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.

learn more… | top users | synonyms

1
vote
3answers
645 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
vote
1answer
357 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 ...
4
votes
1answer
1k 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 ...
2
votes
2answers
104 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
915 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 ...
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?
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 ...
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?
2
votes
2answers
344 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
vote
1answer
490 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
127 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 ...
5
votes
3answers
3k 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 ...
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 ...
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 ...
0
votes
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 ...
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 ...
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. ...
3
votes
1answer
550 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 ...
0
votes
2answers
957 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 ...
1
vote
1answer
908 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 ...
4
votes
1answer
887 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 ...
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 ...
5
votes
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. ...
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 ...
3
votes
4answers
3k views

I had SSL certificate on my site but still it has been hacked…how to prevent this from happening?

I used SSL certificate on my site but still it has been hacked. How do I prevent this from happening? Do SSL certificate come with a waranty which would compensate me because my site was hacked?
17
votes
2answers
790 views

Encryption and the “security time decay” of prior encrypted data

This question is on the assumption that any data once encrypted, may (eventually) be decrypted through Brute force (compute power/time) Exploits in the cryptography used Theft of private keys ...
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 ...
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
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 ...
2
votes
1answer
450 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 ...
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
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 ...
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. ...
8
votes
4answers
14k views

Recommendations for a Certificate Management tool for Linux [closed]

A client is looking to roll out OpenVPN to all its mobile employees and will use certificates on both the server and all clients. This creates a new challenge to manage all these certificates and ...
4
votes
1answer
842 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
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: ...
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 ...
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 ...
8
votes
1answer
253 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 ...
3
votes
1answer
1k views

Purpose of certificates signed and trusted by CA

Another newbie question but I just don't get the purpose of certificates signed and trusted by CA. We already have public/private keys, hash functions to sign/encrypt messages so why do we need ...
12
votes
3answers
558 views

Incorrect use of HTTPS?

When I open https://java.com my browser says “untrusted connection” but when I open https://www.java.com my browser says it’s ok. But it's the same site. So my question is: Is this a security bug? ...
2
votes
2answers
554 views

How to make a certificate encrypted flash drive?

I was wondering if it possible to encrypt a flash drive (or any other external medium) using certificates instead of a password. The idea is to have a number of encrypted pendrives that can be used on ...
14
votes
4answers
1k views

Is my Company Tracking Me?

Every time I try to connect to a site through HTTPS from my office computer, there is a Certificate Error thrown 2-3 times before showing the login screen. Till now I use to ignore this and click ...