Questions tagged [certificate-authority]

A Certificate Authority is the collection of hardware, software, and people responsible for issuing certificates in a hierarchical PKI. CAs may be public, as in SSL / TLS and government IDs, or private, as in corporate infrastructures. The primary responsibility of a public CA is to verify the identity of an applicant before issuing them a certificate.

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How TLS certificate chain is verified

Assume the verification of a TLS certificate chain. Suppose the chain has certificates A-B-C-D where D is the root certificate and A is signed by B, B by C, C by D. Suppose the intermediate ...
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Are certificate authorities required to obey to the signature algorithm (hashing) specified in the CSR?

I was playing a little bit with signature algorithms, trying to determine which CAs among the ones I use are currently issuing SHA2 certificates. I generated a CSR specifying the SHA256 hash (either ...
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Why would an organization like the DoD prefer to use its own Root Certificate(s)?

While browsing some US military and governmental sites, I noticed their HTTPS connection to rely on DoD Root Certificates. As most of us know, web browsers are pre-loaded with a default set of root ...
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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 ...
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1answer
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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 ...
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How to detect the NSA MITM attack on SSL?

As Bruce Schneider reported here... https://www.schneier.com/blog/archives/2013/09/new_nsa_leak_sh.html ...the NSA reportedly performed a MITM attack on a company in brazil and decrypted their SSL ...
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When you buy a certificate, does the certificate authority have (a copy of) the private key?

I always assumed that the process for getting a (trusted, not self-signed) certificate was more or less like this: You generate a public and private key pair From this key pair you generate a ...
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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 ...
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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 challenge/...
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What happened with Kazakhstan's Root CA MITM policy?

In 2015 there were news that Kazakhstan was going to start intercepting all HTTPS traffic via "man-in-the-middle attack" starting Jan 1, 2016, by requiring kazakhstanis to install their root CA. ...
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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 certificate,...
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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 ...
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Comparison and difference between CAs

While doing some Google searches, I learnt that there are a lot of different Certification Authorities like the Windows role named "Active Directory Certificate Services", the OpenSSL library or the ...
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Why don't browsers check CAA records to help ensure a certificate is valid?

If I understand correctly, Certification Authority Authorization DNS records are used to specify which certificate authorities are allowed to issue certificates for a given domain. If that record ...
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1answer
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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 ...
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Internal SSL Certificates?

As a developer I really like the idea of using OpenSSL to get perfectly good, free, SSL certs. Unfortunately, from all the research/analysis I've done so far, it doesn't look like there is any way to ...
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How does “Let's Encrypt” provide authenticity?

https://en.wikipedia.org/wiki/Let's_Encrypt https://en.wikipedia.org/wiki/Information_security#Authenticity AFAIK with "Let's Encrypt", we could create HTTPS websites with only one command. ...
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Should the bit-strength selection of a child certificate be influenced by the CA or the chain?

All things being equal; suppose I have a CA chain that has 1024 bits of RSA encryption. Does this mean that my selection of a child CA or WebServer certificate gains no benefit from a higher level of ...
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What OID Issuance Policies are appropriate for SmartCard and Browser Certificates?

I'm investigating issuance policies for SMIME and Browser certificates with different levels of assurance. For the purposes of S/MIME and Browser certificates, should I even use an assurance policy? ...
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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 key(...
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Purpose of certificates signed and trusted by CA

Another newbie question but I just don't get the purpose of certificates signed and trusted by CA. We already have public/private keys, hash functions to sign/encrypt messages so why do we need ...
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SSL Certificate Trust Model

I have been looking at the SSL Certificate Trust Model, and there is something that does not make sense. If I am correct, the trust model makes it that if there is a chain of certificates with a ...
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Unrecognized leaf certificate

Every 15 minutes or so I get this message in my system.log Apr 25 22:05:36 Ivans-MacBook-Pro.local apsd[194]: Unrecognized leaf certificate Apr 25 22:20:57 Ivans-MacBook-Pro.local apsd[194]: ...
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What are the risks of a localhost signed cerificate?

In our company we have an internal CA certificate for signing various things including the proxied (MITM'd) HTTPS connections. Suppose we use this CA to sign a key for "localhost" for use in ...
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Should I be concerned that Google no longer trusts specific Symantec root CA cert that is also on my Windows system?

This is related to this other question which refers to Google moving to distrust the "Class 3 Public Primary CA" root certificate operated by Symantec Corporation, across Chrome, Android, and Google ...
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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 ...
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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 ...
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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 ...
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What is an intermediate certificate authority?

What is meant by an "intermediate certificate authority?"
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Certificate authorities for a PKI

Some people think the certificate authorities for a PKI should be the government, but others think certificate authorities should be private entities, such as banks, corporations, or schools. What are ...
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Is cacert.org more harmful than self-signing?

I don't understand the https security model attempted upon me by The OpenBSD Journal (undeadly.org). Instead of using self-signed certificates for https like they did in the past, they for a while ...
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Why firefox shows some connections are not secure?

I am using internet by connecting mobile phone to my laptop using usb. From yesterday,my browser (firefox) shows for all most all website. Why this happen? How can i solve this?
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TLS-RSA vs TLS-ECDHE-RSA vs static DH

I understand there are a lot of articles explaining this subject and, before I post my question, this is my current understanding about it: ECDHE-RSA = The server randomly generates a DH-key pair ...
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Can a website have multiple valid TLS certs looping back to multiple root CAs in case one of them is compromised?

Sometimes, CAs get compromised, like Diginotar or Comodo. In such an incident, anything can happen from individual certs being revoked to the entire tree being scrubbed from the cert store. A company ...
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How will Certificate Transparency be enforced?

The Chrome team has announced that "[they]’ll be moving forward with [their] plan to require Certificate Transparency for all newly issued, publicly trusted certificates starting in April 2018." It's ...
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1answer
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Issuing and managing large numbers of certificates for client authentication

I am developing an Internet of Things product and plan to use client certificate authentication, issuing each "thing" its own certificate on the production line so that it may authenticate with a ...
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Do I really need all these Certificate Authorities in my browser or in my keychain?

There are lots of strange looking Certificate Authorities in my keychain as well as Firefox. I am sure they are legitimate CAs (as they are the same on my Mac and PC and other computers I checked). ...
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Is StartSSL.com a trustworthy site? [closed]

I just got the following email: Dear StartCom customers, This electronic mail message was created by StartCom's Administration Personnel: StartCom, a leading global Certificate ...
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What happens when certificates further up the chain expires before mine? (Equifax/GeoTrust)

I just bought a certificate from RapidSSL. Looking up the chain, I found GeoTrust who is signed by Equifax. Then I realized that the ”Equifax Secure Certificate Authority” is due to expire on 2018-08-...
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1answer
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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 Anyone ...
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How can a domain be impersonated with a fraudulent SSL certificate?

I was reading this article about the fraudulent certificates from Comodo back in 2011. It talks about domain impersonation. I understand that a fake website could be secured with the fraudulent ...
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Browser blacklists & the Symantec-Google Certification Debacle

Background: As explained e.g. on this Google company blog, Google writes that: On September 14, around 19:20 GMT, Symantec’s Thawte-branded CA issued an Extended Validation (EV) pre-certificate ...
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Is it required to have the same Domain Name and Common Name for SSL Certificate?

I have an SSL cert in which CN is "abc.xyz.com". But the url shared to 3rd party organization to access a web app on our server is: "def.stu.com/what-ever". When this arrangement is working for ...
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How to become an internationally recognized certificate authority (CA)?

What's the procedure a certificate authority (CA) must follow to get internationally recognized, like Verisign or GlobalSign?
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What is updated with “Update Root Certificates” enabled? What is the equivalent in Windows 2008R2?

What root certificates are/are not updated when the following checkbox is checked? Additional questions If I manually remove a root certificate, will this service replace that very certificate? What ...
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How practical is a certificate's “basic constraint” property in protecting my HTTPS / SSL session?

Suppose a leaf node creates a certificate for a different domain, acting as a CA. Do most popular frameworks, or SSL chain validation tools verify the constraints? Are there any I should be ...
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What tools exist to help me monitor OCSP certificate validation failures?

The discussion at Why isn't OCSP required by default in browsers? notes that many browsers by default simply ignore failure to check web site TLS certificate revocation status via the Online ...
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“Web of trust” for self-signed SSL certificates?

SSL certificates, generally speaking, use a "chain of trust" model - a trusted certificate authority (CA) gets proof that a company such as Amazon owns amazon.com and issues an SSL certificate. ...
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Google certificate and CAA

I am fiddling around with certificates, trying to harden my own sites. When doing so, I noticed that Google have some weird configuration of their CAA. Looking at their ssllabs results, or using ...
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Use Client Certificate using Self Signed CA while using Web Certificate of a publicly trusted CA

I would like to ask if it is possible to use different CA for the client certificate and the web certificate? For example, I would use Verisign to sign my web certificate while I use my Self Sign ...