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43

You are right assuming the certificate is useless without the private key, so sending it in the mail is no big security risk and is common practice actually. The certificate is supposed to be public, connecting to your website would also provide me with your certificate, so no need to hack your email there. edit When starting the connection the server ...


29

Yes, what you are getting in the zip file is exactly what every visitor to your site would get every time they start a TLS session - the public keys with certifying information. The private key is the only thing that should be kept hidden from unauthorized access.


28

A CA is supposed to make sure that the certificates it issues contain only truthful information. How they do that is their business; serious CA are supposed to publish detailed "Certification Practice Statements" that document their procedures. In practice, when you want to buy a certificate for a www.myshop.com domain, the CA "challenges" you, so that you ...


12

Certificate Authorities make a living based on their reputation of only giving out certs to the rightful admins of a domain. If a CA starts giving out too many fraudulent certs, the browsers will pull out their root cert and the CA goes bankrupt, so it's in the CA's best interest not to do this. Exactly how a CA verifies the identity of the applicant varies ...


6

How exactly is this protecting against a malicious DNS routing? Not at all. If an evil guy has a valid certificate (e.g. from a hacking a CA) and then manages to man-in-the-middle you, then your connection is hacked. I was expecting a challenge response using the public key of the server, but I cannot find it. In order to do this you would have ...


5

When you visit https://security.stackexchange.com/, in some instances you'll be served content (ads specifically, it appears) that is over http rather than https. Most modern browsers will warn when this happens as you are seeing. The risks are that the content that is served over non-TLS connections can be viewed and manipulated before reaching your ...


5

While prices differ they don't differ that much. You are comparing certificates from Symantec with support for multiple domains with single-domain certificates from Comodo. Once you try to use multiple domains with Comodo the price will be much higher. While Symantec is still more expensive Comodo is with around $2000 for 2 years not that much cheaper ...


5

As per X.509, no problem. You can mix algorithms at will. Each signature is independent. (X.509 includes a special provision for when a CA uses DSS and issues a certificate that also uses DSS with the same group parameters, in which case the issued certificate may omit the group parameters. This is called "parameter inheritance". This is never used in ...


5

Generally speaking, in the certificate request, these values do not matter. What matters is what appears in the resulting certificate, and the certificate contents will be chosen by the CA, not by you. The certificate request is a vessel to convey your public key to the CA; that request uses a format (normally PKCS#10) that includes a space of a "subject ...


5

In my browser (Chrome on Windows) I have certs for both of those CAs. I'm not entirely sure what your question is getting at (Why a CA would have more than one cert? Why a CA would issue off a non-root cert? Why OS X doesn't ship with the root cert?). If you could update your question with more detail, that would be great, but in the meantime I'll try to ...


5

how can they ensure that you are really an admin of this myshop.com, perhaps it was an attacker who requested this certificate to be able to perform man in the middle attack? They can't. If you can receive mail for admin@example.com then you can get a cert for that site. what prevents the same attacker from requesting the certificate for the same ...


4

SSL certificate price depends basically on how much the vendor feels he can charge for it. The per-certificate issuing cost is extremely small; most of it is about the manual operations to verify the identity of the requester, but that is still a lot less than what CA typically charge. Like with software, CA charge money to cover their development cost, ...


4

You are essentially correct in your last paragraph: Is the sole purpose for authentication purposes so that one who has a public key knows that this piece of encrypted hash information is signed by the person that issues this public key (has the private key) since he/she is able to decrypt it. Though, as mentioned in comments, and in various places ...


4

Yes, this is possible and it is often used in practice. The certificate is only bound to the private key and not to a machine. And the private key is not bound to machine too so you could take it to more machines. But you should be aware that the wider you propagate the private key the harder it will be to protect it. And without proper protection it might ...


4

There is a standard for exchanging messages with CA, but it is rarely implemented in practice. Existing commercial CA that deal with many remote customers tend to organize the certificate issuance process through some custom interface (often Web-based) and the certificate-sending is part of that process. Various methods are used in practice, possibly ...


4

In fact you are using the wrong public key to decode the signature. Being part of a PKI, the paypal certificate is signed by an issuer called "Symantec Class 3 EV SSL CA - G2". If you display the certificate with your browser, you should see it. You can find their public key in the certificate as well : ...


4

Here's how I would do that: Examine all the test descriptions from sites like badssl and Qualys SSL Server Test. Follow up on links to the actual issues being tested, read and understand the problems. Run Qualys against your server, capture the traffic using tcpdump, and examine the interactions as much as possible to understand what's going on. Set up ...


4

Since all of the other subquestions have been adequately answered, I will attempt to answer the question regarding registration of domains that are similar to the original. This action is known as typosquatting and since the typosquatter owns the domain, they will have complete control over the verification requests that the SSL certificate authority ...


3

It is not unexpected for enterprise networks to run web security proxies that inspect encrypted traffic when given a reason to suspect something problematic. This allows them to detect encrypted malware and prevent it from infecting you. (It also allows them to restrict other content, such as porn or some other policy enforcement that is not related to ...


3

From the description, one may infer that the attack works the following way (warning: I wrote "infer" and I mean it -- I have not tried it): The attacker is in position to intercept all network traffic from the victim (e.g. the attacker operates the WiFi access point to which the victim unwisely connected). The attacker owns (legitimately !) some domain, ...


3

The simple answer is no you can't have an RSA cert which has a ECC public key. By definition an RSA cert is a cert which has an RSA public key. The CA could sign your ECC cert with their RSA key but that wouldn't make it a RSA cert it would make it a ECC cert signed with an RSA key. Likewise a CA could sign a RSA cert with their ECC key but that wouldn't ...


3

Why are there two paths? Were do they come from, where are they configured? A signature is created by using the public key of the issuers certificate. Two certificates can contain the same public key (typical after re-issuing a certificate) and this leads to alternative trust path if both of these CA certificates are included in the trust store. ...


3

1 - The "trust store" depends of you browser / operating system. For Firefox, it's inside firefox, for Chrome on windows, it's the trust store of your windows There is two path because ssllabs know two certificate that can be root. If your visitor have any of the two in their trust store, your certificate will be valid. 2 - Chrome may complain because if a ...


3

So are there actually two different legitimate versions of the VeriSign certificate which can be used to sign the same child certificate? Signing is done by the public key in the certificate. Both certificates have the same public key, so both can be used to verify the signature. The difference is that 18:da:d1:9e:26:7d:... is issued by itself while ...


3

q1) Correct. Every message needs to be sent with its own signature. But if lots of information has to be sent this way, it is not very efficient because public key cryptography is rather slow. Usually the two parties would rather use a protocol allowing to share a secret, then use symmetric-key authentication, like a message authentication code (MAC). q2) ...


3

You can have different root certificates with different fingerprints which contain the same public key. This is actually not uncommon when you are in the process of replacing a root CA. See also Multiple Versions of Intermediate SSL Signing Certificate


3

Should wildcard certs be used? Generally not, and here's a good list of reasons why. Subject Alternative Name (SAN) certs provide most of the functionality without the same level of security drawbacks. Wildcards had turned mostly into a lazy shortcut for people who didn't care about security, which is why they're discouraged these days. Should wildcards ...


3

If there is a intercepting proxy between the web server and the client, mostly the proxy uses its own signed certificates which the client may or may not trust. Then why don't proxy just take the certificate from server and forward it to client so the client will trust it. Also if the private key is only held by the server, then how come an ...


3

You can display Subject Alternative Names (SANs) with OpenSSL like this: (I'm using the Facebook.com cert as an example.) Using the x509 subcommand: $ openssl x509 -in facebook-cert.pem.cer -noout -text | grep 'Subject Alternative Name' -A1 X509v3 Subject Alternative Name: DNS:*.facebook.com, DNS:facebook.com, DNS:*.fb.com, ...



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