A piece of data used in public key cryptography that contains identifying information (i.e. email address or web address), a hash of a public key, and a digital signature that authenticates the data in the certificate.

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530 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
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2answers
3k views

OCSP and CRLs: Specified in CA or client certificate?

Here's an example PKI setup: * Root CA (offline) * Issuing CA * Client 1 * Client 2 I'd like to specify a CRL distribution point for CRLs generated by Root CA, and an OCSP URL for Issuing ...
9
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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 ...
7
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1answer
6k views

What is a Certification Path in SSL certificate?

I've been trying to learn more about Digital certificates for the past few days and I'm struggling in order to understand how actually this concept is applied in the real world. Anyways, as I visited ...
7
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1answer
1k views

Choosing an SSL certificate provider

Does it make any difference which provider I get my SSL/TLS certificate from? In particular, what are the pros and cons getting an SSL certificate from Verisign vs getting one from Thawte? Which one ...
7
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2answers
5k views

What is an intermediate certificate authority?

What is meant by an "intermediate certificate authority?"
6
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1answer
2k 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? ...
6
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2answers
1k views

What are the real-time applications of long term digital signature with timestamp

I want to know the real time applications that uses digital signatures with timestamps. Specially I am interested to know the applications where we can trust an old signed document which is now ...
5
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2answers
623 views

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 ...
5
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3answers
1k views

P12 - Extract public part (certificate) without knowing the p12 password

I would like to extract the public part of a revoked P12 which doesn't belong to me. I can't open it with KeyStore Explorer because I am prompted for the password, is it possible with OpenSSL ? The ...
3
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1answer
2k views

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 ...
2
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2answers
8k views

OpenSSL, x509: what's the significance of CN (Common Name)?

With regard to these three items Certificate Authorities (CA) Gateway certificates End-point Certificates (client-cert) What is the significance of the Common Name CN with regard to the a VPN? ...
2
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1answer
1k views

What is the difference between `extendedKeyUsage` and an application policy?

In some Microsoft articles like http://technet.microsoft.com/en-us/library/cc731792%28v=ws.10%29.aspx, I find some confusing statements like Application policies are sometimes called extended key ...
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vote
2answers
174 views

Is it Possible to use one commercial SSL Certificate to issue end user certs?

My organization is preparing to purchase some 50 "units" from Symantec, with which we can purchase Verisign SSL certificates of varying authentication levels. Our organization does not have--but ...
1
vote
2answers
6k views

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]: ...
15
votes
2answers
786 views

Why does rfc6797 say “An HSTS Host MUST NOT include the STS header field in HTTP responses over non-secure transport.”

Why does the RFC prohibit the server from sending HSTS to the client over HTTP? I can see that if a HTTP client responds to that unsecure HTTP response it might cause that site to be inaccessible ...
13
votes
3answers
1k views

Trying to understand why signatures in root certs “are not used”?

Taken from here: Don't worry if the root certificate uses SHA1; signatures on roots are not used (and Chrome won't warn about them. Why are the signatures not used? Are not root certificates ...
11
votes
5answers
4k views

Is it safe to send a CSR via email?

I'm new to commercial SSL certificates and would like to know if a CSR that I generate is safe to send via email?
7
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1answer
133 views

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 ...
6
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2answers
110 views

Understanding Digital Certification as as a whole starting from a normal http request

I am trying to understand the difference between digital signature and digital certification and how they work as a whole together on a high level perspective. I hope gurus here can point to me if my ...
6
votes
1answer
817 views

What's keeping a malicious man in the middle server from forging a valid certificate

According to process of authenticating a server certificate: What's keeping a malicious server to fill up a valid server certificate since it knows all the things: Forged Server public key (man ...
6
votes
2answers
376 views

Are any major websites offering ECDSA authentication?

At the time the Cloudflare blog post “ECDSA: The digital signature algorithm of a better internet” was authored, Cloudflare was apparently one of "fewer than fifty" users of ECDSA certificates on the ...
6
votes
4answers
4k 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 ...
5
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5answers
434 views

How can I explain self-signed certificates to users?

I don't trust certificate authorities, so I'm using a self-signed certificate on my server. The server provides both a website as well as other services. Most modern SSL-capable software, upon ...
5
votes
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 ...
5
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1answer
518 views

'Trusted CA Certificates' and 'Trusted remote Certificates'

What is the difference between Trusted CA Certificates and Trusted remote Certificates?
5
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6answers
1k 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 ...
4
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1answer
1k views

How would you know a certificate/private key if you extracted it from RAM? Or would you?

Related to, of course, the heartbleed vulnerability, I've been reading the news about the worst case scenario for this attack being the extraction of the SSL private key, because, of course, this ...
4
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1answer
357 views

Public keys without the certificates

There are two clients and a server. Each client generates an RSA key pair and uploads public key to the server. The server associates the public key with the user identifier that is specified during ...
4
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2answers
294 views

self-signed certs that aren't the final certificates in the path

The X.509 spec makes frequent statements like this: (b) If certificate i is self-issued and it is not the final certificate in the path, skip this step for certificate i. How can you have ...
3
votes
1answer
187 views

Check root certificates and certificate authorities on new PC

First Lenovo was caught shipping Superfish with new PCs, which included a universal self-signed certificate authority, and now Dell has been caught shipping PCs with a similar root certificate. What ...
3
votes
1answer
128 views

How to trust a CA to sign a CRL but not a cert?

In my application, there are many parties that are trusted to revoke a cert (ie by signing a CRL), but are not trusted to sign (new) certs. How do I mark a CA to be trusted only for CRLs, and not for ...
3
votes
2answers
536 views

Why is a CSR hashed?

What are the use cases for defining something other than the default SHA1 hash in a CSR? Is it to protect the digital signature, public/private keys? What is it protecting exactly?
3
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4answers
439 views

Trust among the root-CAs

The system of CAs with the root-CAs and their subordinate CAs are IMHO in principle akin to the system of banks with their main sites and subsidiries. In the case of banks, a customer of a bank ...
3
votes
1answer
208 views

Is it a good idea to generate certificate-specific CRLs? What is this technique called?

Suppose I create 3 certificates with the following CRLs Cert1 http://crl.server.com/batch1/root1.crl Cert2 http://crl.server.com/batch2/root2.crl Cert3 ...
3
votes
1answer
440 views

How can I use certificates to secure my webservices? What is available to javascript?

I have a few web services that are accessed over public wifi connections and I think it would be a good idea to issue certificates to encrypt data, prevent MITM, and invalid impersonation (beyond what ...
3
votes
2answers
206 views

SSL Certificate Signing by a CA

Per my understanding about SSL's, a user has to send his CSR to a CA (Verisign) to get it signed, and Verisign will send the sign X.509 certificate in return. What I don't understand is what, ...
2
votes
2answers
165 views

Using digital certificates in digital signatures

Please could anybody explain to me how certificates are used with digital signatures? I understand difference between certificates and signatures. It is clear. Digital certificates are used to ...
1
vote
1answer
80 views

How to determine which Browser Certs to reenable on a per-case basis?

Considering that there is no way to actually see which certs that I use in my regularly-visited websites, I've decided to disable all certs and re-enable them on a case by case basis. This is for the ...
1
vote
2answers
178 views

Can revoked certificates be “lost” if the base CRL is updated before expiration?

Assumption Suppose I have a CA that issues a base and a Freshest CRL. I also understand the Freshest CRL to be a Delta of revoked certs in the base. I also understand that clients should pull the ...
0
votes
3answers
512 views

In order to trust the digital certificate, does immediate CA cert also needs to be in trust store or root CA cert is enough?

In order to trust the digital certificate, does immediate CA certificate also needs to be in trust store or root CA certificate is enough?
0
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1answer
675 views

How do I constrain Windows Smartcards for AD Authentication so that “anyExtendedKeyUsage” is not implied?

This document describes how there are 3 ways to constrain a SmartCard certificate The Enhanced Key Usage field defines one or more purposes for which the public key may be used. RFC 5280 states ...
-1
votes
2answers
1k views

Generate openSSL certificates from within C code using commands?

This is an openSSL command for generating a private key and a certificate, openssl req -out CSR.csr -new -newkey rsa:2048 -nodes -keyout privateKey.key The question I have is whether there is some ...
10
votes
4answers
665 views

How to stop/detect someone else registering a certificate for my domain

With the proliferation of low-cost automated CAs what can be done to mitigate the attack of someone doing a spear phishing attack to get a login to our webmail system, then using an automated service ...
8
votes
2answers
1k views

X.509 certificate policies question

I asked another question about certificate policy mappings. This is a different issue. This is about Certificate Policies. To quote from the X.509 RFC: In an end entity certificate, these ...
7
votes
2answers
277 views

Should a wildcard ssl certificate be shared with a different organization hosting a subdomain?

We are hosting our own secure site with a wildcard certificate. However, we are working with a marketing company that provides landing pages on subdomains of our domain, on ip addresses supplied by ...
7
votes
2answers
4k views

Obsolete cryptography (SHA1) warning although certificate uses SHA256

I ordered a certificate with SHA256 from Comodo and was wondering why Chrome shows this message: Your connection is encrypted with obsolete cryptography. The connection is encrypted using ...
7
votes
1answer
4k views

Should I regenerate new SSL private key yearly? [duplicate]

Im' renewing my certificate every year. Since I have to make a CSR, should I also renew my key pair at the same time, or is it ok to get a new cert with the same key ? Please supply any security ...
5
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2answers
113 views

Why do so many browsers show sites with revoked certificates?

Everyone seems to agree that it is REALLY important to protect private keys so the encrypted Internet can remain just that (see for example at How do certification authorities store their private root ...
5
votes
3answers
1k views

Digital Signature and Verification?

AFAIK , When Alice wants to write a message to Bob -- she uses Bob's public key and encrypt the message - and then Bob - using his private key - use to decrypt it. So public key is used to decrypt ...