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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13
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2answers
18k views

Advantages of client certificates for client authentication?

I'm no security expert, so please just ask in a comment if I haven't made my question clear enough for an answer. The Scenario We have a server running WCF services, and a number of clients ...
13
votes
1answer
9k views

What is the actual value of a certificate fingerprint?

In a x509 digital certificate there is a "certificate fingerprint" section. It contains md5, sha1 and sha256. How are these obtained, and during the SSL connection, how are these values checked for?
6
votes
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 ...
1
vote
2answers
185 views

X509 mutual authentication: is there a security flaw?

On the client side, my application accepts the server's certificate in case of the client certificate being signed by this server cert. Is this correct or may it be dangerous? Is it better to ask a ...
2
votes
3answers
9k 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 ...
0
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1answer
204 views

Authentication methods without trusting 3rd parties unless explicitly indicated

The plan is to have a situation in which no third parties have to be trusted unless you explicitly indicate so. For example CA's are only used when the contact explicitly added the CA as a trusted ...
0
votes
1answer
706 views

URIs in the subjAltName X.509 extension

The subjAltTag extension for X.509 certificates can take in domain names, email addresses, URIs, etc. I was playing around with an X.509 whose subjAltTag had just a URI in it doesn't seem to work. ...
1
vote
1answer
119 views

Viable way to authenticate certificate without a web of trust?

For SSL certificates we have a web-of-trust principle. If we are allowed to make alterations to the certificate format, are there viable ways to automatically or semi-automatically authenticate the ...
6
votes
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 ...
3
votes
1answer
551 views

exponent value in certificates

I have seen that in gmail, there are 3 certificates in hierarchy. I noticed that all the certificates have the same exponent(65537 with 24bits). Why is the exponent value same for all certificates and ...
48
votes
4answers
13k views

Are all SSL Certificates equal?

After running a few tests from Qualsys' SSL Labs tool, I saw that there were quite significant rating differences between a GoDaddy and VeriSign certificate that I have tested against. Are all SSL ...
1
vote
1answer
909 views

How to generate self-signed certificate for S/MIME with usage 'signing' only, like DOD uses

I'm testing a feature to support S/MIME mail signing and encryption. As far as I know US DOD has quite strict standard on these certificates. So that DoD uses separate authentication, signing, and ...
4
votes
2answers
941 views

Is DIGEST-MD5 secure if done over HTTPS?

If the DIGEST-MD5 negotiation is done over an HTTPS connection instead of HTTP, does that prevent this list of disadvantages from Wikipedia?: Digest access authentication is intended as a security ...
11
votes
3answers
2k views

Difference between Certificate Authorities

I've been wondering for a long time about is. There are many certificate authorities having different types of certificates. But even certificates of the same security level cost a lot more with one ...
4
votes
1answer
888 views

How secure is TOTP key on phones?

Our company is considering several options in moving to MFA with software OATH TOTP or yubikey OATH OTP. In regards to where the secret is stored, I'm aware that a yubikey or similar hardware device ...
1
vote
1answer
108 views

valid intermediate certs not in browser

Say an X.509 cert is signed by an intermediate cert that's not in your browser. Maybe the root certificate is but not the intermediate cert. At that point it seems like a valid certification path ...
7
votes
4answers
3k views

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 ...
5
votes
1answer
215 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, ...
1
vote
2answers
173 views

SSL/TLS Certificate Authority supply policy

I would like to ask for recommendations regarding the following issue: As a company with a number of customers worldwide we supply our product to many different sites. We need to shape our policy ...
3
votes
2answers
204 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 ...
8
votes
2answers
608 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 ...
2
votes
1answer
522 views

X.509 certificate policy mapping question

So I'm a little confused how X.509 certificate policy mappings work. So let's say the following depicts my cert chain: root CA ---> intermediary CA ---> client cert Would the root CA have a ...
3
votes
2answers
1k views

Secure communication between C# client and Java server, using certificates

I want to secure communication between simple C# WPF client and Java server. Now i have already implemented raw sockets communication, and my security is based on: server send RSA public key to ...
0
votes
2answers
959 views

Issuing browser certificates to Chrome and Firefox with Microsoft CA

Most companies use IE with an ActiveX control to create a CSR and submit it to the CA for approval. Since many browsers either block or don't support ActiveX controls, how can I enroll them using a ...
4
votes
2answers
950 views

How long shall a certificate be valid?

See title. Are there any sources where there are recommended validity times of certificates (based on length, algo, etc)? I'm particularly interested in validity of RSA certificates...
14
votes
2answers
1k 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 ...
2
votes
1answer
336 views

Does iOS use built-in certificates to authenticate peers when using ipsec VPNs?

Suppose I am setting up an IPsec VPN for Apple iOS clients with the requirement that the iOS clients need to know that the server is legitimate and vice-versa. I create a root CA and issue a ...
0
votes
1answer
286 views

id-ce-cRLDistributionPoints ASN.1 / DER encoding question

I have a file - test.pem - with the following contents: -----BEGIN CERTIFICATE----- MBIwEKAOoAwwCqMIMAZhBEFCQ0Q= -----END CERTIFICATE----- openssl asn1parse -inform PEM -in test.pem -i returns the ...
2
votes
1answer
518 views

question about implicitly tags in ASN.1

From the X.509 RFC, in the "Implicitly Tagged Module" section: CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint DistributionPoint ::= SEQUENCE { distributionPoint [0] ...
2
votes
1answer
2k views

My S/MIME certificate (created with OpenSSL) does not match my email address

I created a certificate with OpenSSL and following commands: openssl req -x509 -nodes -days 365 -subj '/C=DE/ST=state/L=city/CN=hostname' -newkey rsa:1024 -keyout mycert.pem -out mycert.pem ...
3
votes
2answers
159 views

Teaching security concepts

I think it would be nice to teach security concepts by giving practical examples. I am looking for some practical cases for x509 certificates, kerberos and SET. How could I know an ecommerse site ...
6
votes
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.
2
votes
1answer
451 views

Does client certificate authentication demand more server-side entropy?

We have a secure web service running Apache that requires client certificates for access. This service has a problem with running out of entropy. We have several other sites that use TLS that get ...
2
votes
1answer
117 views

CSR generation origin?

Platform: Windows 7 x64 Development: .NET 4 Web Server: HttpListener (IIS not installed, will not be installed :) ) Can Machine A generate a Certificate Signing Request for Machine B and have the ...
2
votes
3answers
194 views

What is the worse that could happen if a government wanted to interfere with a CA?

In our time of SOPA, PIPA and ACTA, I was wondering what could happen if a government wanted to remove the certificate of a website ? CA are companies, so they would have to obey to instructions from ...
4
votes
1answer
843 views

X.509 algorithm identifier parameters vs. extension values

From the X.509 specs: AlgorithmIdentifier ::= SEQUENCE { algorithm OBJECT IDENTIFIER, parameters ANY DEFINED BY algorithm OPTIONAL } ...
3
votes
1answer
1k views

Why doesn't asn1parse parse all DER encoding strings?

I have a file - crl.txt - that contains the following: MDYwNKAyoDCGLmh0dHA6Ly93d3cyLnB1YmxpYy10cnVzdC5jb20vY3JsL2N0L2N0cm9vdC5jcmw= It's from one of the extensions in a particular X.509 cert. Why ...
6
votes
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 ...
3
votes
1answer
536 views

Apple Developer Account Hacked?

I just did a fresh install of Snow Leopard on a newly-formatted hard drive. Logged into the iPhone Developer Page with Google Chrome (latest build) here: ...
7
votes
3answers
285 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. ...
33
votes
4answers
25k views

What certificates are needed for multi-level subdomains?

I'm working on a web site with a several levels of subdomains. I need to secure all of them with SSL, and I'm trying to determine the correct certificate strategy. Here's what I need to secure: ...
3
votes
1answer
1k views

parsing the id-ce-keyUsage extension in X.509 certs

I'm trying to decode an X.509 certificate and have a question regarding the decoding of the extensions. In particular, the octet string corresponding to id-ce-keyUsage (OID 2.5.29.15) is as follows: ...
6
votes
2answers
2k 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 ...
11
votes
5answers
4k 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 ...
5
votes
4answers
364 views

What fields in a suspicious certificate should I look at?

Looking at a certificate for a web-site (in Windows/Google Chrome) I see it lists the following fields Version Serial number Signature algorithm Issuer Valid from Valid to Subject Public Key Basic ...
7
votes
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 ...
5
votes
1answer
18k views

How to use OpenSSL generated keys in Java?

I have my pair of Public and Private keys and my certificate. Those where created in OpenSSL (why? because I was asked to do it in OpenSSL). Now I want to use those things to make a Java app that ...
4
votes
3answers
6k views

What data should I validate when validating X.509 certificates using Java?

Well I began with PKI a year ago with RFID system at school. Now I'm asked to implement this in my job. I understand most part of the idea. The doubt is about the certificate validation. I know it ...
4
votes
2answers
702 views

Is there any research on which SSL certificate authority has the best browser compatibility

We're about to release a service that requires website owners to embed our javascript code on their site which will then serve the script from our server similar to Google Analytics. (yes I'm aware of ...
6
votes
3answers
356 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 ...