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10

So we had to install their root certificate "PrivateCompany Root CA" to our web server. Why? Globally trusted CAs are useful in general purpose clients like browsers. But if you consume specific web services from a custom client you can add that CA locally. Every decent SSL client allows you to influence certificate validation. For example by ...


9

TL;DR Anyone can send a message and say it is from Alice if it is not signed; there is no way for Alice to prove that she didn't send those unsigned messages. However, Alice can prove she sent a message by signing it with a private key. Similarly, anyone can say Bob read a message, and Bob can't prove he didn't. But Bob can prove he read a message by signing ...


8

In practice, unless Bob sends a signed receipt, you are out of luck. The underlying cryptographic problem is called fair exchange. If you consider a network protocol such that Alice and Bob want to send each other some data elements (e.g. in your case an email from Alice to Bob, and a receipt from Bob to Alice; but it also works as a model for payments), ...


6

There is only full trust with the CAs you've installed. This means, that there is no restriction which certificates a trusted CA can sign. So it can also sign fake certificates for sites they don't own (e.g. banking.com) and you will accept them. I don't know how you communicate with the partner, but with languages like Perl, Python etc you can specify a CA ...


6

You've evolved to mostly right, but to add several points and expand on @CoverosGene more than I felt comfortable doing in an edit: X.509 defines a certificate (and some other things not relevant here) in ASN.1, a (very!) general data structuring method which has several defined encodings, of which DER Distinguished Encoding Representation is quite common ...


4

You can have SSL/TLS without certificates. This is supported in the TLS standard: the "DH_anon" cipher suites involve no certificate whatsoever. But you have to remember that such an unauthenticated TLS is inherently weak against active attackers, since they cannot prevent client or server impersonation (or both at the same time, which is called a ...


4

SSL/TLS (the underlying protocol for HTTPS) provides two features: Encryption, so that nobody could passively listen to the data. Encryption is done using a key which is somehow shared between the peers. Identification, so that you can be sure who you are talking to. This is usually done with certificates. While you might have encryption without ...


4

Guess My educated guess from reading the spec: The browser will never see more than one server-certificate. Rather the cipher spec is negotiated in advance. And ONLY THEN does the server send the certificates. So if negotiation winds up with an an RSA-cert authenticated cipher suite, then the RSA cert chain will be sent. And if the negotiation winds up with ...


4

Fiddler captures HTTPS traffic by generating on-the-fly a fake certificate for the intended server, thereby running a complete Man-in-the-Middle attack. This requires that the client is configured to accept the Fiddler-controlled CA as a trusted CA, as described in the documentation. This kind of interception breaks client certificates. When there is a ...


3

If you want to require Bob to let Alice know whenever Bob has received a message, as far as I know there isn't any such system built into the most common cryptographic systems. You would need to go outside of cryptography for a bit and require a server which tracks every time a message is downloaded from it. For instance, Alice could send a secret URL to ...


3

Key identifiers are extensions meant to help with certificate path building, but a mismatch does not imply a validation failure (at least as far as X.509 / RFC 5280 is concerned -- what implementations do is another matter). However, the subject/issuer DN must match in a valid chain, and a mismatch implies immediate rejection. If you have a certificate ...


2

I did some further investigation and realized that this constraint is taken into account at the time of resolving the certificate chain of trust, not at the time of creating a new link. From RFC 5280: The pathLenConstraint field [...]. In this case, it gives the maximum number of non-self-issued intermediate certificates that may follow this ...


2

If Charles proxy is able to intercept SSL/TLS traffic, then certificate validation has failed. This demonstrates that the mobile device is not properly verifying the server's certificate. In a mobile security assessment, certificate pinning can be disabled by hooking the platform's SSL/TLS implementation and changing how certificate validation works. An ...


2

Any self-verification mechanism included in the executable file could be replaced or removed by the attacker who intercepts the file. Therefore, we must leave signature verification to a system external to the downloaded executable, for example, the operating system. There are three possible outcomes such a verification system can produce: The signature ...


2

Not only will they not issue new certificates for unvalidatable IPs, but also revoke them in 2016. https://www.digicert.com/internal-names.htm As from 1 October 2016, CAs shall revoke all unexpired Certificates. More info in Mozilla's Wiki: CA:Problematic_Practices#Certificates_referencing_hostnames_or_private_IP_addresses


2

For public IP it must be checked that the IP is actually owned by the one who requests the certificate. Issuing certificates for private (reserved) IP is deprecated because obviously the ownership cannot be checked. For more information see CA baseline requirements Sect 9.2.1.


1

While there doesn't appear to be any existing privacy-friendly CAs at this moment, all evidence suggests that the recently-announced Let's Encrypt CA (launching summer 2015) will not require users to provide personal information. This could change, but I doubt it will given EFF's involvement. If Let's Encrypt will not collect any personal information when ...


1

PKCS #7 can be thought of as a format that allows multiple certificates to be bundled together, either DER- or PEM- encoded, and may include certificates and certificate revocation lists (CRLs). Per RFC2315, PKCS#7 is a general syntax for data that may have cryptography applied to it, such as digital signatures and digital envelopes. The syntax admits ...


1

Because verification is up to clients. And some of these didn't do a good job. So to support these you had to fiddle with the certificates. MichaelHolm.Info: IP addresses in SubjectAltName in SSL website certificates #fail for some browsers


1

Why do CSR utilities give you the option to list an IP as an IP if this does not work? I don't know which CSR utilities you refer too, but some of them target people who know what they do. Certificates are not restricted to browsers and the rules how they get used differ in other contexts. Especially the often used openssl is a tool which is able to ...


1

In SSL/TLS, the server is supposed to send not only its certificate, but a complete chain that goes from the root to the server's certificate (the root itself may be omitted, but the intermediate CA should be sent). If the server does not send a complete chain, then it is up to the client to try to complete it, e.g. by downloading the missing certificate, ...


1

The question is, assuming you've decided which CA's (Certificate Authorities) to trust, how do you get their certs. If you trust "Starfield Services Root Certificate Authority - G2" and you want to know if you should trust the hypothetical ""Starfield Services Root Certificate Authority - G3" (for example), you do have to "get it from the horse's mouth" as ...


1

Sounds to me like you looking more at the integrity of the actual file or data. When it comes to checking to ensure it is not infested with a possible virus, that where your Antivirus comes into play, or a UTM on your Firewall. For instance; a Sonicwall Firewall appliance would be able to ensure the safety of that file. but the actual integrity of the file ...


1

Windows manages certificates and private keys separately. Each certificate may point to a private key; several certificates can point to the same key. Each such "pointer" is given as the name of the Cryptographic Service Provider (that morally contains the key), and the key name within that CSP. Windows does not keep track of how many certificates point to a ...


1

This is a security feature called certificate pinning (or public key pinning). In this case the browser knows which certificate (or public key) to expect and refuses any attempts to override it by the user. Twitter is included for public key pinning since Firefox 32. See https://wiki.mozilla.org/SecurityEngineering/Public_Key_Pinning for more details.


1

There are not much details about your certificate itself, but I assume that you are connecting to an IP address and you are trying to use the IP address as the common name inside the certificate. As far as I know this is not supported by Safari. Instead it requires the IP addresses to be specified inside the SAN section (subject alternative names) of the ...


1

When you create the Certificate Signing Request, you simply need to specify what level of encryption you desire. For example, for 2048-bit: openssl req -new -newkey rsa:2048 -nodes -out Test.csr -keyout Test.key There are a bunch of tools here that will tell you what command to use based on your Operating System and requirements: ...


1

As far as other Certificate Authority (CA) root certificates security is concern, then there are no issues expect if you are going to implement an authorized Certificate Authority SSL certificate. If the security certificate is from Trusted Certificate authority then it never cause any security trouble.


1

To some extent what the company can do is limited to The Name Constraints (if any are applied) The Enhanced Key Usages (if any are applied) Of course this depends on client software properly validating each and every intermediate certificate in the chain, up to and including the root. It's possible that some client software doesn't validate the chain ...



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