X.509 is an standard for a public key infrastructure used for authentication and access control. X.509 specifies standard formats for certificates, revocation lists, attribute certificates, and path validation.

learn more… | top users | synonyms

1
vote
1answer
20 views

Cross-certification between worlds like X.509 and PGP?

Sometimes it can be advantageous to use existing trust relationships in one certification world - X.509 or PGP - to create trust in the other world. At the lowest level I can always take an X.509 cert ...
0
votes
1answer
16 views

Validating the ROA certificate

Suppose I have a system, where the server requires the clients to attach their ROA certificate to prove that they have the right to that IP Prefix. Now if the client attaches the ROA certificate ( ...
1
vote
1answer
29 views

TLS Certificates only for Clients

I'm aware that sites like StartSSL use Client-Certificates, I opened mine in Firefox and it showed me: "SSL-Client-Certificate", "E-Mail-Receiver-Certificate", "E-Mail-Signer-Certificate". Now I'm ...
0
votes
1answer
57 views

Limiting a CA to only issue valid certificates to internal web sites and clients

What are the possible defense measures that can be applied to a simple PKI (no intermediate CAs, etc.) used to authenticate clients and servers over TLS on an internal network only? Certificates ...
2
votes
1answer
114 views

Security Structure of an API

I've been developing a web application and APIs for 8 months. I implemented OAuth 2.0 client credentials for authentication. And now I have to implement TLS to my APIs. I've been dealing with SSL/TLS ...
6
votes
1answer
892 views

Is Man-In-The-Middle necessary for a CA to read HTTP plaintext?

Although I understand the basic theory behind certificates and asymmetric cryptography, I'm not quite sure on the details of the X.509 protocol. I'm wondering what attacker model a given CA requires ...
0
votes
0answers
84 views

What is the difference of TrustManager PKIX and SunX509?

Java's JSSE provides two different TrustManagers: PKIX and SunX509 I tried to find out what the differences between both are, but couldn't find any in the documentation. Can you tell me the ...
12
votes
1answer
945 views

Relationship between RSA, Diffie-Hellman Key Exchange, PKI and X.509?

I am getting confused with RSA, Diffie-Hellman Key Exchange, PKI and X.509v3. I took a look of RSA's mathematics algorithm, it seems like a encryption algorithm, right? Generating public key and ...
0
votes
1answer
356 views

Sign PKCS#7 and verify PKCS#7 signature with OpenSSL

If someone have to transfer X.509 certificates in a single bundle, usually, it is recommended to pack them into PKCS#7. And content of PKCS#7 can be signed. OpenSSL allows to pack certificates into ...
0
votes
1answer
82 views

Why do private networks use both X.509 and User/Password authentication

For example, the school network I am on requires both a name & password to log in along with having its X.509 certificate installed in my browser. Why does it need both? Shouldn't name and ...
3
votes
3answers
110 views

How to determine if an X.509 certificate is a renewal of another known certificate?

In my application, the human user accepts the server's X.509 certificate, verifying the fingerprint during the first-time connection. The fingerprint is stored in the client software. At later ...
0
votes
2answers
261 views

cross-signed end-entity certificates: usage in apache/openssl/gnutls

A previous question, What is the use of cross signing certificates in X.509? described cross-signed certificates well. I have a situation where the clients trust CA1 xor CA2, and both need to reach a ...
6
votes
2answers
7k 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 ...
2
votes
2answers
148 views

The reason to insert Subject Alternative Names into CA certificate

I am trying to understand meaning of the Subject Alternative Name extension. The reason of usage it in SSL X.509 certificates or other end-entities certificates is mostly clear for me. However, I ...
3
votes
1answer
363 views

Self-signing client certificates and distributing them, is the following a sound procedure?

I have a case at hand as follows: There is a number of clients in Internet (i.e. untrusted channel), initially in hundreds but growing in numbers. There is a server doing processing related to these ...
1
vote
1answer
377 views

How to safely renew user and CA certificates in a PKI

I am currently developing my own PKI where x.509-client-certificates are issued by a public server. At the moment, the CA-public key is distributed with the binary and there are no routines for ...
0
votes
1answer
274 views

What is the difference between openssl and mkcert and IIS self signed certificate

What is the difference between openssl and mkcert. Which one should I prefer. I want to create an IIS hosted WCF service. Which one should I use to create an SSL certificate. Also, there is another ...
1
vote
2answers
141 views

determine X.509 certificate class

I am very familiar with OpenPGP but don't even use X.509 / S/MIME. I know that there are several classes for certificates (from email check to personal ID check). I would like to know how you ...
4
votes
1answer
209 views

Do SSL / X.509 certs cover all ports for a host?

Or are certs both host- and port-specific (excepting wildcard certs)? I would assume they aren't, because they're supposed to verify a domain, but at the same time I've never seen anyone run HTTPS on ...
0
votes
2answers
133 views

How to encode a username in PKIX certificate?

I was reading through RFC 5280, PKIX Certificate and CRL Profile, Section 4.2.1.6, Subject Alternative Name: The subject alternative name extension allows identities to be bound to the subject ...
0
votes
4answers
274 views

Can a certification authority sign another CA's certs?

Disclaimer: I have low knowledge of X.509 and PKI, so I would appreciate an answer that is not entirely technical, i.e. by using real-life example scenarios.) I was searching for information ...
0
votes
1answer
185 views

Certificate request - why does the requester have to create a private key?

If remember right, then before I send a CSR (Certificate signing request) to the CA, I have to create private and public keys. Then I use the public key to encrypt my personal details before I send ...
1
vote
0answers
43 views

Kohnfelder Certificate [closed]

The Kohnfelder certificate standard is very similar to that of X.509 certificate standard. Comparing the two standards, does one have an advantage edge over the other? or what are the pros and cons of ...
0
votes
2answers
222 views

can a x.509 certificate alone be used for user authentication?

we have a scenario for implementing SSO using x.509 certificates. A secure client will download a x.509 certificate (only certificate...no private key is available) upon user logs into the windows ...
4
votes
1answer
3k views

Certificate verified using two different paths

StartSSL has an intermediate certificate that they use to sign their EV certificates: sub.class4.server.ca.pem. This certificate's issuer is shown by openssl x509 to be /C=IL/O=StartCom ...
1
vote
0answers
104 views

Deploying software that requires X.509 certificates

I have a self-hosted WCF application, with a server application running on the server (obviously) and a client application that will be installed on the users PC. Up until this point I have been ...
2
votes
2answers
493 views

Why do public key certificate “Trust anchor”? Does this introduce a single point of failure?

When you look at currently used concept of Root CA (primarily in SSL/TLS context), you can see a single-point-of-failure vulnerability, which means, if your private key is disclosed, you automatically ...
1
vote
1answer
257 views

Can anyone explain how to use an X509 client certificate to securely authenticate a user?

Bit of background. Web Application that can generate Pub/Priv Keys and X.509 certificates. How would I make use of the certificate in a web application, username and password login form to provide ...
1
vote
4answers
5k views

inquiry about SHA1 with RSA for certificate signature

As you all know, plenty of X.509 Certificates use (PKCS#1 SHA1 with RSA encryption) as the Certificate Signature Algorithm for generating the signature of 2048 Bits long. We know that SHA1 hash ...
5
votes
1answer
672 views

Is is typical to create both x509 and OpenPGP key pairs?

I'm looking into increasing my use of signed and encrypted "things" - LibreOffice Documents, Off-the-record chat, PDFs, emails, etc. I'm finding that some things only support x509 format-certificates, ...
5
votes
1answer
611 views

How is an Authenticode timestamp verified?

For an Authenticode signed file to be verifiable by Windows after the original signing certificate has expired (typically 1-3 years after issue), the file also needs to have a cryptographically signed ...
1
vote
2answers
301 views

Choosing the right X.509 certificate infrastructure for securing LAN communications between a PC and a device

Edit: seems like I was quite hasty when typing in my question at first, so here is an updated version of it. I am developing an application that runs on PCs which are on the same LAN as other ...
-1
votes
2answers
101 views

user identity certificate

I want to create a new scheme for user identification, like X.509 certificates, but not X.509. Is it possible to use this new certificate over the existing Internet? and if yes, what are basic ...
1
vote
1answer
110 views

Two way delegation?

I am looking into using the X.509 for mutual delegation where mutual delegation is bi-directional where an entity can only delegate a task or a set of permissions to another entity if the latter is ...
0
votes
1answer
290 views

SSL (TLS v1.2) - Can i offer fallback CAs when upgrading Certificates? (Java)

I am currently developing a product that involves two network situations. At the client side, multiple computers form a P2P network (multiple locations, multiple p2p networks), and a subset of nodes ...
3
votes
3answers
625 views

accepted naming convention for public keys/certificates

Is there an accepted naming convention for referring to PKI artifacts? There seems to be a lot of confusion with naming of artifacts. For example, it seems that some people refer to: public keys ...
3
votes
1answer
200 views

Why is the issuer name field signed in X.509?

In the X.509 specification it sais that the issuer name is to be signed. Since we verify the certificate with the authenticated issuer's public key, it seems infeasible to forge the issuer name ...
6
votes
1answer
573 views

SSL - Null Prefix Attacks Still Possible?

At DEFCON 17 (2009) Moxie Marlinspike gave a talk were he was able to use a malformed certificate signing request to get SSL certs signed for domains he doesn't own. The gist of it was that for the ...
23
votes
1answer
15k views

What is the difference between Serial Number and Thumbprint?

I have problems to understand what the difference between the Serial Number of a certificate and its SHA1 Hash is. the MSDN says: Serial number A number that uniquely identifies the ...
8
votes
2answers
3k views

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 ...
9
votes
5answers
5k views

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 ...
5
votes
1answer
3k views

ECDHE_RSA and gmail

I'm using Chrome on Ubuntu Linux to connect to Gmail. The connection info says that ECDHE_RSA is used for the https symmetric key exchange. Based on my understanding of TLS and Gmail, my client ...
3
votes
1answer
4k views

Enhanced Key Usage vs. Extended Key Usage

I've seen both the terms Enhanced Key Usage and Extended Key Usage, and both were abbreviated as EKU. Do both refer to the same extension or property?
7
votes
1answer
2k views

Why do X.509 certificates have “Key Usage” attribute?

I can find their values and all details in the RFC, but I cannot find why it was decided to have this attribute in certificates, instead of leaving them to be multipurposes. Is there a reasoning ...
6
votes
2answers
4k views

How to use a Yubikey NEO (or any OpenPGP card or GnuPG in general) to sign X.509 CSRs?

Since the Yubikey NEO can be used as an OpenPGP card (see here) with three 2048 bit RSA keys, I thought about creating a CA from one of its public keys. Since the private key cannot be extracted ...
11
votes
1answer
4k views

Which properties of a X.509 certificate should be critical and which not?

RFC5280's section 4.2 states Each extension in a certificate is designated as either critical or non-critical. A certificate-using system MUST reject the certificate if it encounters ...
1
vote
1answer
588 views

How to troubleshoot why Thunderbird rejects a PKCS#12 certificate with “Could not verify this certificate for unknown reasons”?

After playing around a bit with openssl, I created a PKCS12 certificate which imports flawlessly in Firefox while Thunderbird "Could not verify this certificate for unknown reasons". Talk about a ...
2
votes
1answer
769 views

What is the difference between `extendedKeyUsage` and an application policy?

In some Microsoft articles like http://technet.microsoft.com/en-us/library/cc731792%28v=ws.10%29.aspx, I find some confusing statements like Application policies are sometimes called extended key ...
0
votes
1answer
388 views

Does S/MIME provide means to propagate a certificate's revocation?

Can a revocation certificate for an old X.509 certificate be attached to an email in addition to a replacement certificate in such a way that the client user does not have to manually intervene? Or ...
10
votes
3answers
7k views

How to set up OpenSSH to use x509 PKI for authentication?

I do not mean simply putting the public RSA key of a x.509 certificate into ~/.ssh/authorized_keys - I'm looking for a way to set up a ssh such that x.509 certificates signed by a pre-defined CA will ...