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C# Connect to Ravendb keeps failing with error: This server requires client certificate for authentication, but none was provided by the client

No mather what i try, in an new .net 5 API project i cannot connect to RavenDB. It is given me an error:
This server requires client certificate for authentication, but none
was provided by the client.
The way I connect to the database:
byte[] certificateBytes = _certificateProvider.GetCertificate("CERT-NAME").Result;
string passphrase = _secretProvider.GetSecret("CERT-PASSPHRASE").Result;
X509Certificate2 certificate = new X509Certificate2(certificateBytes, passphrase);
var documentStore = new DocumentStore()
{
Urls = new[] { databaseOptions.DbUrl },
Conventions =
{
UseOptimisticConcurrency = true,
FindCollectionName = findCollectionName
},
Database = "DBNAME",
Certificate = certificate,
}.Initialize();
The certificate provider and the secret provider gets the data out of an Azure Key Vault. I validated the X509Certificate and it has the same thumbprint as I get in the admin panel of RavenDB. So that is loaded correctly. Also the certificate has the read/write rights on the requested database
But when i then do the following:
using (IAsyncDocumentSession session = documentStore.OpenAsyncSession())
{
var entity = await session.Query<EntityDTO>()
.SingleOrDefaultAsync();
}
Then i get the following error:
This server requires client certificate for authentication, but none
was provided by the client.
This while the certificate is given when initializing the document store. Anyone an idea how to continue with this as RavenCloud doesn't give more information then this?
In another project (.net core 3.1) the same code with the same certificate works. But could not find anything in the release notes of .net 5 what can cause this.

You need to load the certificate with the MachineKeySet flag.
X509Certificate2 certificate = new X509Certificate2(certificateBytes, passphrase, X509KeyStorageFlags.MachineKeySet);
This will solve the problem in Azure but your local dev machine might have a problem after this change. You need to allow full access for the user running RavenDB to the MachineKeySet folder on your local machine.
"C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys"
Please also note that if you don't dispose the certificate afterwards, the private keys pile up in that folder (a key is written to that folder every time the X509Certificate2 constructor opens the certificate).

In the RavenDB forum #iftah responded that you should set the storage flag to MachineKeySet because of the private key.
While that was not the case for me, it give me an direction to check. I was loading the certificate from Azure Key Vault using the CertificateClient and GetCertificateAsync. This only gives you the public key. So there never was an private key.
With the help of this post: KeyVault generated certificate with exportable private key. I've found out that i could use the SecretClient with GetSecretAsync. Then use Convert.FromBase64String() and that gives back also the private key.
So for the ones that have similar problems. Please verify when loading the certificate that you have the private key. My new code:
byte[] certificateBytes = Convert.FromBase64String(_secretProvider.GetSecret("CERT-NAME").Result);
X509Certificate2 certificate = new X509Certificate2(certificateBytes, string.Empty);
var documentStore = new DocumentStore()
{
Urls = new[] { databaseOptions.DbUrl },
Conventions =
{
UseOptimisticConcurrency = true,
FindCollectionName = findCollectionName
},
Database = "DBNAME",
Certificate = certificate,
}.Initialize();
And don't forget to load you certificate the following way if you want to have it working on Azure as #iftah suggested above:
X509Certificate2 certificate = new X509Certificate2(certificateBytes, string.Empty, X509KeyStorageFlags.MachineKeySet);

C# RestSharp Client Certificate getting exception "The SSL connection could not be established"

I programming in C# .Net Core 3.1 and .Net Standard library where this code is put.
I am not getting my http requests with RestSharp with a client certificate that are NOT installed on the server/computer i am not going to have access to the server/computer where this is going to be running later on..
My code:
// Create a RestSharp RestClient objhect with the base URL
var client = new RestClient(_baseAPIUrl);
// Create a request object with the path to the payment requests
var request = new RestRequest("swish-cpcapi/api/v1/paymentrequests");
// Create up a client certificate collection and import the certificate to it
X509Certificate2Collection clientCertificates = new X509Certificate2Collection();
clientCertificates.Import(_certDataBytes, _certificatePassword, X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet);
// Add client certificate collection to the RestClient
client.ClientCertificates = clientCertificates;
//X509Certificate2 certificates = new X509Certificate2(_certDataBytes, _certificatePassword);
//client.ClientCertificates = new X509CertificateCollection() { certificates };
// Add payment request data
request.AddJsonBody(requestData);
var response = client.Post(request);
var content = response.Content;
I have done what ever i can find on internet and i have used the service test environment with there own generated certificate and generated my own in there production environment with the same result..
I have tested set TLS 1.1 or TLS 1.2 to test, they specified TLS 1.1 on there own curl examples.
Anyone got any idea?
Update 2020-01-08 - I have got information from the service tech support that they only see me sending one certificate but when i trying to debug and checking the X509Certificate2Collection i finding 3 certificate. But they saying they only see one?

IMHO, if the service you are trying to access is protected via SSL cert with expecting public key/private key, then without the cert, you cant access it. If thats the intent of the service to be protected, i think you may only do to check the service health check or at max, check if the service is accessible (without having the client cert)
But just as HTTPS, then you can try to download the cert from the browser if you can access the service URL from your browser, say, to access their meta or a simple GET or something. In chrome, you may see a lock symbol (security icon) just before to the URL. click that, and you may possibly download the public cert. You can install that on your machine and try that.
In case, if that service has a pub cert and the access doesnt need the client cert, then above option may work. and i hope you are installing the CERT and access that via your code from the account that has access to the cert. Lets say, you install the cert under the LocalSystem, then you may need administrator access from code/solution to access that cert path. Or install the cert under the current_user path.
I would Check if am able to access the service from browser as the first step.
This is, just from what i have understood from your question. again, if you can explain whether the service is a protected service based on public key/private key, you need to have the access/cert to use that service.
UPDATE:
I have tried few options on my end, by creating a demo api and a demo client to use client certs. With what i have understood from your query, i assume below may be some of your options to try out.
// --- using the cert path if you have the path (instead of the byte[])
var myCert = new X509Certificate2("<path to the client cert.cer/.pfx>", "secure-password", X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet);
X509CertificateCollection clientCerts = new X509CertificateCollection();
clientCerts.Add(myCert);
OR
var certStore = new X509Store(StoreName.Root, StoreLocation.LocalMachine); //replace with appropriate values based on your cert configuration
certStore.Open(OpenFlags.ReadOnly);
//option 1 (ideally a client must have the cert thumbprint instead of a password
var cert = certStore.Certificates.Find(X509FindType.FindByThumbprint, "<cert Thumbprint>", false);
//option 2 (explore other options based on X509NameTypes
var cert = certStore.Certificates.OfType<X509Certificate2>()
.FirstOrDefault(cert => cert.GetNameInfo(X509NameType.DnsName, false) == "mycompany.dns.name.given in the cert");
client.ClientCertificates = new X509CertificateCollection(cert);

I recommend generate your own certificate
public static void MakeCert()
{
var ecdsa = ECDsa.Create(); // generate asymmetric key pair
var req = new CertificateRequest("cn=foobar", ecdsa, HashAlgorithmName.SHA256);
var cert = req.CreateSelfSigned(DateTimeOffset.Now, DateTimeOffset.Now.AddYears(10));
// Create PFX (PKCS #12) with private key
File.WriteAllBytes("c:\\temp\\mycert.pfx", cert.Export(X509ContentType.Pfx, "P#55w0rd"));
// Create Base 64 encoded CER (public key only)
File.WriteAllText("c:\\temp\\mycert.cer",
"-----BEGIN CERTIFICATE-----\r\n"
+ Convert.ToBase64String(cert.Export(X509ContentType.Cert), Base64FormattingOptions.InsertLineBreaks)
+ "\r\n-----END CERTIFICATE-----");
}
and then add to request
var client = new RestClient(url);
client.ClientCertificates = new X509CertificateCollection();
client.ClientCertificates.Add(new X509Certificate2("c:\\temp\\mycert.cer"));

How to determine if server has ssl certificate

I am creating a self-hosted owin server inside a windows service. I have implemented an ACME client to get a certificate from Let's Encrypt (to a domain given by the service's config.). However, if the service is run on a server which already has a certificate I do not need to request a new one. How can I determine, in code, if there is a certificate installed which applies for the domain set in the service's config?
The closest thing to a solution I found was to ignore existing certificates (if any) and always request a new one. Then when a certificate is received from Let's Encrypt, I save that certificate's serial to a file. On startup I then use the saved file (if any) to look for the existing certificate from the store:
public async Task<bool> NeedNewCertificate()
{
string certSerial = await AsyncFileHandler.ReadFileAsync(CERT_SERIAL_FILENAME);
using (var store = new X509Store(StoreName.My, StoreLocation.LocalMachine))
{
store.Open(OpenFlags.ReadOnly);
var certCollection = store.Certificates.Find(X509FindType.FindBySerialNumber, certSerial, true);
foreach (var cert in certCollection)
{
if (cert.NotBefore <= DateTime.Now && cert.NotAfter > DateTime.Now.AddDays(30)) // Let's Encrypt certificates are valid 90 days. They recommend renewing certificates every 30 days.
return false;
}
}
return true;
}

That's a good enough way of doing it I think.
Alternatively you can do a search in the certificate store that matches the parameters that you specify: the domain that the certificate is applied to, expiry date, etc. If you find the one that is valid, then you can use it.
That is in fact most likely the definition for what you mean by "certificate is installed on the server".
The attribute you probably would like to check is "Subject", e.g. you wold like these that have "CN = mydomain.com". You can have wildcard certificates as well, so you will need to figure out what types of certificates can be installed.

Checking certificate validity using HttpClientCertificate vs. X509Certificate2

My IIS (web server) requires client certificate and I need to check for certificate validity and read some information from and record in database (Audit)
I have following code
using System.Security.Cryptography.X509Certificates;
...
HttpClientCertificate cert = Request.ClientCertificate;
if (cert.IsPresent && cert.IsValid) {
X509Certificate2 cer = new X509Certificate2(cert.Certificate);
bool verified = cer.Verify();
...
AuditLog( ... );
}
cert.IsValid shows that certificate is valid. Do I need to instantiate X509Certificate2 object and re-check the validity of certificate (Why)?

If the certificate wasn't valid you wouldn't get this far. IIS should check that during the handshake, and abort the connection if invalid. All you need to do is verify that the identity represented by the Subject DN is authorized to be a client of this application.

Using SSL and SslStream for peer to peer authentication?

I need to provide secure communication between various processes that are using TCP/IP sockets for communication. I want both authentication and encryption. Rather than re-invent the wheel I would really like to use SSL and the SslStream class and self-signed certificates. What I want to do is validate the remote process's certificate against a known copy in my local application. (There doesn't need to be a certificate authority because I intend for the certificates to be copied around manually).
To do this, I want the application to be able to automatically generate a new certifiate the first time it is run. In addition to makecert.exe, it looks like this link shows a way to automatically generate self-signed certificates, so that's a start.
I've looked at the AuthenticateAsServer and AuthenticateAsClient methods of SslStream. You can provide call-backs for verification, so it looks like it's possible. But now that I'm into the details of it, I really don't think it's possible to do this.
Am I going in the right direction? Is there a better alternative? Has anyone done anything like this before (basically peer-to-peer SSL rather than client-server)?

Step 1: Generating a self-signed certificate:
I downloaded the Certificate.cs class posted by Doug Cook
I used this code to generate a .pfx certificate file:
byte[] c = Certificate.CreateSelfSignCertificatePfx(
"CN=yourhostname.com", //host name
DateTime.Parse("2000-01-01"), //not valid before
DateTime.Parse("2010-01-01"), //not valid after
"mypassword"); //password to encrypt key file
using (BinaryWriter binWriter = new BinaryWriter(
File.Open(#"testcert.pfx", FileMode.Create)))
{
binWriter.Write(c);
}
Step 2: Loading the certificate
X509Certificate cert = new X509Certificate2(
#"testcert.pfx",
"mypassword");
Step 3: Putting it together
I based it on this very simple SslStream example
You will get a compile time error about the SslProtocolType enumeration. Just change that from SslProtocolType.Default to SslProtocols.Default
There were 3 warnings about deprecated functions. I replaced them all with the suggested replacements.
I replaced this line in the Server Program.cs file with the line from Step 2:
X509Certificate cert = getServerCert();
In the Client Program.cs file, make sure you set serverName = yourhostname.com (and that it matches the name in the certificate)
In the Client Program.cs, the CertificateValidationCallback function fails because sslPolicyErrors contains a RemoteCertificateChainErrors. If you dig a little deeper, this is because the issuing authority that signed the certificate is not a trusted root.
I don`t want to get into having the user import certificates into the root store, etc., so I made a special case for this, and I check that certificate.GetPublicKeyString() is equal to the public key that I have on file for that server. If it matches, I return True from that function. That seems to work.
Step 4: Client Authentication
Here's how my client authenticates (it's a little different than the server):
TcpClient client = new TcpClient();
client.Connect(hostName, port);
SslStream sslStream = new SslStream(client.GetStream(), false,
new RemoteCertificateValidationCallback(CertificateValidationCallback),
new LocalCertificateSelectionCallback(CertificateSelectionCallback));
bool authenticationPassed = true;
try
{
string serverName = System.Environment.MachineName;
X509Certificate cert = GetServerCert(SERVER_CERT_FILENAME, SERVER_CERT_PASSWORD);
X509CertificateCollection certs = new X509CertificateCollection();
certs.Add(cert);
sslStream.AuthenticateAsClient(
serverName,
certs,
SslProtocols.Default,
false); // check cert revokation
}
catch (AuthenticationException)
{
authenticationPassed = false;
}
if (authenticationPassed)
{
//do stuff
}
The CertificateValidationCallback is the same as in the server case, but note how AuthenticateAsClient takes a collection of certificates, not just one certificate. So, you have to add a LocalCertificateSelectionCallback, like this (in this case, I only have one client cert so I just return the first one in the collection):
static X509Certificate CertificateSelectionCallback(object sender,
string targetHost,
X509CertificateCollection localCertificates,
X509Certificate remoteCertificate,
string[] acceptableIssuers)
{
return localCertificates[0];
}

you can look too this example
Sample Asynchronous SslStream Client/Server Implementation
http://blogs.msdn.com/joncole/archive/2007/06/13/sample-asynchronous-sslstream-client-server-implementation.aspx
if certificate is not produced correctly you can get exception The server mode SSL must use a certificate with the associated private key.
basic certificate example
makecert -sr LocalMachine -ss My -n CN=Test -sky exchange -sk 123456
or
as external file
makecert -sr LocalMachine -ss My -n CN=Test -sky exchange -sk 123456 c:\Test.cer
Certificate Creation Tool (Makecert.exe)
http://msdn.microsoft.com/en-us/library/bfsktky3%28VS.80%29.aspx

What you're proposing sounds fine to me, except that it sounds like you're looking to wait until the callback is invoked in order to generate the certificate. I don't think that that will fly; AFAIK, you've got to provide a valid certificate when you invoke AuthenticateAsX.
However, these classes are overridable; so in theory, you could create a derived class which first checks to see if a certificate needs to be generated, generates it if need be, then invokes the parent AuthenticateAsX method.