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.

Filter by
Sorted by
Tagged with
8
votes
2answers
2k views

Definitions for CRL Reasons

Is there any authoritative definition of the various reasons possible in a CRL file? Section 6.3.2(b) of RFC5280 lists a few: unspecified keyCompromise cACompromise affiliationChanged superseded ...
8
votes
2answers
631 views

How do user receive server's certificate?

Let's imagine our user's computer wants to talk to some server for the first time in history via https. The computer sends a hello message, the server sends his public key and the certificate, ...
8
votes
2answers
15k views

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 ...
8
votes
2answers
2k views

How is certificate forgery with cheap CA's prevented?

In order to perform a successful man in the middle attack on HTTPS, one needs to either strip SSL layer and convert it to HTTP completely or needs to have a valid certificate from a CA for the same ...
8
votes
3answers
4k views

Should antivirus HTTPS scanning be left on? Is it secure?

Some antivirus software MitMs, or through other methods, HTTPS connections in order to scan for malware, for example, Avast, and maybe other vendors too. Is the method they (let's say Avast as an ...
8
votes
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 ...
8
votes
3answers
1k views

Is it ok to have self-signed certificates in source control?

I just asked the question SSL self-signed certificates in development vs acquired cert in production? which has promptly been answered (THANKS!). Out of that, I have the following question: Is it ...
8
votes
1answer
677 views

What to do when Google disables SSLv3 and RC4?

I've read this article from Google's Online Security Blog, and it says that Google will disable support for SSLv3 and RC4. Here's the reason: SSLv3 has been obsolete for over 16 years and is so ...
8
votes
2answers
20k views

Public Key → Certificate?

Is it possible to convert a public key to a certificate using the public key only? I've seen the following, which takes a private key to form a cert request, which can then be self-signed: openssl ...
8
votes
1answer
6k 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 ...
8
votes
1answer
333 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 ...
8
votes
3answers
33k views

TLS library problem when connecting to Dovecot

I have a Comodo PositiveSSL certificate issued for mail.btcontract.com and I've set up Postfix and Dovecot to work with it in the following way: Postfix main.cf: smtpd_tls_cert_file = /etc/ssl/mail/...
8
votes
1answer
35k views

How to get SSL certificate of a mail server?

I need to get SSL certificate of some mail servers. I know I need to do execute following steps. Do a DNS mx query on the domain name (dig google.com mx). Use the information to download SSL ...
8
votes
1answer
17k views

Why is a CA certificate required for EAP-TLS clients?

When setting up clients with WPA2 EAP-TLS, most clients (ie: my phone, my computer) require both a client public/private keypair (for obvious reasons) and a certificate authority certificate. It's ...
8
votes
1answer
6k views

Should I regenerate new SSL private key yearly? [duplicate]

Im' renewing my certificate every year. Since I have to make a CSR, should I also renew my key pair at the same time, or is it ok to get a new cert with the same key ? Please supply any security ...
8
votes
2answers
8k views

Is the Common Name mandatory for digital certificates?

I'm working on a project, where we use the Common Name as a certificate's basic identifier. However, importing certificates without the Common Name fails. What's the default way to use digital ...
8
votes
2answers
3k views

Why do embedded systems store server's public certificate in ROM?

In the home automation scenario, smart gateway can bridge the many smart devices with Internet. In many cases, a server's public certificate is stored in the embedded system's ROM during manufacturing....
8
votes
2answers
15k views

Is an AIA or CRL useful / required at the Root CA if that Root is used to cross certify another PKI?

Suppose I have several independent PKIs that are used Two internal PKIs: One with SHA1 support the other with Suite B algorithms. A partner who I trust and have a policy map with. Since both my ...
8
votes
2answers
4k views

ASN.1: ENUMERATED vs INTEGER

From the X.509 specs: CRLReason ::= ENUMERATED { unspecified (0), keyCompromise (1), cACompromise (2), affiliationChanged (3), ...
8
votes
4answers
2k views

Alternative to “web of trust”

Let's say I have an SMIME platform where I want to easily establish trust across the entire world for a particular purpose, for example for sharing valid financial information. I think that a ...
8
votes
3answers
956 views

Does the SSL encryption strength or validation level of a website really matter?

When looking to get an SSL certificate one is presented with a lot of options. For example lets take Network Solutions since they have a nice comparison chart. Immediately there seems to be 4 major ...
8
votes
1answer
1k views

How to use encryption on a site that only uses an IP address, no domain name?

You can use SSL/TLS certificates and etc. on sites with domain names, but I don't know if it's possible to use them for IP addresses. If this is the case, would I have to use a self-signed cert and ...
8
votes
3answers
13k views

How do I produce a CA signed public key?

I have a need to have somebody else encrypt secret data with my public key that I can then decrypt with my private key. I have produced an RSA private/public key pair with OpenSSL gave them the public ...
8
votes
2answers
4k views

Did scammers take control of a subdomain to host phishing site?

This morning I received a text message (ostensibly) from my bank: We need to contact you. Please visit https://paymentassistance.nationwide.co.uk for more information My spidey sense immediately ...
8
votes
1answer
4k 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 ...
8
votes
3answers
2k views

Can my school see exactly what I’m doing? [duplicate]

My school requires us to install digicert global root CA and digicert sha2 secure server to access to the secure and guest WiFi onto our personal devices. Does this mean that the school can see the ...
8
votes
2answers
2k views

How can I verify that a root certificate is authentic?

I have found that my home PC (Windows 10) currently has 39 root certificates installed. While scrolling though the list I have noticed: Names that look familiar (e.g. Thawte / VeriSign) Names that ...
8
votes
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 ?
8
votes
2answers
2k views

How do systems protect against a stolen code-signing certificate after the certificate expires?

Imagine this scenario: 1st December 2014 - a certificate is stolen and used to sign malware with 2014-12-01 timestamp. 15th December 2014 - the certificate is revoked. Malware will be prevented from ...
8
votes
1answer
558 views

distributing files to VPN partners

suppose i've created VPN certificates for a certain VPN-RoadWarrior-Client, expressed in the files VPN-RoadWarrior-Client.key and VPN-RoadWarrior-Client.crt*, however VPN-RoadWarrior-Client is ...
8
votes
3answers
343 views

What kind of certificate should I get If I want to secure a connection between a web server and a database?

I know people buy SSL certificates to secure their sites. What kind of certificate should I get if I want to encrypt a connection between an application server and a database? Application server may ...
8
votes
1answer
1k views

Is there an official standard and/or name for PEM certificate bundles?

This is a question that's not really about security proper. It's about security/crypto nomenclature. It's been bugging me a bit, so here goes: I know two approaches for bundling related certificates/...
8
votes
2answers
11k views

Android Kitkat reports: “Network May Be Monitored by an Unknown Third Party” when using non-default root CA

My company uses a private PKI to handle such scenarios such as Mutual auth (TLS) to a website using client certificates SSL web server certificates on an Intranet (once a VPN session is established.) ...
8
votes
1answer
884 views

How can I verify if a website revoked its old SSL certificate keys? [duplicate]

Through reading from multiple sources and watching Security Now's How the Heartbleeds, I have come to the understanding that the following procedure is recommended to be safe from the Heartbleed ...
8
votes
1answer
298 views

Browser blacklists & the Symantec-Google Certification Debacle

Background: As explained e.g. on this Google company blog, Google writes that: On September 14, around 19:20 GMT, Symantec’s Thawte-branded CA issued an Extended Validation (EV) pre-certificate ...
8
votes
6answers
2k views

Easy explanation of SSL client certificates for a developer

I've been thinking about using client certificates for my web apps, desperately hoping for security-conscious users to put their private key on HSMs so they don't get stolen even if the machine is ...
8
votes
1answer
2k views

Moving from a one tier to a two tier Microsoft Certificate Authority hierachy

Right now we have a single Microsoft Enterprise Root CA which issues certificates to our VPN users for two factor authentication. We're planning to extend use of the CA to issue certificates for RDP ...
8
votes
2answers
5k views

What is the best strategy to store and share pem files between team?

Our company's small tech team works with several different servers, to which we connect with pem files. What is a good way of storing the pem files so that it can be accessed by other team members if ...
8
votes
2answers
2k views

Where are the anonymous/private domain validation SSL certs?

I have yet to find a CA that doesn't require personal information for DV certificates. Is this because all of the major browsers and operating systems have a policy to reject CAs that don't require ...
8
votes
1answer
156 views

What considerations should apply for self service Renewing, Revoking, or Unrevoking a certificate?

I need to design a self service portal for renewing, revoking, and unrevoking a certificate and have come up with the following rules*: Renewal Certificates have a short term validity and need to ...
8
votes
1answer
773 views

Installing a CA only for specific domains

For many reasons, it's often convenient for organizations to have their own CA (self-signed or otherwise). As I understand it, adding the CA certificate to a OS or browser will make it trust the ...
8
votes
1answer
186 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 ...
8
votes
1answer
5k 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-...
7
votes
6answers
2k views

Should the bit-strength selection of a child certificate be influenced by the CA or the chain?

All things being equal; suppose I have a CA chain that has 1024 bits of RSA encryption. Does this mean that my selection of a child CA or WebServer certificate gains no benefit from a higher level of ...
7
votes
3answers
7k views

Is it required to have the same Domain Name and Common Name for SSL Certificate?

I have an SSL cert in which CN is "abc.xyz.com". But the url shared to 3rd party organization to access a web app on our server is: "def.stu.com/what-ever". When this arrangement is working for ...
7
votes
4answers
4k views

How to prove Bob has received Alice message

I have read up on Digital signature and it is stated that it provides non-repudation. Assuming Alice signs the message using her private key and sends it to Bob, Bob can use Alice's public key to ...
7
votes
2answers
4k views

Getting self-signed SSL certificates for all https connections made from some premises

Context: I'm currently working as an expat for my company in a country where the Internet is notably untrustworthy. It made the headlines a few months ago for stealing facebook, twitter and gmail ...
7
votes
1answer
2k views

What's keeping a malicious man in the middle server from forging a valid certificate

According to process of authenticating a server certificate: What's keeping a malicious server to fill up a valid server certificate since it knows all the things: Forged Server public key (man in ...
7
votes
3answers
880 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
votes
2answers
22k views

OpenSSL, x509: what's the significance of CN (Common Name)?

With regard to these three items Certificate Authorities (CA) Gateway certificates End-point Certificates (client-cert) What is the significance of the Common Name CN with regard to the a VPN? Does ...