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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15k views

Reset Windows trusted certificates store to its default

Over the time I have installed several additional trusted CA certificates to Windows trust store, sometimes because an app pushed me to do so, some other times for development and testing. Is there ...
5
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1answer
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Chrome is telling me I am receiving a forged certificate for Gmail, is someone trying to hack me?

I went to log on to https://mail.google.com this morning and I got the following error. Is someone trying to attack me or is this just a bug? I'm on a WPA2 encrypted wireless connection using Chrome ...
107
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6answers
18k views

I can't access websites that use HTTPS, instead getting the message “your connection is not private”!

I found myself suddenly unable to access websites that use HTTPS, so I contacted my service provider, and they asked me to install a certificate in the Trusted Root Certificate Authorities store. But ...
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5answers
5k views

Are self-signed certificates actually more secure than CA signed certificates now?

Are self-signed certificates actually more secure than CA signed certificates now? I ask this because recent leaks about the NSA spy programs and the secret FISA courts mean that the US government ...
20
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2answers
28k views

What's the difference between X.509 and PKCS#7 Certificate?

Am I correct calling file with .p7b file extension saved as 'Cryptographic Message Syntax Standard - PKCS#7 Certificates (.P7B)' in Windows - a 'PKCS#7 certificate'? Or is it better called 'X.509 ...
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5answers
5k views

Does HTTPS Everywhere defend me against sslsniff-like attacks?

http://www.thoughtcrime.org/software/sslsniff/ If I have a domain on my HTTPS Everywhere list, so that theoretically it could be only visited via an HTTPS connection in my Firefox, then could an ...
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4answers
2k views

Can any CA sign any domain?

Can any CA sign any cert for any domain? If the answer is yes, what prevents having two different CAs creating a valid cert for the same domain? Does that mean that the whole TLS security has the ...
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8answers
6k views

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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4answers
31k views

SSL Client Certificate authentication

Is it possible to make a program which uses client certificate authentication with only public and private key (I have not generated any certificate, I have only public and private key). Simply, I ...
21
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3answers
9k views

Is SHA1 weak for SSL?

I noticed that today after I scanned a site on the Qualys SSL Labs site that SSL ciphersuites which use SHA1 are now highlighted as being "Weak". It seems this has just happened; I scan sites pretty ...
8
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1answer
3k views

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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3answers
4k views

Do client certificates provide protection against MITM?

I'm looking for a way to protect clients from a MITM attack without using a VPN, and ToR. My thought is that client certificates might do the job, but I'm not entirely sure since not too much server ...
28
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3answers
2k views

Does any technology prevent a CA unilaterally revoking a certificate?

As far as I can tell, a CA is in a position to unilaterally revoke a certificate via the standard mechanisms (CRL, OCSP). In an increasingly TLS world, what current technology stops a CA shutting ...
28
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4answers
41k views

Expired SSL Certificate Implications

What are the security implications of an expired SSL certificate? For example if an SSL certificate from a trusted CA has expired will the communication channel continue to remain secure?
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2answers
2k views

SSL fingerprint inconsistency: what does it mean?

I apologize if this is not the best place to ask my question on the stackexchange network, I couldn't figure out where to get enough attention and be relevant. Facebook provides a SSL host, it can be ...
15
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1answer
14k 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 ...
12
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5answers
2k views

Why are certificates limited in time?

If a certificate has a limited duration of, say 5 years, but it gets somehow compromised after 2 years, waiting the 3 remaining years for it to get invalid is not a real solution to the breach problem....
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2answers
19k views

OpenSSL generate different types of self signed certificate

Does anyone know how to use OpenSSL to generate certificates for the following public key types: DSA - For DHE_DSS key exchange. Diffie-Hellman - For DH_DSS and DH_RSA key exchange. ECDH - For ...
13
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1answer
826 views

Kaspersky Antivirus “secure connection scan” as broken as Superfish?

I've read a lot about Superfish (and similar ad-ware) lately and I basically understand the vulnerability to MITM attacks. But I'm actually wondering if the "secure connection scan" by Kaspersky ...
12
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5answers
2k views

Why is this certificate valid for so many domains?

If you look at the (invalid) certificate for https://i.imgur.com/ it says only valid for the following names: The certificate is only valid for the following names and then a list of about 100 names. ...
7
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3answers
6k views

What does it mean for a digital certificate to be “signed”?

When someone says that a particular digital certificate (like an SSL cert) has been "signed with a key", what does that imply? Does that mean the certificate simply includes a key that should be used ...
15
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2answers
558 views

How much of a problem is it that Windows “hides” some of the trusted root CA certs?

Based on information on this page, Windows actually trusts many more root CA certificates than what are displayed when a user launches certmgr.msc and navigates to Trusted Root Certification ...
10
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3answers
5k views

How does an SSL server prove its identity?

This document says that a challenge response authentication proves the servers identity. But is a man in the middle attack still possible if the client does not verify domain name ? Please help me ...
13
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3answers
8k views

Why is my Positive SSL certificate deemed insecure by Google Chrome? [duplicate]

We run a website over HTTPS with a wildcard certificate from Positive SSL. Today, when I opened Google Chrome (v. 42.0.2311.90 m) and navigated to the site, I noticed a red cross through the https ...
12
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4answers
2k views

Why isn't OCSP required by default in browsers?

According to the following screenshot, taken from firefox-3.6.17-1.fc14.i686, Firefox has an option to fail closed when unable to connect to OCSP servers. Can someone please explain why this isn't ...
9
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4answers
4k views

HTTPS self signed certficiate for personal website

I want to make my Synology NAS accessible over the internet. When I create my own certificate and import this on all my devices (PC, Laptop, Smartphone, Tablet, etc.) is this as secure as buying a ...
6
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2answers
214 views

Using a verified certificate to sign others

This relates to PKI and certificates generally but websites more specifically. Could you get a verified certificate from a CA that is signed and fine for use, and then use it to sign your own ...
5
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1answer
3k views

google certificates correct CA [closed]

I view certificates of https://www.google.com.ua/ So I thought, when requesting via cURL, if I point by CURLOPT_CAINFO to those certificates (GeoTrust Global CA and Google Internet Authority G2 in ...
5
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1answer
5k views

Which extensions to use for a S/MIME certificate?

Analogously to the SSL server certificate question, which extensions should I use for S/MIME, and should the CA be restricted somehow as well? (I'm using openssl, which at the moment creates CA and ...
0
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1answer
335 views

Secure way to pass client certificate to the client2

Our product is comprised of two servers. We would like to authenticate one server to the main server by means of client certificate. I assume that we should ask the customers (who purchase the product)...
16
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2answers
827 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 ...
7
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4answers
2k 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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2answers
2k views

Adding custom data in X.509 certificate

I am using SSL with client authentication. I need to send some extra data while sending the client certificate? Can I send it in the certificate? Can I use the extension fields in certificate for that ...
6
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4answers
5k views

Man-in-the-middle Blue Coat proxy SSL or what?

I have just discovered that my workplace has enabled some new features in the Blue Coat network proxy. It seems like all HTTPS certificates in Chrome on Windows are being issued by this internal ...
5
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3answers
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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2answers
548 views

Signing my certificate by using my smart card and eID card?

In Belgium we have electronic identity cards (eID) issued by our government. They can be read by a smart card reader. On the card are two certificates, one for signing and one for authentication. I ...
3
votes
3answers
716 views

Where can I find all SSL CA certificates

I am working on an SSL implementation project and ofcourse I need to verify the certificate presented by the server. To do that I need CA certificates or at least root CA certificates (correct me I am ...
3
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1answer
3k views

What are the Netscape Cert Type attributes? Why/when are they needed?

What are the Netscape Cert Type attributes in a X.509 Certificate and how are they different with the X509v3 extensions? Example: There is the Client/Server Extended Key Usage (X.509) but there is ...
2
votes
1answer
78 views

Is it possible to issue a certificate with different attributes than in .csr?

Is it possible to issue a certificate with different attributes than in certificate siging request? I have a keypair and I generated a cert. request with extra attributes. Can the CA/RA or anybody ...
2
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1answer
6k views

Creating Client Certificates

Consider an application where client certificates are to be used for authentication. The application web server requires SSL and client certificates for all users. In this case, it's IIS 7. I've used ...
1
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1answer
813 views

How do I convert a GPG certificate to a CRT certificate that can be imported into Windows Certificate Manager?

I have a GPG certificate from someone used for email -----BEGIN PGP PUBLIC KEY BLOCK----- Version: GnuPG/MacGPG2 v2.0.14 (Darwin) I would like to import that into Windows Certificate Manager So ...
14
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4answers
3k 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?
7
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3answers
16k views

What does these warnings mean on an SSL connection by firefox (only)

I am connecting to a secure site and firefox mentions about identity: Owner: This website does not supply ownership information Verified by: Not specified Technical Details: Connection ...
7
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2answers
6k 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 ...
5
votes
1answer
296 views

What issues might exist with TLS-OBC's emulation of Browser Certificates?

TLS-OBC is an RFC proposal that increases SSL/TLS security by using certificates on both ends of the TLS connection. What's special here is that the client is permitted to dynamically create a local, ...
5
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3answers
2k 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 ...
4
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3answers
1k views

How are possible uses for X.509 (SSL) certificates denoted?

X.509 certificates can be used for servers, clients, email, code signing and more applications. http://twitpic.com/6gdxaq indicates that a certificate can have different of these 'capabilities' on it -...
4
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3answers
999 views

Steps to find out whether a SSL certificate is trustworthy

For doing business with a company I have to browse to https://www.prioenergie.de/nc/mein-prioenergie.html (German website). Firefox says the certificate is invalid, because it is not signed by a ...
3
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2answers
486 views

Can I buy a signing-valid certificate for internal use?

So now that I have to implement "secure transport" as defined by The Direct Project (not to mention reinventing a bunch of wheels, but that's another story for SO), I find myself staring down the ...
2
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1answer
524 views

Security Certificates - Tools to Generate Security Certificates

I want to create a self-signed certificate that will be installed as a trusted certificate authority. I then want to create another two certificates which are signed using the private key of the self-...