New answers tagged

14

Yes, the number of compromised certificates are much larger with Root Certificate compromise. But it's not just the number certificates. Getting a new root certificates deployed due to compromised root is massively more difficult than replacing the certificates whose intermediates are compromised. For starters, replacing Root Certificate of a public CA, ...


10

Is that correct? Is there another benefit? An offline Root CA sacrifices convenience to gain security. But, anyway, CA must issue new Intermediate CA certificates and revoke the old ones... so the only benefit that I can find is that CA issue different Intermediate certificate for different purposes. Yes, in case of a compromised Intermediate, ...


3

So the "universe" of compromised certificates is smaller that if Root CA would have signed all of the certificates. Sure, you could put it that way. But until the intermediate CA has it's certificate revoked (and even after that, it could still be problematic), it could continue to create bad certificates that users will trust. Because revocation isn't ...


2

What you are looking for is to modify the certificate in a way that it contains the ability to be a CA, i.e. set the CA flag to true. Fortunately you cannot simply modify a certificate, because any kind of modification invalidates the signature and thus nobody will trust this certificate anymore. This is essential because otherwise everybody could just ...


1

You can't do this, you will have to apply for a new certificate. There are special types of certificates that apply for multiple previously specified domains at once.


0

Windows Environments. Background Windows servers that have internet connectivity reach out to CA servers and automatically update Trusted Root Authority certs, CTL, STL and Revoked certificates. This occurs in the background and requires zero input or interaction from the user. Why control it? Many government environments like to shut this setting off as ...


4

Does the term "certificate authority" refer to the organization issuing certificates (symantec, comodo, let's encrypt, ...) Technically, yes. or to the device and software that issues certificates from CSRs or both? In practice, yes. A Certification Authority (CA) is defined as follows by RFC 5280: Following is a simplified view of the ...


8

When speaking about a trustworthy "Certificate Authority", we refer to the organization/entity issuing the certificates, and not the tool used to generate them. It refers to the entity in the "Issuer/Issued by" field of your certificate (e.g. DigiCert for this website). Thus, if you issued your own certificates using the same tools as DigiCert, say OpenSSL, ...


7

By having the file, it would be possible to try to brute force the password, so you would need to choose a really strong password to protect it and make brute forcing infeasible. Eg I can find on google tools that claim to brute force PKCS#12 at 500k passwords per second. If you choose 8 random printable characters it would take more than 400years. That on a ...


1

How does EV green extended validation SSL certificate affects the speed of my web site (if at all) comparing to a regular SSL? EV SSL certificate doesn’t affect on website loading speed and works same as non-EV SSL certificate. In fact all SSL certificates come with same 256-bit encryption and 2048-bit root key encryption, but there are difference ...


0

You can solve this by using deployment tools such as Chef or Ansible. Particularly about Chef, you have the Chef Push to push whatever cookbook (i.e. the key files) to all the nodes (i.e. the servers).


1

Convention today is two use 2048 bit RSA for standard certs. If you want to be extra safe (e.g. NSA Suite B) use 3072. Assuming everything else is secure (big if) larger is safer, but introduces issues of performance (larger is also slower and the speed decrease is not linear) and larger is sometimes not compatible.


4

"Anything may be crackable given enough time and resources." Here is a good article that explains the differences of key size. Now imagine you exaggerate and create a 8192 key can it be cracked? Likely not. Are you safe? This all depends on the security of the system. If someone can compromise your machine and steal the key you made, the encryption ...


1

The website operator is responsible for notifying the CA to revoke the certificate, and would usually reissue a new Certificate at the same time. The CA is then responsible for publishing this information through CRL and/or OCSP. The client application is responsible in fetching the CRL/OCSP status of a Certificate from the CA. In some rare cases, the CA ...


1

How does EV green extended validation SSL certificate affects the speed of my web site (if at all) comparing to a regular SSL? None at all. EV certificates are technically the same as regular certificates with just a different OID policy number (so browsers can differentiate EV certificates). The main difference for EV is in the identity verification ...


3

Is EV green extended validation slower than a regular SSL? A EV certificates is just a normal certificate but with a few special issuer specific X509 extensions. The browser compares these extensions against the extensions expected for EV certificates on the issuers CA and if they match it will show the green EV bar. These special X509 extension are not ...


1

AFAIK, EV is just a bureaucratic stuff, requiring you to have a physical location, registered name and other things that identify you. But then, the certificate is the same, so there is no decrease in the performance compared to a regular DV certificate.


0

Yes. Note that providing more than one certificate is common amongst servers to enable TLS connections with different parameters. A server chooses and sends one of its certificates with respect to: CipherSuite list sent by client in Client Hello Message. For example, if the server wants to negotiate on the cipher TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 then, ...


0

Yes, you can have more than one trusted certificate path on a single server. Regarding your concern, please note that certification path does not refer to certifying the server certificate, but its public key, therefore certification path might consist of one self-signed certificate only. Speaking of server providing two self-signed certificates is ...


0

There is probably a more elegant way to do it, but I add the following option to the [ v3_ca ] section of my OpenSSL configuration file: certificatePolicies = 2.5.29.32.0 The OID values are available at http://www.alvestrand.no/objectid/2.5.29.32.0.html .


25

The answer by user2320464 is good, but I'd like to expand more. Summary: The certificate holder generally does not manage their own revocation information, because the whole point of revocation is to announce that holder of this certificate is not trustworthy. The rightful owner of the cert needs to be able to declare the cert Revoked, but in a way that ...


5

Typically certificates are revoked by the person being issued the certificate. So if you were to purchase an SSL certificate and later found the private key was compromised, then you would revoke the certificate. This action would be recorded on the "Issuing CA" where the serial number of the newly revoked certificate would appear in the Certificate ...


2

It is the responsibility of the person who bought the certificates to ensure the security of the cert. It is the responsibility of the CA to revoke any certificates that were sighted breaching the terms of service. A certificate is a lot like a driver's license. If someone steals it, you have to report it.


2

Since there is no way to cryptographically invalidate a certificate, a system must be used to publicly announce the revocation of a certificate. The Online Certificate Status Protocol (OCSP) is the current way of doing this. Browsers can check an OCSP provider to confirm that a certificate is not revoked before connecting to a website.


2

If I understand your scenario correctly: You're talking about a security mechanism that relies on signatures made by 1024-bit RSA keys. You have a relatively easy way of deploying updated certificates and revoking the old ones. It's a matter of days, maybe months, but certainly not years. The public record for breaking RSA is a 768-bit key. Nation-states ...


1

First and foremost, Qualys probably alerts you because as of January 1, 2014 the Certification Authority/Browser (CA/B) Forum required that certificates issued after this time frame MUST be at least 2048-bit key length. The answer to your question comes down to a administrative decision about what risk the company is willing to take/assume. Starting with ...


0

As a (nother) addendum to StackzOfZtuff and dr jimbob's answer's the Adi Shamir et al. paper Playing hide and seek with stored keys takes a very different approach, than looking for headers The Shamir approach relies on comparing blocks of data in the complete memory string (i.e. dump the entire contents of memory / disk as a string) and seeing if they ...


2

As an addendum to dr jimbob's answer: There are utilities that look for these patterns and try to extract keys that way. Disclaimer: I have not tried any of these utilities. This post is just a nicer version of the links posted by user "void-star" on HN. (See below.) Whitepapers about the general idea: Adi Shamir and Nicko van Someren, 1998-09-22, ...


0

Assuming the source of the new certificate is the one you're pinning, and the pinning certificate hasn't been revoked, you're probably OK. At some level, you have to trust the system, and you're already doing more than most TLS clients bother with to verify the server. Now, with that said, standard practice is to pin only the public key information (which ...


3

TLDR: in limited cases yes, but don't First, key-exchange and authentication aren't really independent in SSL/TLS. Although there are sometimes a few choices available, many combinations you could reasonably choose do not exist as ciphersuites. (Unlike for example SSH, where the pieces are negotiated separately and you can get any combination as long as ...


1

Your question about when / how to renew the CA key is a good one, but I'm afraid that it doesn't have a generic answer; it depends on which applications are consuming those certificates and how they expect a CA to behave as it approaches its end-of-life. One thing that is universally true is that end-entity certs should never outlive any CA in their issuing ...


1

Five years is a long time in Information Security. Ten years will see the security world decide that some algorithms and keys are too easily compromised. I have a client who had implemented SHA1 hashes in each tier in order to support unpatched Windows XP using a PKI environment that was built within the last four years. We had to rehash each CA's ...


5

A TLS cipher consists of a part defining the authentication of the certificate (i.e. ECDSA, RSA...), a part defining the key exchange (ECDHE, DHE...) and a part about the kind of symmetric encryption and the associated HMAC, i.e. RC4+SHA1, AES128+SHA256 etc. From these parts only the authentication part depends on the type of certificate and everything ...


3

Update in response to your edits in the question You are correct that validating a cert up to the trusted root is not 100% foolproof. What it guarantees that a trusted CA issued this cert to the domain that you are communicating with (because you can check that the URL in the cert matches the URL that you are establishing the SSL connection with). This was ...


1

From the Wireshark trace on B2, we see that the client is simply not responding at all; after one minute, the server grows impatient and closes the connection. This is probably not a problem of certificate availability on B2: if SChannel simply believed that it had no appropriate certificate, then it would send back an empty Certificate handshake message. ...


6

This is an awesome idea - to manually trace through the cert validation process! I've enjoyed reading through your steps, since I've never actually done it myself! Answering your questions: First question: Is this the correct way of obtaining the certificate the *.wikipedia.org certificate was signed with? After all, how can I be sure ẁikipedia.org didn'...


3

Snapchat used to use a famously weak crypto implementation with a global key stored in the source code to encrypt pictures at rest, so they are infamous when it comes to security. But, luckily enough, all communication is over HTTPS. That means the owner of the network (your company) can not MitM the users (your friend) and read the content of their ...


4

The way certificates work is that a certificate is sent by the web site to your computer. Your browser reads the certificate, looking for the identity of the "signing certificate." It then validates the signature of the downloaded certificate was created by the signing certificate. If the signing certificate is signed by itself, it is called a trusted ...


15

Browsers do not accept verification from just any third party; if they did the whole exercise would indeed be pointless. In order to be accepted as valid, the certificate presented by the website must be digitally signed by a trusted certificate authority. The default list of trusted certificate authorities, which you can see in Chrome by going to Settings-&...


2

You are correct on your first statement. Unless s/he is a trusted CA, your browser will still bitch that the cert is not trusted. And you'll know you're being MiTM'd. For the second paragraph, you're reaching a bit.The hacker would have to compromise DNS for ALL CAs and have a way to validate the bogus certs. Highly unlikely.


0

Never install a certificate you don't trust. If you trust a certificate, the company/ person that issued the cert can mitm (and certainly will) any https connection you make. The system is often used by companies to monitor their employees activities. Would you accept that for your personal data ? I think not...


3

So is it a 256bit SSL cert? No. Yes. Maybe. The real answer is: It depends on the terminology, as some CAs appear to be notoriously lousy about such details. The certificate contains the public portion of the asymmetric key pair that is used to authenticate the server (ensure that you really are talking to the server you think you are talking to) and ...


5

First off, let's be careful about language, when you talk about a public CA like Entrust, or Verisign, or Digicert, yes there is some software involved for actually creating and managing the certificates, but you're really talking about the people. These companies are trusted CAs not because of the software they use, but because their network admins take ...


-1

To answer the last part. Yes they are all compliant with x.509. And they can all be used to set up a certificate authority (as described by previous answer). There are functional differences, more on the management, scalability or specific technical features, side that makes one or the other of them more suitable for your requirements than the other.


7

So is it a 256bit SSL cert? No. There are several aspects which are relevant for a certificate: the type of the key, usually RSA or ECC the size of the key. The strength of the key depends both on the type and the size, i.e. the commonly used 2048 bit RSA and 256 bit ECC keys are roughly equivalent the signature algorithm, i.e. SHA-256 + RSA When ...


0

It sounds like you need to build some Public Key Infrastructure (PKI) into your enterprise. I'm assuming the WCF server and the client machines are internal, meaning that you can use internally signed certificates using your own Certificate Authority (CA). Once you've set up your "root CA" for the enterprise, you can create intermediary CAs to handle ...


0

The four possible key "usages" are Certification: signing other keys Signing: signing data Encryption: decrypting data Authentication: signing authentication tokens When you look at your key using --edit-key, you find the usage listed behind each key and subkey. By default, all that are supported by the key type are attached to the master key (so, RSA ...


2

In case of cacert.org, they are presenting a self-signed certificate and that's why your browser complains. There is no trust chain that leads from the certificate to a root CA that you trust. If you were using a Linux distribution that comes with their certificate pre-installed, you wouldn't see a warning. It would be inferred that by using such a system ...


1

Use cmd: NET USE (to see what you're connected to) NET USE * /DELETE (to delete all connections) net use info is not the same info as listed in keymgr or credential mgr.


0

I would like to add that while the technology is the same with 256 bit encryption, you are also paying for the following factors: Level of validation - this is the amount of checks that the issuer will do to verify your company or website Number of domains - how many domains this certificate will be valid for Trust level - as members mentioned above, you ...



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