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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Creating an X.509 certificate with an invalid signature

Creating an X.509 certificate with a valid signature with OpenSSL is pretty well documented all over the Internet. There are instructions on creating certificates that are signed by themselves and ...
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482 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 ...
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PKI solution vendor selection

What would you look for in a (X.509-) PKI solution, and why would you look for that, given the following constraints: Available programming/sw-engineering know how is limited (ie, "OpenSSL with a ...
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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?
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256 views

Why do some certificates specifically identify a corporation and most don't?

Looking at a handful of websites that allow for/require HTTPS, I realized that the certificate for a few of them specifically identifies the owning corporation, but some (most) don't. What's the ...
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What SSL key should I make for IIS: RSA or DH? What bit length is appropriate?

I'm creating an SSL cert for my IIS server and need to know when I should choose the Microsoft RSA SChannel Cryptographic Provider or the Microsoft DH SChannel Cryptographic Provider. Question 1 Why ...
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What issues arise from sharing a SSL certificate's private key?

Scenario: I am hosting a website for a my client, who we'll call S. S owns the domain s.com and I own the servers that actually host the website. S now wants to enable SSL on their website. I have ...
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SSL Certificate revocation check

In the SSL protocol I don't see where the certificate is checked for revocation status. https://developer.mozilla.org/en/Introduction_to_SSL Is the Certificate Revocation and Status Checking not ...
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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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What are the problems with creating an own CA for intranet?

In the comments to Creating my own CA for an intranet several people strongly advise against creating your own CA for an intranet. Especially: don't do it. Nope. Bad idea. Buy $10 CA signed ...
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551 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 ...
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366 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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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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601 views

Should I use a Certificate Revocation List?

I've been trying to provide security to my API. I will issue certificates to my clients to access my API through a TLS channel. So it'll be a SSL-Client Authentication. I'm wondering, should I use ...
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7answers
293 views

Proving running code on a website is unchanged

Can it be proved to the user that the running code behind a website with security related code is the same as published? I'm currently looking at a few new project ideas and one involves secure ...
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3answers
498 views

Are there any smartcard/hardware-tokens for certificate-based authentication which are easily destroyed?

It's all very well to use multi-factor authentication, but supposing you want to 'destroy a factor' so that in an situation where you are likely to be coerced to provide your passphrase, you can ...
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1answer
277 views

How should I store and secure self-signed certificates?

I'm fairly certain I shouldn't commit certificates into source control. Even if the repository is private and only authenticated coworkers (for example) have access to it. That would allow for ...
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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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I see two different sets of certificates for Google websites when I am at work and when I am at home

I see two different sets of certificates for Google websites when I am at work and when I am at home. I mean if I save the certificates (in firefox, click on the "Google.com" block on the left of ...
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Is there any way to get Chrome 27 to trust a self-signed cert? [closed]

I'm running latest gen Chrome (27) and preparing a demo that requires using a self-signed cert to support HTTPS on a local IIS website. The cert has been created with the correct common name for the ...
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4answers
996 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 ...
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4answers
799 views

Why the symmetric key is added to the message?

Yesterday in my class we learnt how to send a message from Alice to Bob with the achieved goals of confidentiality, integrity and authenticity. In order to have a better performance we use a hybrid ...
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2answers
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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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571 views

How are browsers able to find and construct an alternate trusted chain path?

We had a web server that had the wrong SSL certs installed yet the browser was able to find another trusted path to a root and supply the page properly over HTTPS. We also have proprietary software ...
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871 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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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 ...
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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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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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How does adding a random serial number improve a certificates' security?

This article says: "Finding collisions is a tricky process, since it requires you to muck with the bits of the public key embedded in the certificate (see this paper for more details). Also, ...
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259 views

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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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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1answer
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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 ...
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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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Does the SSL encryption strength or validation level 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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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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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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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 ...
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1answer
278 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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1answer
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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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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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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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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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6answers
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Easy explanation of SSL client certificates for a developer

I've been thinking about using client certificates for my web apps, desperately hoping for security-conscious users to put their private key on HSMs so they don't get stolen even if the machine is ...
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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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how to import a private key in windows

Say I have an X.509 cert and a private key that corresponds to it. I can import X.509 certs easily enough into Windows but what about private keys? Is the only way I can do that by converting both ...
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Firebug reports SHA-1 certificate error

For the script at the bottom of this post, Firebug reports the following error: This site makes use of a SHA-1 Certificate; it's recommended you use certificates with signature algorithms that ...
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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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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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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 ...
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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 ...