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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Why are website certificates secure?

I understand how HTTPS connections work, and I also understand they they require a certificate to know that the secure connection you have is with the right server (and not someone pretending to be ...
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1k views

Why is it a good idea that X.509 digital certificates have an expiry date?

What is the benefit of having certificates expire at some fixed date?
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2answers
334 views

Why is there no Domain CA?

I was asked to deliver a signed SSL certificate for an IIS server for a client. I have previously done this for the same client/domain before, so it start to seem like an unnecessary expense to hold ...
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2k views

Which properties of a X.509 certificate should be critical and which not?

RFC5280's section 4.2 states Each extension in a certificate is designated as either critical or non-critical. A certificate-using system MUST reject the certificate if it encounters ...
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2answers
503 views

How is an HTTPS login secure when pages use HTTP?

When someone go to eBay's website, they use an unencrypted connection between their PC and eBay's server. If they sign in, they are redirected to a secure site identified by its certificate and may ...
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3answers
713 views

Does the SSL encryption strength of a website really matter?

When looking to get an SSL certificate one is presented with a lot of options. For example lets take Network Solutions since they have a nice comparison chart. Immediately there seems to be 4 major ...
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845 views

How do I store Diffie-Hellman parameters in a X.509 certificate?

In there paper Authentication and authenticated key exchange Diffie, van Oorschot and Wiener recommend to insert the DH parameters into the certificate of Alice. As a result an attacker can not change ...
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667 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 ...
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241 views

distributing files to VPN partners

suppose i've created VPN certificates for a certain VPN-RoadWarrior-Client, expressed in the files VPN-RoadWarrior-Client.key and VPN-RoadWarrior-Client.crt*, however VPN-RoadWarrior-Client is ...
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6k views

Encrypting local HTTP traffic using a self-signed certificate

For the past couple of hours I've been trying to create a self-signed certificate which I'd like to use to encrypt HTTP traffic between computers and a server on my home network (because I'm paranoid ...
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1answer
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Moving from a one tier to a two tier Microsoft Certificate Authority hierachy

Right now we have a single Microsoft Enterprise Root CA which issues certificates to our VPN users for two factor authentication. We're planning to extend use of the CA to issue certificates for RDP ...
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3answers
286 views

Would using distinct IP addresses help support browsers with older SSL implementations?

We have a site with two wildcard certificates: *.foo.com and *.bar.foo.com. All of our subdomains resolve to the same IP address. Newer browsers work fine with this, but IE7, for example, does not. ...
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4answers
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How to check if wifi is safe while travelling?

I'm quite a bit of a traveller. So i tend to just stay with my smartphone and sometimes notebook. I'm not a security expert but i would like to check how to know if wifi is safe to use. For example, ...
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What web browsers support OCSP stapling? Are the privacy and performance features the same?

OCSP stapling decreases the load on a PKI infrastructure's OCSP server by attaching a signed OCSP response to the target in a TLS connection. In addition it creates a more secure/private session ...
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2answers
674 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 ...
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5answers
4k 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 ...
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2answers
924 views

How is certificate forgery with cheap CA's prevented?

In order to perform a successful man in the middle attack on HTTPS, one needs to either strip SSL layer and convert it to HTTP completely or needs to have a valid certificate from a CA for the same ...
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1answer
3k 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 ...
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5answers
1k 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 ...
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4answers
885 views

Alternative to “web of trust”

Let's say I have an SMIME platform where I want to easily establish trust across the entire world for a particular purpose, for example for sharing valid financial information. I think that a ...
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2answers
3k views

How to set “Not Before” value to past when creating certificate request

We have lots of embedded TLS clients on the field. TLS Servers must be authenticated. Because long power cuts may reset clock of those devices, we have requirement to use certificates with validity ...
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1answer
5k views

Which key usages are required by each key exchange method?

I'm only really concerned with RSA keys, so the exchange methods are RSA (generate a key, encrypt it, and send it over) and [EC]DHE_RSA (generate an ephemeral [EC]DH key, sign it, and use it for key ...
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1answer
2k views

SSL encryption and SSL certificates

I know for a fact that it's possible for for an SSL\TLS session to go on without an SSL certificate, meaning you pass encrypted data, but you don't have a solid foundation of who you are really ...
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1answer
2k views

Why do X.509 certificates have “Key Usage” attribute?

I can find their values and all details in the RFC, but I cannot find why it was decided to have this attribute in certificates, instead of leaving them to be multipurposes. Is there a reasoning ...
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206 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 ...
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3answers
225 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 ...
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1answer
281 views

How can I verify if a website revoked its old SSL certificate keys? [duplicate]

Through reading from multiple sources and watching Security Now's How the Heartbleeds, I have come to the understanding that the following procedure is recommended to be safe from the Heartbleed ...
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227 views

Which signing key should I use for certifying other peoples public keys: master or subkey?

I have a Master Identity key (which is detached from my daily-use keyring) and both encryption and signing subkeys (all are RSA). I sign documents with the signing subkey: GnuPG selects this key ...
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2answers
1k views

Is “Fingerprint Check” enough to verify HTTPS certificates?

So I'm at place A, see this sign: and I'm writing the fingerprints to a piece of paper (this website is just an example): Ok. Then, I go to place B (other country, etc.) then I check this ...
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1answer
87 views

What considerations should apply for self service Renewing, Revoking, or Unrevoking a certificate?

I need to design a self service portal for renewing, revoking, and unrevoking a certificate and have come up with the following rules*: Renewal Certificates have a short term validity and need to ...
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7answers
4k 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 ...
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4answers
1k views

How to prove Bob has received Alice message

I have read up on Digital signature and it is stated that it provides non-repudation. Assuming Alice signs the message using her private key and sends it to Bob, Bob can use Alice's public key to ...
6
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1answer
668 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 ...
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2answers
3k views

Getting self-signed SSL certificates for all https connections made from some premises

Context: I'm currently working as an expat for my company in a country where the Internet is notably untrustworthy. It made the headlines a few months ago for stealing facebook, twitter and gmail ...
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3answers
245 views

Renew digital certificate

If I have deployed a digital certificate on a webserver and if it needs to be renewed then what steps do I need to follow? Will I need to generate a new longer public key private key pair? Why do ...
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3answers
4k views

Any good free SSL proxy on windows?

I'm looking for SSL proxy capable of dumping requests. I want to test custom browser against SSL-MITM attacks. I'm able to re-route all traffic ongoing from browser to machine with proxy. ...
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5answers
307 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 ...
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3answers
562 views

Personal digital certificate how to verify

A server certificate would have its domain name at its subject field. A personal certificate would have your name as the subject field. How can you be sure that there are no two certificates with the ...
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4answers
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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 ...
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3answers
399 views

Why are CA's signing keys available on the internet

I am not very knowledgeable about CA certificates, but I thought these things mainly said "The public key for bank X is Y, and this is verified by CA Z". Once you've bought this certificate, there is ...
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2answers
2k views

What is the difference between SSL and X.509 Certificates?

I used openssl to create a X.509 certificate but I don't quite understand the relationship between a X.509 and a SSL certificate. Are they the same? Is a SSL certificate just a X.509 certificate that ...
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3answers
1k views

Certificate chain

For my computer to verify the identity of a certain certificate should it have all the certificates up to the root certificate?
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1answer
964 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 ...
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1answer
3k views

Getting a Root CA accepted in systems and browsers

I would like to ask about the procedures for a given CA to get one of its root CAs (SSL issuance CA) to get accepted and installed as a trusted root CA in operating systems and browsers.
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2answers
737 views

VPNs vulnerable to MiTM because ANY certificate goes

I spoke to a sysadmin in a business center today who intended to basically perform a MiTM (as he called it) on every connection in his network because people in his office building are using VPNs and ...
6
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3answers
9k views

Is it possible to use wildcard certificates on multiple devices?

I have a server that I want to use a wildcard cert on. It runs multiple services. I purchase a wildcard cert so that I can protect mail.something.dom, www.something.dom, im.something.dom, ...
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3answers
360 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 ...
6
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2answers
460 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/...). ...
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4answers
1k 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 ...
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3answers
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How and when should I use OpenSSL for IT Security? How do I understand the output?

I'm discovering OpenSSL, and already used it to diagnose a faulty SMTP TLS connection, but I'd like to get a better / full understanding of the tool and how to use it. What resources should I use ...