Questions tagged [certificates]

A piece of data used in public key cryptography (specifically public key infrastructures) 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. For questions specifically about [x509], [certificate-authority], or [public-key-infrastructure], please use those tags.

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6answers
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Is it secure to consume services over HTTPS which is not signed by a trusted CA?

I am building a client application that will consume a web-service application provided by a third party service provider. The service is exposed with a HTTPS URL that is not signed by a trusted ...
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What prevents a man in the middle from requesting a certificate for your server?

Let's say you have a server at shop.example.com and you are requesting a certificate from some trusted CA like Comodo (they say they'll issue it within few minutes online). First of all, how can they ...
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Are login “certificates” more secure than standard username + password authentication?

I just opened a new bank account which comes with internet banking. Unlike the others I have used so far, this one requires a personal certificate (a .p12 file stored on my computer) + password for ...
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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 ...
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Why would the BBC web site always ask for a personal certificate, and how do I avoid giving it away?

After installing a CAcert personal certificate, every time I land on the BBC weather site it asks me to identify myself with a certificate. Why would any non-malicious web site do that unless I've ...
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What elliptic curves are supported by browsers?

I Wireshark'ed a Firefox 3 request, because I couldn't find the curve names documented: Elliptic curve: secp256r1 (0x0017) Elliptic curve: secp384r1 (0x0018) Elliptic curve: secp521r1 (0x0019) What ...
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Is HTTPS required for local network server to server communication

I am building web applications for my customer's company. At the server side, there will be 2 kinds of server to server network communication. Separated REST API servers making requests among each ...
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3answers
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Is SHA1 weak for SSL?

I noticed that today after I scanned a site on the Qualys SSL Labs site that SSL ciphersuites which use SHA1 are now highlighted as being "Weak". It seems this has just happened; I scan sites pretty ...
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Cloudflare's free SSL options require trusting them; what could they do to change that?

Cloudflare offers 3 free SSL options: Flexible SSL, Full SSL, and Full Strict SSL. The article “CloudFlare’s great new features and why I won’t use them” explores the shortcomings of the Flexible and ...
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How to know if certificate is self-signed

How do I find out if a certificate is self-signed or authorized by CA? Somewhere I read that self-signed subject and issuer will be same, is it correct?
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Can an HTTPS server accidentally leak its private key?

Are there any known cases of HTTPS websites leaking the private key of their SSL certificate? Is it even technically possible for a bad website admin to misconfigure a site to send the private key as ...
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Who is responsible for revoking a certificate?

The CA issues certificates to clients/servers. Whenever a request is made by the client/server, the certificate is used to verify the identity. Now, if a certificate needs to be revoked then who does ...
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3answers
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A Different Approach to PKI

After yet another failure of the public key infrastructure, I was thinking about how broken the whole thing is. This business of undeniably associating an identity with a public key, and all the work ...
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Why don't folks seem to use ECC for TLS root certificate signature?

I looked around, and all I see is websites using RSA2048 for Root signature, and a few using ECC for encryption. Are there any reasons folks don't seem to use ECC for TLS root signature? Are there ...
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Possibility to sniff HTTPS traffic on devices without installing a certificate

My goal is to sniff the HTTPS traffic of some digital devices (AppleTV, game consoles, etc.), and decrypt the HTTPS packets in my local network. I cannot figure out a way by using some HTTPS ...
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Superfish vs. Corporate MITM

I work for a consulting company, and I have been implementing a tool from a security vendor, which is a cloud proxy for all user traffic. It will perform malware scanning and filtering of all web ...
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What happens when an Intermediate CA is revoked?

Currently I’m working on a certificate manager that allows our product to securely connect to remote web services (over TLS/SSL). For security, we use Certificate Revocation List checking (or CRL-...
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3answers
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Anything to do about old gpg keys?

Quite A few years ago (in middle school) I created some gpg keys, published them to a keyserver, etc. because I was l33test kid on the block. Now I have gone through a few new computers and OS's, etc....
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5answers
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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?
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3answers
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What issues arise from sharing a SSL certificate's private key?

Scenario: I am hosting a website for a my client, who we'll call S. S owns the domain s.com and I own the servers that actually host the website. S now wants to enable SSL on their website. I have ...
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How can I prevent that my users get a certificate issued for my domain on my behalf?

I have a domain, where some other users have access to upload files, use email, use XMPP, etc. How can I prevent that these users go to a certificate authority and get a certificate for my domain? ...
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1answer
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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.
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Alternatives to HTML's deprecated <keygen> for client certs?

The keygen tag is used to make browsers generate private keys and POST the resulting CSR to the server, which can then issue a certificate. It's now been deprecated, for rather stupid reasons but that'...
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2answers
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Is it safe to publish a private CA's root and intermediate certificates?

Context: We have a private certification authority in my company. We are provisioning VMs in our private cloud which will need to trust SSL certs issued by this CA, i.e. they will need the cert chain ...
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4answers
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What is the potential impact of these SSL certificate validation vulnerabilities?

I just finished reading through this paper by Georgiev et al, which demonstrates a wide range of serious security flaws in SSL certificate validation in various non-browser software, libraries and ...
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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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2answers
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How much of a problem is it that Windows “hides” some of the trusted root CA certs?

Based on information on this page, Windows actually trusts many more root CA certificates than what are displayed when a user launches certmgr.msc and navigates to Trusted Root Certification ...
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7answers
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Is encryption still applied if you ignore the SSL certificate warning for self-signed certs?

Would encryption still be applied on communication with devices using self-signed certificates if you ignore the warning and proceed without installing the certificate? Would you need to install it to ...
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8answers
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Is Spoofing a CA signed certificate possible?

I had never thought about this situation before, I may be completely wrong but I am going to have to clarify it anyway. When a communication starts with a server, during the client handshake, the ...
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Why are certificates limited in time?

If a certificate has a limited duration of, say 5 years, but it gets somehow compromised after 2 years, waiting the 3 remaining years for it to get invalid is not a real solution to the breach problem....
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Dealing with SSL Certificates on Products

We are developing a product (device / system) that will be installed on customer sites. Many of our customers will (should) be concerned about security, and should be thinking about it seriously. Our ...
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2answers
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OpenSSL generate different types of self signed certificate

Does anyone know how to use OpenSSL to generate certificates for the following public key types: DSA - For DHE_DSS key exchange. Diffie-Hellman - For DH_DSS and DH_RSA key exchange. ECDH - For ...
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What are the risks of a Certificate Authority hack for 'the average user'?

Recently the DigiNotar CA was hacked, and rogue certificates were issued. Since they also issue certificates on behalf of the Dutch government, the government made a statement about it as well, ...
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Is it possible to use wildcard certificates on multiple devices?

I have a server that I want to use a wildcard cert on. It runs multiple services. I purchase a wildcard cert so that I can protect mail.something.dom, www.something.dom, im.something.dom, calendar....
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7answers
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How do I check if a gmail/gtalk SSL certificate is valid?

Pidgin started prompting me to accept/reject new gtalk SSL certificate a few days ago and I am not able at the moment to tunnel the traffic to check if it would continue to happen or if it wouldn't (...
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3answers
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Chrome SSL Warning: “You cannot proceed because the website operator has requested heightened security for this domain. ”

I'm trying to go to the URL below, and Chrome warns me that the wildcard certificate is not valid for this domain. https://chart.apis.google.com/chart?cht=qr&chs=100x100&chl=otpauth%3A%2F%...
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6answers
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Is there a protocol that provides data integrity, but not encryption for HTTP?

HTTP I'm aware that HTTP sends plain text over the network which can be sniffed and modified if a MITM is performed. HTTPS On the other hand, HTTPS sends encrypted text over the network that can ...
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3answers
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Are certificates without DNS fundamentally flawed?

I am new to security work and I am implementing someone else's design. The design calls for a TCP server with TLS in an environment where there is no DNS - only IPs. I am working with a typical ...
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2answers
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Why does rfc6797 say “An HSTS Host MUST NOT include the STS header field in HTTP responses over non-secure transport.”

Why does the RFC prohibit the server from sending HSTS to the client over HTTP? I can see that if a HTTP client responds to that unsecure HTTP response it might cause that site to be inaccessible ...
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2answers
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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 Most ...
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3answers
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Which signing key should I use for certifying other peoples public keys: master or subkey?

I have a Master Identity key (which is detached from my daily-use keyring) and both encryption and signing subkeys (all are RSA). I sign documents with the signing subkey: GnuPG selects this key ...
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4answers
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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 ...
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3answers
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How to reset Windows trusted certificates store to its default [closed]

Over time I have installed several additional trusted CA certificates to Windows trust store, sometimes because an app pushed me to do so, other times for reasons of development and testing. Is ...
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3answers
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what do you do when an ssl certificate expires and your app uses ssl pinning?

I originally posted this question on StackOverflow, but reposted here due to lack of responses. I am trying to decide if it's a good idea to do ssl pinning in my iOS game that uses a server to ...
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5answers
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Does Google use extended validation certificates?

I just changed a password on a Google account while using the Chrome browser. After doing so, I noticed that the https connection to Google was not highlighted in green signifying that it was an "...
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2answers
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Secure communication between applications using SSL Certificates

I am looking for a way how to secure communication between our applications. There is a "server" application listening on some TCP port and "client" application which is communicating with the "server"...
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1answer
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PEM, CER, CRT, P12 - what is it all about?

I hope my question is not too general, but I find the topic of storing asymmetric keys very confusing.. Here's how I understand it: Using openSSL I can generate my RSA keys pair: openssl genrsa -out ...
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2answers
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SSL fingerprint inconsistency: what does it mean?

I apologize if this is not the best place to ask my question on the Stack Exchange network, I couldn't figure out where to get enough attention and be relevant. Facebook provides a SSL host, it can ...
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2answers
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Do browsers know domains that are supposed to be encrypted?

Do browsers have a list with sites that are supposed to be encrypted? Could a man in the middle attack be performed by presenting a user a http site instead of an https site? That way the server would ...
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2answers
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Is Certificate validation done completely local?

Am I right in my conclusion that validation of a certificate by a client that wishes to communicate with a server that offers said certificate, is done completely local? As in, the client is supposed ...

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