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

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49
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12answers
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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 ...
60
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 ...
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 ...
62
votes
10answers
13k 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 ...
14
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 ...
74
votes
11answers
19k 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 ...
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, ...
162
votes
7answers
16k views

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 ...
27
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 ...
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 ...
18
votes
4answers
21k 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 ...
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.
8
votes
2answers
573 views

What kind of certificate do I need to be able to sign my own subdomain certificates?

We are making a web-based application that will be installed in intranets as a virtual machine image (we send the user a CD with the virtual machine image, user runs it in a VMWare/VirtualBox/...). ...
137
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 ...
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
2answers
671 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? ...
7
votes
7answers
4k views

Is Spoofing a CA signed certificate possible?

I had never thought about this situation before, I may be completely wrong but I am going to have to clarify it anyway. When a communication starts with a server, during the client handshake, the ...
6
votes
1answer
6k views

SSL Certificate framework 101: How does the browser actually verify the validity of a given server certificate? [duplicate]

Sorry I know this is a complete noob question and at the risk of posting a somewhat duplicate topic. I have a basic understanding of public/private key, hashing, digital signature... I have been ...
17
votes
3answers
864 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 ...
8
votes
5answers
2k views

Understanding SSL certificate signing

I am trying to understand how SSL certificate and signing and the chain of trust works. I know about root CAs and that they are used to sign intermediate CAs that sign the end certificates that are ...
15
votes
9answers
706 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 ...
17
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?
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 ...
9
votes
1answer
265 views

I want trusted SMIME certificates for 3rd parties. Is this a reasonable configuration?

I want to send out SMIME certificates with my emails, and want to deploy the following PKI Root01 (All EKU, All Constrants, No Restrictions) PolicyInt01 (Internal applications, not trusted by 3rd ...
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.
20
votes
3answers
30k 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?
6
votes
3answers
395 views

On-line cryptographically signed date/time?

I’m looking for a source of on-line cryptographically signed date/time. I do not need a full timestamp service, as I am happy with the information « date/time was that », without a link to a ...
5
votes
3answers
5k views

How do I check that I have a direct SSL connection to a website?

I always thought that if I had an SSL connection there would be no MITM attacks. Now it appears that isn't true (see comments in this question Is it okay from a security perspective to read foreign ...
11
votes
1answer
149 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 ...
4
votes
2answers
238 views

Explicitly prohibit an intermediate CA certificate on OpenSSL

How do you explicitly not trust a particular certificate (especially, CA certificate) for OpenSSL? On NSS-based applications, one can install the cert with trustarg p: prohibited (explicitly ...
2
votes
1answer
379 views

Security Certificates - Tools to Generate Security Certificates

I want to create a self-signed certificate that will be installed as a trusted certificate authority. I then want to create another two certificates which are signed using the private key of the ...
1
vote
3answers
329 views

Where can I find all SSL CA certificates

I am working on an SSL implementation project and ofcourse I need to verify the certificate presented by the server. To do that I need CA certificates or at least root CA certificates (correct me I am ...
107
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 ...
23
votes
4answers
8k 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 ...
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 ...
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 ...
16
votes
3answers
2k 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 ...
14
votes
3answers
249 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 ...
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 ...
12
votes
1answer
28k 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 ...
8
votes
1answer
1k views

TLS 39 month certificate limit and Chrome's NET::ERR_CERT_VALIDITY_TOO_LONG error

Late last year the CA/Browser Forum decided to limit the maximum valid term of TLS/SSL certificates issued after 1 April 2015. After this time, as the official guidelines put it.. CAs SHALL NOT ...
5
votes
4answers
3k views

Is it possible to create a self signed certificate authority?

Would it be possible to create a legitimate certificate with the CA bit set? I dont have a usecase associated with this, I'm merely curious. To explain my question : Suppose I sign a public ...
5
votes
1answer
3k views

AIA/CRL locations for Offline Root

I've read the answer to the following "Checklist on building an Offline Root & Intermediate Certificate Authority (CA)" and I have one questions based on the system I am trying building It's an ...
5
votes
1answer
2k views

Can a certificate have multiple chains and multiple self-signed roots?

The following MSFT document has this paragraph: All possible certificate chains are built using locally cached certificates. If none of the certificate chains ends in a self-signed ...
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 ...
11
votes
3answers
3k 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 ...
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 ...
10
votes
1answer
474 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 ...
8
votes
2answers
2k views

Obtaining an S/MIME certificate without disclosing my private key to the TTP

I would like to obtain a trusted S/MIME certificate, but all the certificate authorities I have asked so far generate the keypair on their server, sign the certificate and send me both the private key ...
8
votes
2answers
824 views

security of PKI, Certificates, certificate authorities, forward secrecy

I want to understand how certificates add to the security of information exchange. Suppose i have a encrypted bidirectional connection between Alice and Bob, using a public key/private key pair. As ...