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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4answers
847 views

Clients trust my custom CA

I'm sorry if this is a dumb question. I'm new to all this. I have a large number of users. I need to be able to generate SSL certs for various internal domain names. All of these certs need to be ...
3
votes
2answers
456 views

Mitigations for Windows clients that don't support OCSP Nonces

Windows 7 clients (and older) don't support NONCES, a key feature used in securing the revocation check. Without a NONCE a MITM could replay a previously signed response and alter the validation of ...
3
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1answer
441 views

Is the Netscape SMIME extension still required in a certificate?

Every Windows 7 host has a Trusted Root certificate from Entrust that has the "Netscape Cert Type" extension (see image) I'm comparing inter-operable S/MIME extensions and see a pretty diverse set ...
8
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1answer
2k 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, ...
5
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1answer
10k views

What is updated with “Update Root Certificates” enabled? What is the equivalent in Windows 2008R2?

What root certificates are/are not updated when the following checkbox is checked? Additional questions If I manually remove a root certificate, will this service replace that very certificate? ...
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2answers
231 views

Using digital signatures to identify users

Consider the following requirement: Bob should be able to verify that a payment request came from Alice. The above is in simple terms the basic idea, however, in reality Alice would be user A of ...
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3answers
685 views

Is it possible to use same certificate on several machines by exporting it?

My bank proposes certificate. They say I will be able to use it only on one computer. I don't understand: can't I use same certificate on several machines by exporting and reimporting it ?
1
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1answer
362 views

What makes a secure smartcard secure? Is contactless/RFID better?

In short what security features exist that I should look for in a smart card? What physical features exist, which are important? It appears smart cards may exhibit different levels of wear and ...
0
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1answer
485 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 ...
16
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1answer
93k views

How do I clear cached credentials from my Windows Profile?

Windows seems to be saving my credentials for a variety of applications (terminal servers, etc) and I'd like to purge this data. How can I backup and purge this data?
2
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2answers
107 views

Using External Certificates on a network that doesn't permit outbound HTTP/S access

Some highly secure networks and DMZs prevent all communication to outside hosts. This can cause issues with validating externally signed data I can guess that issues with signature validation occur ...
2
votes
1answer
3k views

Clearing IE temp files don't erase CRL history. How can this be purged?

Even after I purge all my Internet temporary files, I still see information when I type certutil -urlcache How do I purge this information?
2
votes
3answers
1k views

What is the most secure way to do OCSP signing without creating validation loops?

I'd like to enable the most secure OCSP validation that Windows 2008 SP1 and newer support. Based on the following information, am I required to implement id-pkix-ocsp-nocheck on my OCSP ...
2
votes
1answer
955 views

What are attribute certificates? Why would someone partition a certificate by reason codes?

In "How Certificate Revocation Works" a brief mention of Attribute Certificate and Reason Code partition is made: If validated by a client that supports partitioned and indirect CRLs, the IDP ...
4
votes
1answer
2k views

Can a certificate have multiple chains and multiple self-signed roots?

The following MSFT document has this paragraph: All possible certificate chains are built using locally cached certificates. If none of the certificate chains ends in a self-signed ...
1
vote
1answer
3k views

What are the OIDs (KU and EKU) necessary for Smart Card Authentication in Windows?

MSFT smart card authentication is listed in PKINIT RFC 4556 however I don't see any OIDs listed. Based on this and this KB article the EKU section of the certificate should contain "Client ...
11
votes
3answers
9k views

Checklist on building an Offline Root & Intermediate Certificate Authority (CA)

Microsoft allows a CA to use Cryptography Next Generation (CNG) and advises of incompatibility issues for clients that do not support this suite. Here is an image of the default cryptography settings ...
2
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3answers
178 views

Whether certificates can be used for regulating access

I am thinking of a mechanism where I need to authenticate the client and control the access. I am thinking of using SSL for this purpose. I want to know whether using SSL solves my purpose. My ...
2
votes
2answers
357 views

Trust and signing: full public key or thumbprint?

Imagine a B2B service where two parties need to set up a two-way trust relationship: Alice will only accept requests from Bob, and Bob wants to know his requests are only going to Alice. When ...
1
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1answer
506 views

Best Practices for Storing Digital Certificate

I'm building an application where certain sensitive files need to be digitally signed before being stored in the file system using ASN.1 encoding, so they can be verified against a digital certificate ...
2
votes
2answers
1k views

How to use 'key material' so that multiple people can access protected files?

I'm not sure if this is the right SE to ask this question, but it seems more I have a database of files that needs to be encrypted such that multiple people with different passwords/logins to this ...
3
votes
1answer
129 views

Spurious SSL Certificates when accessing sites through enterprise network

I've noticed recently when I log on to sites like Hotmail that IE has been telling me there is something wrong with my SSL certs. When I examine the certs, the Issuer appears as "Blue Coat" from ...
3
votes
4answers
5k views

Two-factor authentication w/certificate and username & password?

Example scenario: ActiveSync Authentication method: certificate-based authentication AND Active Directory domain username-password Encrypted on device: public & private key AD username ...
8
votes
4answers
2k 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?
5
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3answers
4k views

How do I check that I have a direct SSL connection to a website?

I always thought that if I had an SSL connection there would be no MITM attacks. Now it appears that isn't true (see comments in this question Is it okay from a security perspective to read foreign ...
7
votes
1answer
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 ...
14
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2answers
19k 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 ...
14
votes
1answer
10k 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?
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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 ...
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2answers
200 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
10k 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
votes
1answer
209 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
743 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
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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
580 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 ...
49
votes
4answers
14k 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
928 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
985 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
905 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
109 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
222 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, ...
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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
211 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
650 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
548 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
989 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 ...