Certificate authorities verify the owner information of certificates by signing them.

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163
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7answers
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How do certification authorities store their private root keys?

Knowledge of a CA private key would allow MitM attackers to transparently supplant any certificates signed by that private key. It would also allow cyber criminals to start forging their own trusted ...
140
votes
4answers
16k views

Is there anything preventing the NSA from becoming a root CA?

There are now tons of Certification Authorities (CAs) that are trusted by default in major OS's, many of which are unrecognizable without online lookup or reference. While there have been attempts ...
108
votes
7answers
8k views

How do I report a security vulnerability about a trusted certificate authority? [duplicate]

I stumbled across a huge security vulnerability in a Certificate Authority that is trusted by all modern browsers and computers. Specifically, I am able to get a valid signed certificate for a domain ...
80
votes
11answers
20k views

Is there any technical security reason not to buy the cheapest SSL certificate you can find?

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 ...
65
votes
4answers
20k views

Are all SSL Certificates equal?

After running a few tests from Qualsys' SSL Labs tool, I saw that there were quite significant rating differences between a GoDaddy and VeriSign certificate that I have tested against. Are all SSL ...
63
votes
10answers
14k views

Why do we not trust an SSL certificate that expired recently?

Every SSL certificate has an expiration date. Now suppose some site's certificate expired an hour ago or a day ago. All the software by default will either just refuse to connect to the site or issue ...
50
votes
12answers
6k views

How feasible is it for a CA to be hacked? Which default trusted root certificates should I remove?

This question has been revised & clarified significantly since the original version. If we look at each trusted certificate in my Trusted Root store, how much should I trust them? What factors ...
49
votes
2answers
3k views

Why does Windows Ship with Expired SSL Certificates?

I am cleaning up the certificate stores on my Windows machines, and considering which certificates I should keep, and which ones I should delete. Why does a fresh install of Windows Server 2012 R2 ...
33
votes
4answers
5k views

What alternatives are there to the existing Certificate Authority system for SSL?

Whilst the current CA system works very well for a lot of people, it does put a lot of power into individual CAs' hands, and makes a CA hack potentially devastating for customers and business. What ...
29
votes
5answers
14k views

Where to get an SSL certificate for personal website?

I would like to use https to login to my personal webpage (which is on shared hosting). So I went over to google and started searching for sollutions. Eventualy I found out that I need an SSL ...
28
votes
6answers
5k views

Does it matter which Certificate Authority I source my SSL Certificate from?

To secure my web site with HTTPS, does it matter which company I source my SSL certificate from, or just that the browser recognizes it? From the Area51 proposal.
27
votes
2answers
3k views

Is it safe to send SSL certificates via email?

I just ordered a cheap Comodo PositiveSSL Certificate via a UK reseller, and I was rather surprised to find that the following files were emailed to me automatically, in a zip file: Root CA ...
27
votes
4answers
2k views

Can any CA sign any domain?

Can any CA sign any cert for any domain? If the answer is yes, what prevents having two different CAs creating a valid cert for the same domain? Does that mean that the whole TLS security has the ...
23
votes
4answers
9k views

Are there technical disadvantages in using free ssl certificates?

Note this question is related, except this one is about free SSL certs. There are providers who are offering totally free entry-level SSL certs (like StartSSL). I was wondering if they are ...
22
votes
1answer
386 views

Are there security design weaknesses in the EFF Sovereign Keys proposal?

In response to SOPA and a number of high profile security breaches at certficate authourities in 2011, the EFF has released a soverign keys proposal: ...
21
votes
3answers
31k views

Expired SSL Certificate Implications

What are the security implications of an expired SSL certificate? For example if an SSL certificate from a trusted CA has expired will the communication channel continue to remain secure?
20
votes
2answers
8k views

Why is Symantec/Verisign CA appearing as an invalid authority? [closed]

Typical browsing to www.BankOfAmerica.com got me an ERR_CERT_AUTHORITY_INVALID error. This was with an up-to-date production version of Google Chrome for Mac. I tried with Safari, and got the same ...
19
votes
4answers
3k views

Why does Facebook serve several SSL certificates?

Facebook seems to be alternately serving two SSL certificates, one from DigiCert and one from VeriSign. There are only two reasons for this that I can think of: They're in the middle of a ...
19
votes
4answers
22k views

how digital signature verification process works

I am not able to understand that how the digital signature is verified. I know that digital signature will be attached to the message and sent by sender to receiver. then receiver uses the public key ...
18
votes
4answers
12k views

Checklist on building an Offline Root & Intermediate Certificate Authority (CA)

Microsoft allows a CA to use Cryptography Next Generation (CNG) and advises of incompatibility issues for clients that do not support this suite. Here is an image of the default cryptography settings ...
18
votes
1answer
15k views

What is the actual value of a certificate fingerprint?

In a x509 digital certificate there is a "certificate fingerprint" section. It contains md5, sha1 and sha256. How are these obtained, and during the SSL connection, how are these values checked for?
17
votes
3answers
2k views

What are the risks of a Certificate Authority hack for 'the average user'?

Recently the DigiNotar CA was hacked, and rogue certificates were issued. Since they also issue certificates on behalf of the Dutch government, the government made a statement about it as well, ...
17
votes
3answers
874 views

Can a nation-state adversary perform a MITM attack by compelling a CA to issue them with fake certs?

As I understand it, with any encryption system based on a trust chain / CAs (eg SSL, TLS, S/MIME), it would be possible for a nation-state adversary (such as the NSA) to compel the CA to issue them ...
17
votes
1answer
17k views

Configure SSL Mutual (Two-way) Authentication

A lot of tutorials, a lot of pages, a lot of question and they differ in implementation of this issue "Configure SSL Mutual (Two-way) Authentication". I have to do it with Linux, and I don't know from ...
16
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3answers
3k views

What happens when an Intermediate CA is revoked?

Currently I'm working on a certificate manager that allows our product to securely connect to remote webservices (over TLS/SSL). For security, we use Certificate Revocation List checking (or ...
16
votes
9answers
899 views

How does SSL/TLS PKI work?

We have lots of questions that address portions of SSL/TLS as it relates to PKI, but none of them seem to bring everything together. A canonical answer that we can point people to I think would be ...
16
votes
2answers
6k views

What are the advantages of EV Certificate?

What are the various advantages of using extended validation (EV) certificates than normal certificates which also provide comparatively high degree of encryption like RC4, 128 Bit? I know that the ...
15
votes
2answers
680 views

How can I prevent that my users get a certificate issued for my domain on my behalf?

I have a domain, where some other users have access to upload files, use email, use XMPP, etc. How can I prevent that these users go to a certificate authority and get a certificate for my domain? ...
15
votes
5answers
4k views

Are self-signed certificates actually more secure than CA signed certificates now?

Are self-signed certificates actually more secure than CA signed certificates now? I ask this because recent leaks about the NSA spy programs and the secret FISA courts mean that the US government ...
15
votes
1answer
30k views

Can a CSR be created in OpenSSL with SHA2?

Can a CSR be created in OpenSSL with SHA2? If so, what would the command be and what does this tell the CA, if anything? If you could create a CSR using SHA2 would it "tell" the signing CA to use it ...
14
votes
3answers
2k views

Can a wildcard SSL certificate be issued for a second level domain?

Something like *.com or *.net? How about *.edu.au? The RFC 2818 does not say anything about this topic.
14
votes
1answer
4k views

How does OCSP stapling work?

I've been looking into OCSP stapling for HTTPS, which looks pretty interesting. From what I can tell, it's essentially a way of offloading CRLs from the CA to the server, allowing for everything to be ...
14
votes
3answers
252 views

Domain name expiration and TLS

If I purchase a domain name that has expired, do I have any assurance that the previous owner does not have a valid HTTPS certificate for the site? In other words, do CAs check domain name expiration ...
13
votes
1answer
2k views

Renewing Microsoft Certificate Services Root Certificate

We currently have Microsoft Enterprise Certificate Server installed on a domain member machine which issues 1 year certificates to users for authenticating to VPN. We'd like to start issuing web ...
13
votes
4answers
16k views

How are Chrome and Firefox validating SSL Certificates?

How are Chrome and Firefox validating SSL Certificates? Are they requesting data from an SSL certification website, like GeoTrust, to validate the certificate received from the web server?
11
votes
4answers
1k views

What kinds of SSL certificates are usable for encryption?

I know that Verizon SSL certificates cost close to $600. There are couple of cheap alternatives, but I never really understood why Verizon does not offer such certificates. Look for RapidSSL at ...
11
votes
1answer
680 views

Why isn't there a certificate revocation request standard?

Say I am building a Certificate Authority software and I want to automate certificate revocation as much as possible. I know it will not be possible in some cases, like if the building where the ...
11
votes
2answers
3k views

How does DNSSec work? Are there known limitations or issues?

Based on information from this site, DNSSec is needed to protect us from a number of DNS and SSL / TLS hacks, including: DNS spoofing, especially on wifi or shared medium Registrars that abuse their ...
11
votes
4answers
2k views

Multiple CAs signing a single Cert/CSR?

Just saw this suggested on Slashdot So I've seen quite a few people wanting a switch to self-signed certs (who IMO mostly don't understand what making that secure actually involves), and an idea ...
11
votes
1answer
504 views

Is using a CA more secure if I'm self-signing anyway?

We have a web application that we run for clients at their booth on fairs. The communication between clients and the server was done over HTTP until recently. We're currently working on improving ...
11
votes
1answer
150 views

How CA ensures that a certificate request is coming from me?

To establish trusted SSL connection I need to create a certificate request. For example, if I use openSSL I can do it by the following command: openssl req -new -key privkey.pem -out cert.csr ...
11
votes
2answers
1k views

What does having an internal two-tier PKI protect against?

There are a lot of Best Practice documents that recommend having an offline Root CA and an Enterprise Subordinate CA that is signed by the root, for an internal Microsoft AD Certificate Services ...
11
votes
3answers
350 views

What email addresses are treated as trusted?

Windows Live recently suffered a security incident because they didn't realize that email addresses like administrator@live.fi are considered "trusted": some certificate authorities will consider ...
10
votes
2answers
955 views

How are digital certificates compared?

I have read about SSL and TLS; I know how RSA works and why digital certificates are necessary (more or less), but I am curious about how we prevent a fake digital certificate. The operating system ...
10
votes
3answers
4k views

Why is my Positive SSL certificate deemed insecure by Google Chrome? [duplicate]

We run a website over HTTPS with a wildcard certificate from Positive SSL. Today, when I opened Google Chrome (v. 42.0.2311.90 m) and navigated to the site, I noticed a red cross through the https ...
10
votes
4answers
5k views

What Trusted Root Certification Authorities should I trust? [duplicate]

After two recent Slashdot articles (#1 #2) about questionable Root Certificates installed on machines, I decided to take a closer look at what I have installed on my machines. (I use current versions ...
10
votes
1answer
482 views

Why can the validity of an SSL certificate exceed the registration period of a domain?

I can understand why one might desire to purchase a certificate for multiple years but I am left wondering why it appears to be possible to obtain a valid certificate for a domain that may have come ...
10
votes
1answer
316 views

Where does a Hyper-V guest get its entropy when generating a certificate authority key pair?

According to findings by the EFF's SSL observatory, there are "tens of thousands of keys that offer effectively no security due to weak random number generation algorithm." My understanding of that ...
9
votes
5answers
6k views

A standard way to manually add a digital signature to a pdf file?

I've created a few certificates to use myself, but I find myself stumped when it comes to creating a certificate which contains a digital signature. First, how would I go about creating a standard ...
9
votes
1answer
503 views

What are the problems with creating an own CA for intranet?

In the comments to Creating my own CA for an intranet several people strongly advise against creating your own CA for an intranet. Especially: don't do it. Nope. Bad idea. Buy $10 CA signed ...