问题
I have a self-hosted WCF server running as a Windows service under the Local System account. I am trying to create a self-signed certificate programmatically in c# for use with a net.tcp endpoint using Message level security.
I am using the following code which is very closely based on the accepted answer in How to create a self-signed certificate using C#? with some small changes trying to solve my problem.
public static X509Certificate2 CreateSelfSignedCertificate(string subjectName, TimeSpan expirationLength)
{
// create DN for subject and issuer
var dn = new CX500DistinguishedName();
dn.Encode("CN=" + subjectName, X500NameFlags.XCN_CERT_NAME_STR_NONE);
CX509PrivateKey privateKey = new CX509PrivateKey();
privateKey.ProviderName = "Microsoft Strong Cryptographic Provider";
privateKey.Length = 1024;
privateKey.KeySpec = X509KeySpec.XCN_AT_KEYEXCHANGE;
privateKey.KeyUsage = X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_DECRYPT_FLAG | X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_KEY_AGREEMENT_FLAG;
privateKey.MachineContext = true;
privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_EXPORT_FLAG;
privateKey.Create();
// Use the stronger SHA512 hashing algorithm
var hashobj = new CObjectId();
hashobj.InitializeFromAlgorithmName(ObjectIdGroupId.XCN_CRYPT_HASH_ALG_OID_GROUP_ID,
ObjectIdPublicKeyFlags.XCN_CRYPT_OID_INFO_PUBKEY_ANY,
AlgorithmFlags.AlgorithmFlagsNone, "SHA1");
// Create the self signing request
var cert = new CX509CertificateRequestCertificate();
cert.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextMachine, privateKey, "");
cert.Subject = dn;
cert.Issuer = dn; // the issuer and the subject are the same
cert.NotBefore = DateTime.Now.Date;
// this cert expires immediately. Change to whatever makes sense for you
cert.NotAfter = cert.NotBefore + expirationLength;
//cert.X509Extensions.Add((CX509Extension)eku); // add the EKU
cert.HashAlgorithm = hashobj; // Specify the hashing algorithm
cert.Encode(); // encode the certificate
// Do the final enrollment process
var enroll = new CX509Enrollment();
enroll.InitializeFromRequest(cert); // load the certificate
enroll.CertificateFriendlyName = subjectName; // Optional: add a friendly name
string csr = enroll.CreateRequest(); // Output the request in base64
// and install it back as the response
enroll.InstallResponse(InstallResponseRestrictionFlags.AllowUntrustedCertificate,
csr, EncodingType.XCN_CRYPT_STRING_BASE64, ""); // no password
// output a base64 encoded PKCS#12 so we can import it back to the .Net security classes
var base64encoded = enroll.CreatePFX("", // no password, this is for internal consumption
PFXExportOptions.PFXExportChainWithRoot);
// instantiate the target class with the PKCS#12 data (and the empty password)
return new System.Security.Cryptography.X509Certificates.X509Certificate2(
System.Convert.FromBase64String(base64encoded), "",
// mark the private key as exportable (this is usually what you want to do)
// mark private key to go into the Machine store instead of the current users store
X509KeyStorageFlags.Exportable | X509KeyStorageFlags.MachineKeySet
);
}
And I store it with this code:
X509Store store = new X509Store(storeName, StoreLocation.LocalMachine);
store.Open(OpenFlags.ReadWrite);
store.Add(newCert);
store.Close();
This creates the certificate and puts it in the LocalMachine certificate store. The problem is that when I try to start the WCF service I get the following exception:
It is likely that certificate 'CN=myCertificate' may not have a private key that is capable of key exchange or the process may not have access rights for the private key. Please see inner exception for detail. Inner exception: Keyset does not exist
The output of the FindPrivateKey sample (http://msdn.microsoft.com/en-us/library/aa717039%28v=vs.100%29.aspx) for my certificate is:
Private key directory:
C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys
Private key file name:
f0d47c7826b8ef5148b6d412f1c40024_4a8a026f-58e4-40f7-b779-3ae9b6aae1a7
I can see this 1.43KB file in explorer. If I look at the properties|Security I see SYSTEM and Administrators both with Full control.
In researching this error I have seen many answers about the private key missing or incorrect permissions. I can't see what the problem is.
The really strange thing is that if I use the mmc Certificate plugin, go to the certificate and choose All Tasks|Manage Private Keys... I see the same security settings. After viewing this even if I just bring up the dialog and hit the Cancel button the certificate now works correctly in WCF. I can simply restart the service and everything runs perfectly.
If I create a certificate using MakeCert it works just fine from the start. I don't know what it does differently.
One other piece of information that may not be relevant is that the certificate not only gets put in the My store where I told it to get put, but it also gets put in the "Intermediate Certification Authorities" store. I don't know why or if it matters.
So...any ideas what I am doing wrong?
UPDATE: Well, this is not just a WCF issue. I essentially get the same problem when I try to use the certificate to bind to an endpoint with http.sys using HttpSetServiceConfiguration. The method returns 1312 - "A specified logon session does not exist. It may already have been terminated". This is actually not the real error. I saw in the Security Event log an Audit Failure that say this:
Cryptographic Parameters:
Provider Name: Microsoft Software Key Storage Provider
Algorithm Name: Not Available.
Key Name: {A23712D0-9A7B-4377-89DB-B1B39E3DA8B5}
Key Type: Machine key.
Cryptographic Operation:
Operation: Open Key.
Return Code: 0x80090011
0x80090011 is Object was not found. So this appears to be the same problem. Again, after I open the Manage Private Keys dialog for the certificate this works perfectly also.
I am still looking for the cause of the problem.
UPDATE #2: I was able to get this working using the accepted answer below. Interestingly, this code now seems to put the certificate in the Machine store without calling the X509Store code. I still call the code because I am not sure and it does not hurt anything. Here is the final code that I am using to create the certificate.
static public X509Certificate2 CreateSelfSignedCertificate(string subjectName, TimeSpan expirationLength)
{
// create DN for subject and issuer
var dn = new CX500DistinguishedName();
dn.Encode("CN=" + subjectName, X500NameFlags.XCN_CERT_NAME_STR_NONE);
CX509PrivateKey privateKey = new CX509PrivateKey();
privateKey.ProviderName = "Microsoft Strong Cryptographic Provider";
privateKey.Length = 2048;
privateKey.KeySpec = X509KeySpec.XCN_AT_KEYEXCHANGE;
privateKey.KeyUsage = X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_DECRYPT_FLAG | X509PrivateKeyUsageFlags.XCN_NCRYPT_ALLOW_KEY_AGREEMENT_FLAG;
privateKey.MachineContext = true;
privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_PLAINTEXT_EXPORT_FLAG;
privateKey.Create();
// Use the stronger SHA512 hashing algorithm
var hashobj = new CObjectId();
hashobj.InitializeFromAlgorithmName(ObjectIdGroupId.XCN_CRYPT_HASH_ALG_OID_GROUP_ID,
ObjectIdPublicKeyFlags.XCN_CRYPT_OID_INFO_PUBKEY_ANY,
AlgorithmFlags.AlgorithmFlagsNone, "SHA512");
// Create the self signing request
var cert = new CX509CertificateRequestCertificate();
cert.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextMachine, privateKey, "");
cert.Subject = dn;
cert.Issuer = dn; // the issuer and the subject are the same
cert.NotBefore = DateTime.Now.Date;
// this cert expires immediately. Change to whatever makes sense for you
cert.NotAfter = cert.NotBefore + expirationLength;
cert.HashAlgorithm = hashobj; // Specify the hashing algorithm
cert.Encode(); // encode the certificate
// Do the final enrollment process
var enroll = new CX509Enrollment();
enroll.InitializeFromRequest(cert); // load the certificate
enroll.CertificateFriendlyName = subjectName; // Optional: add a friendly name
string csr = enroll.CreateRequest(); // Output the request in base64
// and install it back as the response
enroll.InstallResponse(InstallResponseRestrictionFlags.AllowUntrustedCertificate,
csr, EncodingType.XCN_CRYPT_STRING_BASE64, ""); // no password
// output a base64 encoded PKCS#12 so we can import it back to the .Net security classes
var base64encoded = enroll.CreatePFX("", // no password, this is for internal consumption
PFXExportOptions.PFXExportChainWithRoot);
// instantiate the target class with the PKCS#12 data (and the empty password)
return new System.Security.Cryptography.X509Certificates.X509Certificate2(
System.Convert.FromBase64String(base64encoded), "",
// mark the private key as exportable (this is usually what you want to do)
// mark private key to go into the Machine store instead of the current users store
X509KeyStorageFlags.Exportable | X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.PersistKeySet
);
}
回答1:
I had the same issue using the equivalent code in PowerShell. It appears that sometime the private key just disappears. I used Process Monitor and you can see the key file being deleted.
The way I solved this was to add X509KeyStorageFlags.PersistKeySet to the X509Certificate2 constructor.
回答2:
I could not make this work, but I found an alternate solution. (Update December 2014: I have now gotten it to work using the accepted answer.)
I was able to use the PluralSight.Crypto library to achieve what I need. I had to modify the source code slightly to get the private key to store in the LocalMachine store. The changes I made were to the file CryptContext.cs. I changed the CreateSelfSignedCertificate method. Following is a snippet of code including the change that I made. In essence, I set the Flags member of the CryptKeyProviderInformation structure to set it to 0x20 (CRYPT_MACHINE_KEYSET) if the CryptContext object contains this value in its Flags.
byte[] asnName = properties.Name.RawData;
GCHandle asnNameHandle = GCHandle.Alloc(asnName, GCHandleType.Pinned);
int flags = 0; // New code
if ((this.Flags & 0x20) == 0x20) // New code
flags = 0x20; // New code
var kpi = new Win32Native.CryptKeyProviderInformation
{
ContainerName = this.ContainerName,
KeySpec = (int)KeyType.Exchange,
ProviderType = 1, // default RSA Full provider
Flags = flags // New code
};
Then I use the function in my own code like this:
using (Pluralsight.Crypto.CryptContext ctx = new Pluralsight.Crypto.CryptContext()) {
ctx.Flags = 0x8 | 0x20;
ctx.Open();
X509Certificate2 cert = ctx.CreateSelfSignedCertificate(
new Pluralsight.Crypto.SelfSignedCertProperties
{
IsPrivateKeyExportable = true,
KeyBitLength = 4096,
Name = new X500DistinguishedName("CN=" + subjectName),
ValidFrom = DateTime.Today,
ValidTo = DateTime.Today + expirationLength,
});
return cert;
}
Notice that I set the Flags for the CryptContext object to be 0x8 | 0x20 (CRYPT_NEWKEYSET | CRYPT_MACHINE_KEYSET).
I wish I could figure out what was wrong with my original solution. But I need something to work and in my testing this solution does what I need. I hope it helps someone else along the way.
回答3:
You can also use the CLR Security library on CodePlex (https://clrsecurity.codeplex.com/). Here is sample code which creates a self signed certificate, and tests it with SSLStream.
var machineName = Environment.MachineName;
var keyCreationParameters = new CngKeyCreationParameters();
keyCreationParameters.KeyUsage = CngKeyUsages.AllUsages;
keyCreationParameters.KeyCreationOptions = CngKeyCreationOptions.OverwriteExistingKey;
keyCreationParameters.Parameters.Add(new CngProperty("Length", BitConverter.GetBytes(4096), CngPropertyOptions.None));
var cngKey = CngKey.Create(CngAlgorithm2.Rsa, "Test", keyCreationParameters);
var x500DistinguishedName = new X500DistinguishedName("CN=" + machineName);
x500DistinguishedName.Oid.Value = "1.3.6.1.5.5.7.3.1";
var certificateCreationParameters = new X509CertificateCreationParameters(x500DistinguishedName);
certificateCreationParameters.SignatureAlgorithm = X509CertificateSignatureAlgorithm.RsaSha512;
certificateCreationParameters.TakeOwnershipOfKey = true;
certificateCreationParameters.CertificateCreationOptions = X509CertificateCreationOptions.None;
certificateCreationParameters.EndTime = new DateTime(9999, 12,31, 23, 59, 59, 999, DateTimeKind.Utc);
var certificate = cngKey.CreateSelfSignedCertificate(certificateCreationParameters);
var certificateStore = new X509Store(StoreName.Root, StoreLocation.CurrentUser);
certificateStore.Open(OpenFlags.ReadWrite);
certificateStore.Add(certificate);
certificateStore.Close();
var tcpListener = TcpListener.Create(6666);
tcpListener.Start();
var client = new TcpClient("localhost", 6666);
var acceptedClient = tcpListener.AcceptTcpClient();
var acceptedClinetSslStream = new SslStream(
acceptedClient.GetStream(), false);
var serverAuthTask = acceptedClinetSslStream.AuthenticateAsServerAsync(certificate,
false, SslProtocols.Tls, true);
SslStream clientSslStream = new SslStream(
client.GetStream(),
false,
delegate(object o, X509Certificate x509Certificate, X509Chain chain, SslPolicyErrors errors)
{
if (errors == SslPolicyErrors.None)
return true;
Console.WriteLine("Certificate error: {0}", errors);
// Do not allow this client to communicate with unauthenticated servers.
return false;
},
null);
var clientAuthTask = clientSslStream.AuthenticateAsClientAsync(machineName);
Task.WaitAll(serverAuthTask, clientAuthTask);
来源：https://stackoverflow.com/questions/18339706/how-to-create-self-signed-certificate-programmatically-for-wcf-service