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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What Key Usage values are required to support Code Signing?

I have a .pfx that I want to use to sign a Clickonce app. However, on trying to do so, Visual Studio gives me "The selected certificate is not valid for code signing." When I go to certmgr.msc and ...
3
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2answers
141 views

Can a CN-only certificate bypass a name constraint if the CA goes rogue?

I am trying to cross-certify an internal issuer certificate, adding a name constraint for our domain. However, it seems that an attacker could bypass this protection by putting the desired host name ...
7
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2answers
14k views

Is it technically possible to configure two different SSL certificates for the same domain?

Say I have these URLs: https://example.org/ https://example.org/criticalpath I want the first one to be served with a domain validated commercial SSL certificate and the second one with an ...
1
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0answers
164 views

MQTT (Mosquitto) certificate SSL23_GET_CLIENT_HELLO:unknown protocol [closed]

I'm been desperately trying to get my MQTT clients to connect to my MQTT broker which is set up with a certificate from a CA. To be able to get the CA certificate, I've used the letsencrypt python ...
11
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3answers
452 views

How will SHA1 deprecation affect internal CA's?

I am hearing that the SHA1 Deprecation notices from MS/CHROME only apply to certs that are a part of a public trusted root program. This makes one believe that IE will have new logic built in to allow ...
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1answer
112 views

How to force browser to ask user to resubmit certificate after a logout

We have a website which supports form based authentication (i.e. username and password based) and certificate authentication where a user submits his or her certificate, the username is extracted from ...
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2answers
56 views

Using client certs issued by a third party CA

I have a site that is protected with a user name/password login. For users that want to enter a certain area of the site, there is (legacy) code that looks for a client certificate and if the email in ...
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1answer
81 views

ECDSA implicit certificate using OpenSSL

I am trying to generate implicit ECDSA certificate only for signing and verification using OpenSSL. I tried google but I am getting many research papers. I understood that A messages need to be signed ...
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3answers
114 views

What implications does the KeRanger infection have for Mac OSX security?

Recently some hackers replaced installers for a popular torrent client with an infected version. According to paloaltonetworks, they have no idea how the hackers managed to do this (let's just assume ...
0
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1answer
119 views

CSR with only public key with openssl

So I have been doing my research and haven't found anything specific enough to my problem. As the question title states, I want to make a CSR with only the public key. What I have been able to do is ...
0
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2answers
124 views

How In-House Certificate Authority works (e.g. EJBCA)

I have a simple (dumb?) question with respect to EJBCA. I have been exploring how In-house CAs work and issue certificates. However, I am not able to understand who will be trusted on the top level in ...
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2answers
155 views

Why is weakness of SHA-1 considered a threat to TLS security

If I understand correctly the role that a hashing algorithm (e.g. SHA-1) plays in TLS certificates is as follows: The hashing function is applied to a subject's public key. The CA then uses their ...
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2answers
51 views

Client verification with PKCS#7

When a client sends you a pkcs#7 file to communicate with you, Is this because the file has their public key(certificate) and their chain and to avoid the confusion on your side what needs to be there ...
0
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1answer
74 views

What is the difference between a certificate, a signature and a thumbprint in case of windows exe/binaries?

I am trying to understand the difference between signature , thumbprint and certificate in context of windows executable and binaries. I looked up on internet before posting this question but I did ...
1
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2answers
76 views

Reissuing certificates with SHA-2

I recently setup my own CA, and imported the CA cert into devices across the company. I then deployed certificates to our various servers, etc.. All using SHA-1 signatures (the default in the tool I ...
3
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1answer
149 views

Understanding how does certificate validation work

I'm using Wireshark for better understanding how is a SSL connection established. I captured the traffic of visiting three pages: reddit, facebook and this one. All HTTPS of course. Reddit: after the ...
18
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3answers
4k views

Are there any downsides to using Let's Encrypt for a website's SSL certificates?

On the advantages side, I see several benefits to using the Let's Encrypt service (e.g., the service is free, easy to setup, and easy to maintain). I'm wondering what, if any, are the disadvantages to ...
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1answer
140 views

TinyCA missing CRL information in root and leaf certificates

I setup a new CA using TinyCA. When creating the CA i used an internal host name for the crl url exactly as follows: http://myserver.com/crl.pem And I have exported the CRL to that location, and I ...
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0answers
27 views

Finding the EMSA-PKCS1-v1_5 DigestAlgorithm field in the x509 certificate

From the RFC - https://www.ietf.org/rfc/rfc3447.txt A.2.4 RSASSA-PKCS1-v1_5 For each OID, the parameters field associated with this OID in a value of type AlgorithmIdentifier shall have a value ...
7
votes
3answers
730 views

Risk in buying an SSL cert from a not well-known party

Let's say I know a guy is selling an SSL cert at a very low price, assume they will generate a real and valid cert for me, since I need to submit my CSR to them and they pass to the CA, are there any ...
7
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2answers
545 views

Will Google block HMAC-SHA1 along with SHA1 signed certificates?

So, right now, there is a push for moving from SHA1 signed certificates to SHA256 signed certificates by Google. My understanding is that you cannot use SHA1 for signing certificates but HMAC-SHA1 can ...
82
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4answers
11k views

What prevents me from buying a SSL certificate for a domain I don't control?

Can I simply build a webserver, make its hostname "google.com", create a CSR off that server, and send that to a Certificate Authority for signing? Let's say I pick the cheapest and dodgiest outfit I ...
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2answers
54 views

Using mutual authentication, should I still worry about message integrity and replay attack?

I'm trying to secure a REST API, our situation is that every client connecting to this API will also have a certificate signed by our own CA. Because of this, I think we can use the client certificate ...
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0answers
50 views

How Do I Create a Production Client Authentication Certificate for Azure Key Vault?

I am learning about Azure Key Vault, and one of the scenarios it supports is certificate authentication, which you can read about here. The samples do a great job of explaining how to make a self-...
3
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2answers
122 views

When should I renew certification authority?

What is best practice in renewing certification authorities? I mean when should I renew certification authority? For example, suppose I have the following setup: 1. Root CA with validity of 30 years ...
3
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1answer
172 views

Is It OK If a Server Does Not Verify a Certificate?

I am currently learning a LOT about Azure, Azure Active Directory, and Azure Key Vault (AKV). To start with, please see this article: In particular, I am interested in this statement: When ...
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1answer
158 views

What does browser do when it queries xxx.example.com and it gets a certificate for yyy.example.com(top level domain is same)?

The question is actually about what level of validations browser does when it gets certificates of some other domains like case 1: Accessing abc.google.com and got def.google.com case 2: Accessing *....
20
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1answer
16k views

4096 bit RSA encryption keys vs 2048

Where do 4096 bit RSA keys for SSL certs currently stand in terms of things like CA support, browser support, etc? In the overall scheme of things is the increased security worth the risk of 4096 bit ...
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0answers
36 views

How do the eduroam WPA-Enterprise 802.1X certificates look like?

As outlined in another answer, the official eduroam WiFi profiles available from https://cat.eduroam.org/ (verified for uWaterloo and uOttawa), as well as sample official instructions of the ...
2
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2answers
135 views

Self-signed cert - how it works

I am new to SSL / digital certificates / signatures. What I know is that a digital signature must be verified/decrypted using the public key. So a cert that is signed by a CA must be verified/...
6
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1answer
121 views

S/MIME certificates and “information leakage”

I'm considering getting an S/MIME certificate that verifies my name and email address. I've been trying to ascertain what information "leaks" if I do. The Wikipedia page on S/MIME says: Depending ...
16
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4answers
30k 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 ...
54
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9answers
18k views

Should I change the private key when renewing a certificate?

My security department insists that I (the system administrator) make a new private key when I want a SSL certificate renewed for our web servers. They claim it's best practice, but my googling ...
4
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1answer
103 views

SSL/TLS: Policy Constraints vs. Basic Constraints

Could someone please explain the difference between Policy Constraints and Basic Constraints? It appears to me that they are either redundant, or two names for the same thing. I would love some ...
0
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1answer
117 views

Mutual Authentication and Authorisation with Certificates from various CAs

Edit: Having read this question and answer I have a bit more of an understanding. My question now then, is: can I use a certificate that a user has had signed by a registered CA such as VeriSign, ...
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2answers
113 views

Why did I get a wrong IP and certificate for www.facebook.com just now? [closed]

I just navigated to www.facebook.com and my browser alerted me that an invalid certificate has been received. I checked the cert in question, and I was surprised to see that the Common Name on it was ...
5
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3answers
836 views

Certificate Transparency

From what I read here, if the intermediate CA has been compromised, a fake cert can be issued and the privacy of the end-users could be compromised as well. In order to remediate this situation, ...
2
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1answer
3k views

Intercepting HTTPS Android app traffic

I'm trying to intercept Android application traffic from my Android phone....Basically what worked before was that i had simply installed fiddler proxy on my PC, exported the root certificate (and ...
12
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3answers
5k views

What elliptic curves are supported by browsers?

Wireshark'ed Firefox 3 request. Their names are nowhere documented. Elliptic curve: secp256r1 (0x0017) Elliptic curve: secp384r1 (0x0018) Elliptic curve: secp521r1 (0x0019) What are the supported ...
6
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1answer
196 views

Client identification using client certificates

I have the following scenario: Several independent embedded servers (Linux/ARM/lighttpd) Several independent controlling devices (win32/iOS/Android) Each server should have at least one controlling ...
2
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1answer
81 views

How do “certificates” hold “keys”? [duplicate]

I am new to the realm of security and keep hearing about "certificates" containing "keys". But no one has been able to actually explain to me what is actually meant by this. I assume that the ...
2
votes
3answers
343 views

HTTPS client certificates for server-to-server

Say you have two servers with certificates proving their domains (e.g. for use with HTTPS). Can one of these servers use their certificate as a client certificate when talking to the other, so that ...
1
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1answer
122 views

What can a trusted certificate do?

I am doing some reading about security on mobile applications because I found an article about Man in the Middle Attacks. I saw in that article and in many other places (including security....
3
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2answers
3k views

Client certificate for 2 way SSL works in some programs, and fails in most

I am trying to establish 2 way SSL connection with remote server and I have received certificate to connect. Can somebody explain behaviour described below. I am able only to use it with SOAP UI ...
57
votes
2answers
131k views

Difference between .pfx and .cert certificates

What is the difference between .pfx and .cert certificate files? Do we distribute .pfx or .cert for client authentication?
3
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6answers
6k views

How can I know that the CA certificates in my computer have not been spoofed?

As far as I know, the browser contains the certificates of several CA. When I access http://gmail.com, the site says it is Gmail, it exposes a certificate signed by one of the CA I have in my ...
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1answer
48 views

HTTPS - if this protocol protect against connecting to false server?

I know about SSL certificates. However it is ok to say: protocol HTTPS protects against connecting to false server ?
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1answer
19 views

Certificate Setup Over Many Remote Resources

Imagine that you have a web app that needs to talk to a central api server with its purchased certificate. This server provides a token to the web app to be used to authenticate and talk to another ...
2
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2answers
97 views

Why do we need certificates confirming certificates?

Why do we need certificates confirming certificates? Why create a hierarchy or tree? These questions makes me confused, could you explain it me?
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1answer
2k views

ADFS: Verify requests from relying party

In ADFS, serveral certificates are used. This is explained (very clearly) on this page: http://blogs.technet.com/b/adfs/archive/2007/07/23/adfs-certificates-ssl-token-signing-and-client-authentication-...