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 ...

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915 views

Force a subordinate CA cert to be signed to include a the CRL distribution point extension?

How can I attach a crlDistributionPoints parameter when signing a CSR I've generated as follows: openssl req -new -key /root/ca/private/private.key -out /root/public.csr I usually sign with: ...
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7answers
9k views

What is the danger of hosting your SSL certificate yourself?

I have Active Directory Certificate Services on my server, which makes it possible for me to deliver an SSL certificate for the websites hosted on the same server. I know that normally, I need to ...
7
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4answers
1k views

How bad it is to install another company's root certificate to your server?

Our company uses a web server with a couple of web sites on it (private and public, over HTTP and HTTPS, some low risk and some high risk including online payments or other sensitive data for ...
7
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3answers
720 views

Risk in buying an SSL cert from a not well-known party

Let's say I know a guy is selling an SSL cert at a very low price, assume they will generate a real and valid cert for me, since I need to submit my CSR to them and they pass to the CA, are there any ...
7
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2answers
5k views

What is an intermediate certificate authority?

What is meant by an "intermediate certificate authority?"
7
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2answers
883 views

One website - two different SSL certificates: two different CA's

I have seen multiple questions focusing on multiple certificates for a single domain (e.g.: a.com/example and a.com/example_one). However, what stops an individual from purchasing a certificate and ...
7
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4answers
5k views

Can an intermediate CA be trusted like a self-signed root CA?

Is it possible within the limits of the X.509 specification to mark an intermediate CA as trusted for a specific purpose, e.g. to verify a VPN, HTTPS etc. server key, just like it would work with a ...
7
votes
3answers
8k 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 ...
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4answers
1k views

Why are there very expensive and cheap SSL same type certificates? [duplicate]

I am about to launch an online shopping site (currently running http) and I was thinking heavily of moving to SSL which includes a green bar, because this is very important. However, when I first ...
7
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2answers
735 views

How can CloudFlare provide a valid SSL certificate for domains not under its control?

CloudFlare provides a reverse proxy, and it offers SSL support ("flexible", "full", "strict full", and "keyless"). How does CloudFlare manage to get a valid certificate for domains it does not own? ...
7
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4answers
939 views

What Country, State and City should I choose when requesting an SSL certificate?

I am really confused about the country, state and city I should select when submitting an SSL certificate. Should I provide the location of my servers or my current home address?I can always reissue a ...
7
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3answers
502 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 ...
7
votes
1answer
881 views

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 ...
7
votes
2answers
4k views

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 ...
7
votes
4answers
3k views

Does a CA need to have the same type of key as the certificates it is signing? RSA / Elliptic Curve (EC/ECDH/ECDSA)

I am making a CA that I hope to be able to sign RSA and Elliptic Curve-capable (EC) keys with. I was wondering if the best approach was: CA with RSA keys capable of signing RSA and EC CSRs CA with ...
7
votes
4answers
5k views

Clarifying self-signed certificates vs root certificate authority

I hope someone can help me understand some fundamentals on SSL certificates that I've had trouble picking up from docs, Wikipedia, and just about everywhere else on the internet. I'm working on an ...
7
votes
1answer
225 views

Does dnssec protect against malicious registrars?

With the recent conspiracy theories around the registrar MarkMonitor Inc., the question arises, if DNSSEC protects against a registrar going malicious (or being attacked). This is especially ...
7
votes
3answers
2k views

Getting started with SmartCards; what equipment do I need, what do I need to know?

I have an unused SmartCard slot on my laptop and I want to learn how companies take advantage of it. Are all SmartCard slots capable of reading and writing a blank card? Are there compatibility ...
7
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2answers
5k views

How to use a Yubikey NEO (or any OpenPGP card or GnuPG in general) to sign X.509 CSRs?

Since the Yubikey NEO can be used as an OpenPGP card (see here) with three 2048 bit RSA keys, I thought about creating a CA from one of its public keys. Since the private key cannot be extracted ...
7
votes
3answers
298 views

Limiting the root certificate chain

I'm playing around with the idea of running a mini-CA with my (hobby) website, likely only used internally with a few select developers for internal emails, client authentication, staging/development ...
7
votes
1answer
3k views

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? ...
7
votes
1answer
536 views

How does the OpenSSL Alternative chains certificate forgery (CVE-2015-1793) attack work?

The security advisory for the issue can be found here: https://www.openssl.org/news/secadv_20150709.txt OpenSSL Security Advisory [9 Jul 2015] Alternative chains certificate forgery ...
7
votes
2answers
1k views

Where are the anonymous/private domain validation SSL certs?

I have yet to find a CA that doesn't require personal information for DV certificates. Is this because all of the major browsers and operating systems have a policy to reject CAs that don't require ...
6
votes
3answers
406 views

Are SSL certificates from a CA necessary for secure communication?

Am I right in thinking that SSL certificates from a CA are purely for identification purposes and serve no purpose in the actual encryption of data? In other words if I were to create a self signed ...
6
votes
2answers
858 views

How does an attack on a digital signature work?

In our IT Security class we have been told that you need CA's to prevent attacks on a digital signature. Sadly, our docent didn't elaborate how such attack would be performed - I can only guess that ...
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4answers
4k 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 ...
6
votes
3answers
1k views

What if someone steals a Certificate authority's private key? [duplicate]

What if someone could steal a Certificate authority's private key? I know this will (probably) never happen, but what would happen to the certificates that were already signed with this private key? ...
6
votes
5answers
413 views

Why are private certificates not trusted?

When we go to websites that have generated certificates themselves you see this red screen that says do not go there!: However when it is trusted by some companies it's all good. So I have a couple ...
6
votes
3answers
3k views

What part of TLS specifies how to verify a certificate chain

I have sometimes run into a situation where I see a root CA certificate which is set to expire sooner than the intermediate CA certificate. My question is - if you were interested in keeping your ...
6
votes
3answers
193 views

Guarding against rogue certificates

There has been a lot of news recently about certificates being falsely issued (due to the issuing authority having poor system security!). Apparently the targeted users were mostly Iranians, but it's ...
6
votes
2answers
526 views

How can we revoke all ssl certificates issued for our domain?

After having the hostmaster@domain.com email compromised, we found that someone issued a Domain Validated SSL certificate for our domain. Now we want to have all such certificates revoked. Is there ...
6
votes
3answers
5k views

Why are Certificate Revocation List periodically renewed?

While studying a security course I have been asked this very question: Why are CRL periodically renewed, even if there are no new revoked certificates to add to the list? Honestly I can't find the ...
6
votes
2answers
235 views

Why do Symantec not believe their customers will be affected by Google distrusting this root certificate?

So Google will be moving to distrust the “Class 3 Public Primary CA” root certificate operated by Symantec Corporation, across Chrome, Android, and Google products, because it is no longer going to ...
6
votes
2answers
6k views

Is an AIA or CRL useful / required at the Root CA if that Root is used to cross certify another PKI?

Suppose I have several independent PKIs that are used Two internal PKIs: One with SHA1 support the other with Suite B algorithms. A partner who I trust and have a policy map with. Since both my ...
6
votes
1answer
3k 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 ...
6
votes
1answer
11k views

Should the thumbprint be SHA2 in addition to the Signature Hash Algorithm?

I'm looking at a Windows PKI and see that the Thumbprint is SHA1, while the Signature is SHA2 (SHA256). Is this an acceptable configuration? Should I recommend that the client update to SHA2 for a ...
6
votes
1answer
5k views

Root certificate key usage (non-self-signed end entity)

This discussion does not include self-signed end entity certificates for hosts like web servers and mail servers. OpenSSL's default configuration for a CA certificate has the following keyUsage: ...
6
votes
2answers
1k views

Root SSL certificates and browser support

I have given three certs to be install on nginx AddTrustExternalCARoot.crt PositiveSSLCA2.crt www_example_com.crt So I concat them into a chained cert cat www_example_com.crt PositiveSSLCA2.crt ...
6
votes
3answers
1k views

Why are SSL certificates valid only from a certain date?

Each SSL certificate is valid starting from a specific date and up to the expiration date. What's the point in that "valid from" date? Why do we want a certificate to only be valid after a specific ...
6
votes
1answer
813 views

For a desktop application, why use an SSL certificate from a trusted authority?

When a web browser connects to a server and downloads an SSL certificate, a third-party trusted authority ensures that the client is talking to the host that it's looking for. If the host uses a ...
6
votes
2answers
151 views

What is the purpose of Intermediate Certification Authorities store in Windows?

Suppose I have CA1 root certificate and two intermediate CA2 and CA3 certificates issued by CA1. Would it pose any security issue if all of the intermediate certificates were installed in the root ...
6
votes
2answers
88 views

Issuing certificates to two departments from same ROOT CA so one does not trust the other

Scenario: We have two departments within IT; Say Department-OLD and Department-NEW. A single internal PKI environment exists and a root CA (singular) is trusted by All endpoints. Problem: ...
6
votes
1answer
933 views

Browsers silently adding trusted root certificates in Windows

When accessing https://internetbanking.caixa.gov.br (site of a well known bank in Brazil), the server returns a certificate signed by "Autoridade Certificadora Raiz Brasileira" (Brazilian Root ...
6
votes
1answer
65 views

Why does the issuance speed of a CA depend on the number of certs they have already issued?

I have seen proprietary testing results of pummelling a CA for a long time and measuring its throughput (certs issued / second). It was found that CAs become slower to issue new certificates as the ...
6
votes
1answer
112 views

S/MIME certificates and “information leakage”

I'm considering getting an S/MIME certificate that verifies my name and email address. I've been trying to ascertain what information "leaks" if I do. The Wikipedia page on S/MIME says: Depending ...
6
votes
3answers
253 views

what do you do when an ssl certificate expires and your app uses ssl pinning?

I originally posted this question on StackOverflow, but reposted here due to lack of responses. I am trying to decide if it's a good idea to do ssl pinning in my iOS game that uses a server to ...
5
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6answers
2k views

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 ...
5
votes
3answers
816 views

Certificate Transparency

From what I read here, if the intermediate CA has been compromised, a fake cert can be issued and the privacy of the end-users could be compromised as well. In order to remediate this situation, ...
5
votes
3answers
1k views

Why do we allow SSL certificates to be replaced before their expiry date, without revokation of others?

Imagine a situation where a rogue CA creates a certificate for your site. Since the user's browser trusts the CA, it will accept the certificate without any fuss. However, the site's real certificate ...
5
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1answer
1k views

Is possible that a TLS server send more than one certificate to the client for the same site?

What I'm trying to archive is enable ECDSA and DSS ciphers in my site, but at the same time not depend just of self signed certificates, so I could sent to my client more than one certificate and them ...