Need to authenticate a server using certificate, I have used OpenSSL to generate certificate and it was able to authenticate with certificate by enabling client certificate authentication in IIS.
Now when I export the certificate from the device and tried to install it in the other device it was able to authenticate the server, is there any possible way to link or generate a certificate that will only work for the specific machine?
Yes - keep the private key private.
Moving a certificate by itself to another client won't let you authenticate as the owner of that certificate. You would have to move both the certificate and its corresponding private key.
There are generally two ways you can stop the private key being copied:
Use administrative controls to ensure nobody in your organisation copies the keys. This is usually in the form of an agreement between the certificate issuer and the entity named in the certificate, to the effect that "you shall not copy the private key!!". As you can imagine, depending on the scenario, this might not be that enforceable.
If the certificate is certifying a device, generate and store the private key in a hardware device that is a permanent fixture in that client device. A Trusted Platform Module is an example of a device fitted in most modern end-user devices for this purpose.
If the certificate is certifying a person, generate and store the private key in a hardware device that is issued to that person. A smart-card is an example of such a device. You would probably also need administrative controls here to ensure that the user doesn't share their card with others and that they keep any PINs or other authentication data private.
Note that attempting to certify something like the DNS name of the client device as as unique identifier doesn't work, as DNS, MAC addresses etc. can be spoofed.
Related
ACME is used by some certificate authorities to process automated signing of certificate requests and issue resulting certificates.
An increasing number of applications (Eg Traefik) now have builtin support for ACME. This is very useful for managing certificate cycling without tracking where every deployed application stores its certificates.
However "free" certificates from letsencrypt and similar certificate authorities are not always appropriate for all applications. Such examples include some software requiring the exact same certificate being installed in multiple layers of an application's edge gateway (yes this does happen).
I'm wondering if, hypothetically, ACME v2 can be used to redistribute existing SSL certificates and associated private keys. Or is it only capable if responding to CSRs where the private key is never transferred between ACME server and client?
ACME is defined by RFC8555 currently.
There is nothing that prevents other CA to use it, besides Let's Encrypt, and indeed there are other CAs existing using it, and others adding it to their existing API.
The key associated to a certificate should never travel. The CA shouldn't know it. As such, there are no operations in ACME that would allow a CA to send the key, besides the certificate, and that is a good thing.
Retrieving a certificate is a core operation, see "7.4.2. Downloading the Certificate". It could happen separately/outside of a previous certificate request. The problem being then: how does the client know which URL to use to download a specific certificate (an information that it receives when doing the normal authorization/validation steps)?
There are other protocols to manage communication of cryptographic materials such as X509 certificates.
Still in ACME, you might be interested in RFC 8739 "Support for Short-Term, Automatically Renewed (STAR) Certificates in the Automated Certificate Management Environment (ACME)" which allows the CA to pre-generate certificates.
And the related RFC 9115 "An Automatic Certificate Management Environment (ACME) Profile for Generating Delegated Certificates",
Outside of ACME, but very similar, you have RFC 8894 "Simple Certificate Enrolment Protocol" (but still no transmission of private key).
But you are not clearly describing the problem you have around "redistribute existing SSL(sic) certificates and associated private keys". What else do you really need besides an URL that gives back that data if it is that you want to send back to client (but again: making the private key travel is, in general, a bad idea)? Is authenticating the client the problem? Discoverability of the URL to use to download a specific certificate/key?
I am tring to figure out how a secure connection between client and server is established. I tried the SSL example provided by boost::asio library. My question is about the certifacte used by client and server. To be specific, I generated a private key(mykey.pem). Then I used this private key to generate a self-signed certificate(mycert.pem) and I used these files as follow:
Server side:
1)context_.use_certificate_chain_file("mycert.pem", error);
context_.use_private_key_file("mykey.pem", boost::asio::ssl::context::pem, error);
context_.use_tmp_dh_file("dHParam.pem",error);
Client side:
2)ctx.load_verify_file("mycert.pem",error);
With this code the handshake is done perfectly. My question is that how come both the server and client use the same certificate ("mycert.pem") in commands 1 and 2? With this approach a client can pretend to be a server easily.right? Do you think that I missed something here?
The certificate is public information.
It's the private key that allows the entity to prove its identity. The client is guaranteed by the SSL/TLS handshake that only the party with the private key matching the public key in the server certificate can be at the other end with the suitable master secret, so as to be able to decipher the communication. The problem it addresses is whether or not the remote party is indeed the one to which the certificate was issued. (This is similar to checking that the picture on the photo ID matches the person in front of you.)
Configuration of the certificate (and not the private key) on the client side is there to tell it which certificates you are willing to trust. The problem it addresses is whether or not to trust what the certificate say (in particular what it says about the identity of the server). This is normally done using a PKI, so as to build trust via 3rd parties (the CAs). (This is similar to checking that the photo ID itself is genuine, and that you can trust what it says.)
What you've done by trusting this specific server certificate is bypass the use of CAs to make an exception and indicate you were willing to trust this particular certificate to be genuine. (This is fine for a handful of certificates, but using a CA allows your trust structure to be more manageable and add other features, such as the ability to revoke certificates.)
I am developing an html application where an user has to first login using his digital certificate. After login he has to perform encryption and decryption of data using his digital certificate.
Now in case when the certificate is available in the form of .pfx file then we can just install it and the certificate appears in the container and we can use it during login and during encryption and decryption.
This works fine in case if we have .pfx for our digital certificate.
But now i want to enhance it for etoken's(security token). I dont know much about etoken's. The problem is that how can i use the digital certificate stored in it while login?
Also how should i use the private key stored in it while decryption?
Can anyone please tell me about any tutorials (if any) which will explain the usage of etoken and the CryptoAPI's.
As I mentioned in the answer to your previous question, Windows CSPs map the certificate from hardware to Windows certificate storage, so this is transparent to you. If you can access the certificate via Windows certificate storage API, then you don't need to care where the certificate is actually located.
Note that you can't transfer a private key to the server, i.e. you would have to use a client-side module (either ActiveX or Java applet) that will perform operations locally. This is not specific to certificates on hardware, but also to certificates which have non-exportable private keys.
I'm implementing a client with python's twisted that checks the server ssl certificate when connecting, following basically this recipe. I've seen in many HOWTOs such as this one the server checking the client's authenticity through a ssl certificate as well. Currently i authenticate my clients using an unique id and 1024 char string (they are automated clients without human interaction).
What I don't understand is what reason would I have to use the whole ssl thing for this instead of just sending the "password" to the server. After all the connection is already ssl encrypted, checking the server certificate and everything. This is a similar question but I want to know why people use ssl client certs and not just what is the best way to do it instead.
A client certificate restricts access to people authorized with certificates. Assuming your certificates are distributed and managed correctly, this makes it more difficult to connect from an unauthorized location (or say, a bot network), since you need more than just a username and password.
Client-side certificates are a potential part of a defense-in-depth strategy, if you are in an environment where you can manage client certificates.
Certificates are easy to revoke. Passwords can be stolen, but stealing a client side certificate would be much harder.
Using client certificate based mutual authentication prevents at least the following attacks/problems:
Phishing the password
Key logging the password
Shoulder surfing the password
Guessing the password
Password reuse on several services
Additionally, using client certs gives you the possibility to store client certificate (and the matching private key) on a smartcard, USB token or other hardware security module (HSM), thereby going from "something you know" (password) to "something you possess physically" (token, card) plus "something you know" (PIN). This is also called two-factor authentication.
In your specific case of using passwords as shared keys in a technical, system to system communication link, using certificates has two advantages:
scales better: with shared keys, every node has to share a different key/password with each other node, resulting in (n-1)! passwords, while with certificates, each node needs only one certificate and private key (n certificates plus a CA)
the possibility of storing the key on a HSM and thereby prevent it from being copied/stolen digitally.
The main advantage of client-side authentication (i.e. when server checks client certificate) is that if server gets compromised, the client's secret, which is private key for certificate, won't be compromised. Whereas if client uses credentials they could be compromised along with server.
Owning SSL certificates that are signed by a certificate authority means that the SSL certificate owners have gone through the hassle of being verified by the CA that the owner is who they say they are. For instance, if you have an ecommerce store called widgetsdeluxe.com and you have a certificate for the domain widgetsdeluxe.com that has been signed by Verisign, et. Al., shoppers will know that when they go to that site and the name on the certificate matches the actual domain name they went to, then they can trust that the information is secured and is coming from the widgetsdeluxe.com domain (this is to prevent spoofing and man-in-the-middle attacks).
My use case is very simple : I have a GUI application, and inside this application I host a service however clients of this services must be able to authenticate with UserName safely (The only thing I want is to encrypt messages to be sure that nobody can sniff to retrieve password of clients, I don't care about more security).
So, I want to ship a certificate with my GUI application and that my host (which is inside the GUI application... I know it's a little dirty) use the certificate to encrypt messages.
So my question is : Does my requirements oblige me to install the certificate inside the store on the host machine ?
Am I obliged to generate a new certificate with makecert for every host ?
What is the easiest way to deploy my application ?
(I control the client application so the validation of the certificate is not a problem)
First of all you should not use makecert to generate production certificates.
You could store the certificate in code and not in the machine but keep in mind that the security of the whole encryption is as good as the security of the certificate's private key. If the machine where the application will be run is secure you could use the certificate "incode" but if you cannot guarantee the security of the host machie you should install the certificate in Windows Store. Make sure the user running the application has permissions to read the certificate's private key.
If using WSE or WCF make sure you test the default message or transport encryption methods provided to see if they are good enough for your use.
Here is some references for installing certificate with private key (.pfx file) programmaticly.