Questions tagged [x.509]

X.509 is a 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.

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8
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2answers
20k views

Use openssl to individually verify components of a certificate chain

This is related to another question, How to verify a signature of one entity by another using OpenSSL CLI? I used openssl s_client -showcerts -connect www.google.com:443 to collect three certificates ...
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Missing X509 extensions with an openssl-generated certificate

My goal is to create a certificate with opensslsimilar to this one generated with cfssl Certificate: Data: Version: 3 (0x2) Serial Number: 60:44:dc:0d:80:f4:54:55:e8:...
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1answer
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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 ...
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How to validate a client certificate

My understanding is that when using a client certificate for security one issues a private and public key cert (for example X509) of some sort and sends that of to the consumer of the service that one ...
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2answers
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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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2answers
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What is the difference between serial number and thumbprint?

I have problems to understand what is the difference between the serial number of a certificate and its SHA1 hash. The MSDN says: Serial number A number that uniquely identifies the ...
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2answers
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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 ...
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3answers
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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 -...
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WPA2 Enterprise EAP-TLS Key Exchange

I'm in the process of implementing 802.1x WPA2 Enterprise Authentication using FreeRadius and EAP-TLS (Mutual TLS Cert Based Auth). I am keen to understand how to actual protocols work together and ...
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2answers
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Gmail X.509 certificate chain

I have asked about this on several forums but never got a straight answer. If the root certificate on a certificate chain has a different fingerprint to the root certificate available for download on ...
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1answer
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Generate X509 ERR_CERT_COMMON_NAME_INVALID

I am trying to set up https server on python3, but I could not generate a certificate and a key properly. That is the server code: import http.server, ssl server_address = ('localhost', 4443) httpd =...
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2answers
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Determine if private key belongs to certificate?

Given a certificate¹ and a private key file², how can I determine if the public key on the certificate matches the private key? My initial thought was to simply encrypt some text with the public key ...
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1answer
19k 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 ...
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1answer
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Why is there no certificate error while visiting google.net although it presents a certificate issued to google.com?

The following output shows that google.net is presenting a certificate that has been issued to www.google.com. $ openssl s_client -connect google.net:443 < /dev/null > out.txt 2>&1; cat ...
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2answers
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Validating an SSL certificate chain according to RFC 5280: Am I understanding this correctly?

we're in the process of replacing certificates with SHA1 hash due to Google's move to let them appear less secure in Chrome. The replacement certificates use a different intermediate CA than the ones ...
13
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1answer
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Encrypting local HTTP traffic using a self-signed certificate

For the past couple of hours I've been trying to create a self-signed certificate which I'd like to use to encrypt HTTP traffic between computers and a server on my home network (because I'm paranoid ...
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3answers
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What is the use of cross signing certificates in X.509?

In X.509 architecture what are the uses of cross signing certificates from other hierarchy? Does it just expand trust? So from the answer I am assuming that if CA3 is cross signed by CA2 (from ...
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2answers
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How is an X509 certificate signer verified?

Lets say I create a self-signed X509 certificate A and use it to issue certificate B. I put certificate A in my trusted root authorities so that all certificates signed by it are accepted. My question ...
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1answer
11k 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 ...
5
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1answer
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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 ...
2
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1answer
4k views

How to extend x509 certificate validity

I have two x509certificate, and now they are expired. What I would do is to extend the validity date of these certificates (I don't want t creat new one). Can I do this with openssl or other tools ?
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1answer
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Why is the Signature Algorithm listed twice in an x509 Certificate?

Section 4.1 of RFC 5280 defines the contents of an x509 Certificate. Specifically, two fields are listed (signatureAlgorithm and signature) and defined to contain the same information: ...
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2answers
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Recommended key usage for a client certificate

My program has the following flow: a client sends a CSR to server, the server sends back a client certificate and after that the client communicates with the server to a path that requires a ...
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2answers
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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 ...
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1answer
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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 ...
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1answer
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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 Ltd./OU=...
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1answer
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How to verify a signature of one entity by another using OpenSSL CLI?

I'm teaching a class about certificate chains, so I download the chain from www.google.com which has 4 certs. I want to demonstrate how the dependencies work from issuer to subject by showing that ...
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2answers
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X.509 certificate renew vs. rekey

What is the difference from CA perspective between renewal and rekeying of the certificate previously issued by this CA?
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1answer
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Subject Alternative Name in Certificate Signing Request apparently does not survive signing

So I have been able to create a Certificate Signing Request with a Subject Alternative Name of the form subjectAltName=IP:1.2.3.4 by following the recipe in a previous (splendid) answer. When I ...
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4answers
5k 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?
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3answers
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SSL/TLS Certificate Update?

We had a setup which used openssl0.9.8 so it had only support for SSLv2 and TLSv1.0. We had a script which generates self-signed X.509 certificates and uses openssl library. Now we have upgraded ...
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1answer
784 views

How does do client authentication work over https?

I recently wrote an application that calls out to a 3rd party service to perform some work. This 3rd party service requires that I authenticate the client calling by using a client certificate. For ...
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4answers
9k views

Can an intermediate CA be trusted like a self-signed root CA?

Is it possible within the limits of the X.509 specification to mark an intermediate CA as trusted for a specific purpose, e.g. to verify a VPN, HTTPS etc. server key, just like it would work with a ...
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1answer
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Root certificate key usage (non-self-signed end entity)

This discussion does not include self-signed end entity certificates for hosts like web servers and mail servers. OpenSSL's default configuration for a CA certificate has the following keyUsage: ...
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2answers
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How TLS certificate chain is verified

Assume the verification of a TLS certificate chain. Suppose the chain has certificates A-B-C-D where D is the root certificate and A is signed by B, B by C, C by D. Suppose the intermediate ...
14
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2answers
9k views

Are certificate authorities required to obey to the signature algorithm (hashing) specified in the CSR?

I was playing a little bit with signature algorithms, trying to determine which CAs among the ones I use are currently issuing SHA2 certificates. I generated a CSR specifying the SHA256 hash (either ...
11
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2answers
3k views

How to properly create and use cross-signed CAs and certificates

I'm trying to create an environment with cross-signed CAs, and verify a certificate issued against one of the CAs, all using openssl. The best I got so far is getting openssl into an endless loop ...
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2answers
9k views

Extensions for SSL server certificate

I have some question about the X.509 v3 extensions. What extensions should appear in a proper certificate for a SSL server ?
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3answers
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What are the accepted naming convention for the terms “public/private keys” and “certificates”?

Is there an accepted naming convention for referring to PKI artifacts? There seems to be a lot of confusion with the naming of artifacts. For example, it seems that some people refer to: public ...
5
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1answer
3k views

Is it 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, ...
11
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1answer
2k views

Are X.509 nameConstraints on certificates supported on OS X?

I have the following "chain" of certificates on a test machine right now: A self-signed CA cert, in my Keychain and trusted & trusted by Firefox. A CA cert with with the following, X509v3 Name ...
6
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1answer
17k 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?
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3answers
519 views

Generating deterministic X.509 certificates?

Is there a way to deterministically create an RSA private-key for an X.509 certificate, ideally through a library which has been vetted already? i.e. user enters some phrase like "this is my private ...
4
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1answer
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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 ...
4
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1answer
296 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 ...
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4answers
3k views

Trust a non-root CA in OpenSSL

Is it possible to have OpenSSL trust a non-root CA such that a certificate signed by that non-root CA can be properly verified? I've noticed that the default behavior for OpenSSL is to only verify ...
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2answers
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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 ...
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2answers
12k views

Does openssl refuse self signed certificates without basic constraints?

I have two extremely similar self signed certificates, generated via two different methods. To test them I have: Added an entry in my hosts file for local.mydomain.com Set up an nginx server to ...
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1answer
3k views

how do extended validation X.509 certs work?

https://www.forumatic.com/ uses an extended validation cert. wikipedia.org's entry on extended validation certs says that a cert is known to be an extended validation cert if the OID in the ...
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2answers
400 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 ...