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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18
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2answers
17k views

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. ...
18
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4answers
12k views

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 ...
18
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1answer
16k views

What is the actual value of a certificate fingerprint?

In a x509 digital certificate there is a "certificate fingerprint" section. It contains md5, sha1 and sha256. How are these obtained, and during the SSL connection, how are these values checked for?
17
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4answers
4k views

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 ...
17
votes
2answers
2k views

How can you prevent employees of your company from creating valid ssl certs? [duplicate]

When registering for an SSL cert, I was able to validate that I "owned" the domain I was creating the cert for by having a valid @domain.com email address. If I worked for a large company, say ...
17
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7answers
10k views

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 ...
17
votes
3answers
2k views

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, ...
17
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1answer
33k views

Can a CSR be created in OpenSSL with SHA2?

Can a CSR be created in OpenSSL with SHA2? If so, what would the command be and what does this tell the CA, if anything? If you could create a CSR using SHA2 would it "tell" the signing CA to use it ...
16
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3answers
3k views

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 webservices (over TLS/SSL). For security, we use Certificate Revocation List checking (or ...
16
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4answers
5k views

Why can SSL certificates not be free of charge?

I am a newbie in this field. I am confused with why SSL certificates cannot be free of charge. In my understanding the certificate is just a text file consisting of cryptic numbers installed on a ...
16
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2answers
1k views

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 ...
16
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5answers
4k views

Are self-signed certificates actually more secure than CA signed certificates now?

Are self-signed certificates actually more secure than CA signed certificates now? I ask this because recent leaks about the NSA spy programs and the secret FISA courts mean that the US government ...
16
votes
2answers
7k views

What are the advantages of EV Certificate?

What are the various advantages of using extended validation (EV) certificates than normal certificates which also provide comparatively high degree of encryption like RC4, 128 Bit? I know that the ...
15
votes
3answers
2k views

Multi-tenancy, SSL Certificates, and Subject Alternative Name

The X509 specification allows a CA to issue a single certificate for multiple hostnames, by using the "Subject Alternative Name" extension. From the spec: The subject alternative name ...
15
votes
1answer
3k views

REST specific security weaknesses

I need to start working with RESTfull Web Services. SOAP based web services have already so many standards to secure communication, establish trust etc. I am not aware of any for REST. What I would ...
14
votes
4answers
1k views

Is my Company Tracking Me?

Every time I try to connect to a site through HTTPS from my office computer, there is a Certificate Error thrown 2-3 times before showing the login screen. Till now I use to ignore this and click ...
14
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3answers
3k views

Can a wildcard SSL certificate be issued for a second level domain?

Something like *.com or *.net? How about *.edu.au? The RFC 2818 does not say anything about this topic.
14
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1answer
2k views

PayPal encrypted with obsolete cryptography

My Chrome just complained from PayPal's security, similarly to this issue: Google Chrome "Your connection to website is encrypted with obsolete cryptography" The identity is verified, but ...
14
votes
3answers
256 views

Domain name expiration and TLS

If I purchase a domain name that has expired, do I have any assurance that the previous owner does not have a valid HTTPS certificate for the site? In other words, do CAs check domain name expiration ...
14
votes
2answers
2k views

SSL fingerprint inconsistency: what does it mean?

I apologize if this is not the best place to ask my question on the stackexchange network, I couldn't figure out where to get enough attention and be relevant. Facebook provides a SSL host, it can be ...
14
votes
4answers
17k views

How are Chrome and Firefox validating SSL Certificates?

How are Chrome and Firefox validating SSL Certificates? Are they requesting data from an SSL certification website, like GeoTrust, to validate the certificate received from the web server?
13
votes
3answers
1k views

Trying to understand why signatures in root certs “are not used”?

Taken from here: Don't worry if the root certificate uses SHA1; signatures on roots are not used (and Chrome won't warn about them. Why are the signatures not used? Are not root certificates ...
13
votes
2answers
743 views

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 ...
13
votes
2answers
4k views

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 ...
13
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1answer
2k views

Renewing Microsoft Certificate Services Root Certificate

We currently have Microsoft Enterprise Certificate Server installed on a domain member machine which issues 1 year certificates to users for authenticating to VPN. We'd like to start issuing web ...
13
votes
2answers
4k views

Is Apple's push notification service implementation vulnerable to a MitM attack

Recently(more info) I've spotted a strange message in the logs on my quite recent, fresh installation of OS X Mavericks 10.9.2 Apr 27 15:26:47 Ivans-MacBook-Pro.local apsd[194]: Unrecognized leaf ...
12
votes
3answers
594 views

Incorrect use of HTTPS?

When I open https://java.com my browser says “untrusted connection” but when I open https://www.java.com my browser says it’s ok. But it's the same site. So my question is: Is this a security bug? ...
12
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5answers
2k views

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 ...
12
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5answers
5k views

Does HTTPS Everywhere defend me against sslsniff-like attacks?

http://www.thoughtcrime.org/software/sslsniff/ If I have a domain on my HTTPS Everywhere list, so that theoretically it could be only visited via an HTTPS connection in my Firefox, then could an ...
12
votes
2answers
2k views

Are there really functioning quantum computers?

I saw this video on youtube on quantum computing. It says that a company called dwavesys has already made commercially available quantum computer. I checked on the website and it exists. I thought ...
12
votes
4answers
22k 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 ...
12
votes
1answer
9k 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 ...
12
votes
3answers
2k views

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, ...
12
votes
4answers
2k views

Can real end-to-end SSL encryption be made?

I've read the various questions tagged [ssl] and [mitm] and [proxy] and I couldn't find a duplicate. I've got a very precise question but first I need to give some background. Basically I'm very ...
11
votes
5answers
2k views

Why is this certificate valid for so many domains?

If you look at the (invalid) certificate for https://i.imgur.com/ it says only valid for the following names: The certificate is only valid for the following names and then a list of about 100 names. ...
11
votes
4answers
1k views

Why isn't OCSP required by default in browsers?

According to the following screenshot, taken from firefox-3.6.17-1.fc14.i686, Firefox has an option to fail closed when unable to connect to OCSP servers. Can someone please explain why this isn't ...
11
votes
3answers
3k views

Difference between Certificate Authorities

I've been wondering for a long time about is. There are many certificate authorities having different types of certificates. But even certificates of the same security level cost a lot more with one ...
11
votes
3answers
15k views

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, ...
11
votes
1answer
9k views

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 ...
11
votes
4answers
2k views

Multiple CAs signing a single Cert/CSR?

Just saw this suggested on Slashdot So I've seen quite a few people wanting a switch to self-signed certs (who IMO mostly don't understand what making that secure actually involves), and an idea ...
11
votes
1answer
510 views

Is using a CA more secure if I'm self-signing anyway?

We have a web application that we run for clients at their booth on fairs. The communication between clients and the server was done over HTTP until recently. We're currently working on improving ...
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 ...
11
votes
1answer
515 views

Kaspersky Antivirus “secure connection scan” as broken as Superfish?

I've read a lot about Superfish (and similar ad-ware) lately and I basically understand the vulnerability to MITM attacks. But I'm actually wondering if the "secure connection scan" by Kaspersky ...
11
votes
1answer
156 views

How CA ensures that a certificate request is coming from me?

To establish trusted SSL connection I need to create a certificate request. For example, if I use openSSL I can do it by the following command: openssl req -new -key privkey.pem -out cert.csr ...
11
votes
2answers
9k views

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 ...
11
votes
1answer
281 views

Is TLS in Tor useless?

I am trying to optimize the Orchid Tor client library for my needs and noticed that every connection with every node uses TLS with turned off certificate verification. Actually there are no TLS ...
10
votes
2answers
973 views

How are digital certificates compared?

I have read about SSL and TLS; I know how RSA works and why digital certificates are necessary (more or less), but I am curious about how we prevent a fake digital certificate. The operating system ...
10
votes
3answers
4k views

How does an SSL server prove its identity?

This document says that a challenge response authentication proves the servers identity. But is a man in the middle attack still possible if the client does not verify domain name ? Please help me ...
10
votes
3answers
736 views

Can we make sure that the new Lavabit certificate is not under control of the FBI?

After the Lavabit shutdown, Ladar Levison (founder of Lavabit) announced that he’s "looking into setting up a site where users can download their data". Such a site is now online: ...
10
votes
4answers
3k views

HTTPS self signed certficiate for personal website

I want to make my Synology NAS accessible over the internet. When I create my own certificate and import this on all my devices (PC, Laptop, Smartphone, Tablet, etc.) is this as secure as buying a ...