption of the traffic, then you can use a simple self signed certificate. On the other hand, if what you want to achieve is to provide a level of trust that you or your site really is who/what it claims to be, then you need a certificate from a certificate authority which people trust.

The CA achieves this level of trust through vetting of the people they sell certificates to. Many of the cheaper certificate providers achieve their lower prices by reducing their operational overheads and this is often done by having less vigorous vetting processes.

The question should not be "Who is the cheapest certificate provider", but rather "Which certificate provider has the necessary reputation and level of trust which users or potential users of my service will accept".


P.S. Unfortunately, to some extent, the whole model is broken anyway. Few users even check to see who the CA is that issued the certificate and have little knowledge or understanding of the chain of authority involved.

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I'd go as far as to say almost no users will ever check the issuer and even if they did wouldn't have a clue who was good/bad/indifferent.. –  Rоry McCune Oct 25 '12 at 22:13
Self-signed certificates for one's own personal web site are a PAIN. Some OSes (certain versions of Android, for instance) I have been unable to install a certificate, even having to do this for every device I use regularly wastes a lot of time, and have to click past a warning on 20 different tabs when chrome restart is a pain too. –  Michael Apr 9 '14 at 22:27

From a technical standpoint, the only thing that matters is browser recognition. And all of the trusted authorities have very nearly 100% coverage.

I could say more, but to avoid duplicating effort here's a nearly-identical question with a lot of well-reasoned responses: Are all SSL Certificates equal?

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For the purposes of this discussion there are only a couple differences between web signing certificates:

  1. Extended vs standard validation (green bar).
  2. Number of bits in a certificate request (1024/2048/4096).
  3. Certificate chain.

It is easier to set up certificates with a shorter trust chain but there are inexpensive certs out there with a direct or only one level deep chain. You can also get the larger 2048 and 4096 bit certs inexpensively.

As long as you don't need the extended validation there is really no reason to go with the more expensive certificates.

There is one specific benefit that going with a larger vendor provides - the more mainline the vendor, the less likely they are to have their trust revoked in the event of a breach.
For example, DigiNotar is a smaller vendor that was unfortunate enough to have their trust revoked in September 2011.

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+1 for mentioning vendor trust issues –  MrGlass Aug 14 '12 at 20:23
"The more mainline the vendor the less likely they are to have their trust revoked in the event of a breach." correct, but "too big to fail" principle stinks! :( –  curiousguy Aug 15 '12 at 1:06
@MrGlass It is not so much trust in the CA as trust that the very big CA will not be punished, ever, for doing evil things because that would punish its clients too. It's true and it stinks. –  curiousguy Aug 15 '12 at 1:08

In general the two things which you probably can pass on are the EV (since that is just the green bar gimmick) and also SGC does not really provide any real benefit today (since it only applies to browsers from the days of IE5 and before)

This site provides a good overview of why to avoid SGC: http://www.sslshopper.com/article-say-no-to-sgc-ssl-certificates.html

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"Comodo since they're a well known brand" well known for scandals! –  curiousguy Aug 15 '12 at 1:02
@curiousguy - Thank you for pointing that out, and your answer below. I've edited my post accordingly and I'm going to adjust my own policies also. Thanks! –  theonlylos Aug 15 '12 at 1:53
You are welcome. +1 for "green bar gimmick" –  curiousguy Aug 15 '12 at 2:05

Good stuff in other answers, let me add some remarks about proper CA behaviour.

If the CA has an history

  • of lack of security policy enforcement,
  • of violation of "browser approved CA" agreement,
  • of signing of non DNS names using their official root certificate (like IP addresses, or non existent DNS names f.ex. bosscomputer.private),
  • of lack of transparency about its behaviour and its resellers,

and the end user (like me) inspects your certificate, and knows about this, that might reflect badly on you. Especially any CA that is a subdivision of a company also in the business of connexion interception.

When I see USERtrust or COMODO or Verisign in a certificate chain, I am not positively impressed.

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Can you suggest any ways that a potential customer can identify which CA's have a history of the sort of improper behavior that you mention? (Google for mentions in the press?) –  D.W. Aug 15 '12 at 16:32
What did Comodo and Verisign do wrong? –  Joe Z. Apr 13 '14 at 1:08

For a domain validation certificate, the only thing that matters is whether browsers accept the certificate as trusted. So, take the cheapest cert that is trusted by all browsers (or all browsers you care about). There is no significant cryptographic reason to prefer one supplier over another.

(You will of course have to pay more for an extended validation certificate, but that's an entirely different class of certificate. I think you already know that.)

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"the cheapest cert that is trusted by all browsers" and does not have bad things associated with its provider name? –  curiousguy Aug 15 '12 at 1:04

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