Generate a CSR with SAN (Subject Alternative Name) Extension

Demonstrates how to generate a private key and a Certificate Signing Request (CSR) that includes the SAN extension.
Chilkat C# Downloads

bool success = false;

//  This requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

//  First generate an RSA private key.
//  (It is also possible to create CSRs based on ECDSA private keys..)
Chilkat.Rsa rsa = new Chilkat.Rsa();

//  Generate a random 2048-bit RSA key.
Chilkat.PrivateKey privKey = new Chilkat.PrivateKey();
success = rsa.GenKey(2048,privKey);
if (success == false) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

//  Create the CSR object and set properties.
Chilkat.Csr csr = new Chilkat.Csr();

//  Specify the Common Name. 
csr.CommonName = "mysubdomain.mydomain.com";

//  Country Name (2 letter code)
csr.Country = "GB";

//  State or Province Name (full name)
csr.State = "Yorks";

//  Locality Name (eg, city)
csr.Locality = "York";

//  Organization Name (eg, company)
csr.Company = "Internet Widgits Pty Ltd";

//  Organizational Unit Name (eg, secion/division)
csr.CompanyDivision = "IT";

//  Email address
csr.EmailAddress = "support@mydomain.com";

//  Add Subject Alternative Names
//  (The AddSan method is added in Chilkat v9.5.0.84)
//  Call AddSan for each alternative name.
success = csr.AddSan("dnsName","mydomain.com");
success = csr.AddSan("dnsName","mysubdomain.mydomain.com");
success = csr.AddSan("ipAddress","192.168.0.123");

//  Create the CSR using the private key.
string pemStr = csr.GenCsrPem(privKey);
if (csr.LastMethodSuccess != true) {
    Debug.WriteLine(csr.LastErrorText);
    return;
}

//  Save the private key and CSR to a files.
privKey.SavePkcs8EncryptedPemFile("password","qa_output/privKey1.pem");

Chilkat.FileAccess fac = new Chilkat.FileAccess();
fac.WriteEntireTextFile("qa_output/csr1.pem",pemStr,"utf-8",false);

//  Show the CSR.
Debug.WriteLine(pemStr);

//  Sample output:

//  	-----BEGIN CERTIFICATE REQUEST-----
//  	MIIC6jCCAdICAQAwgaQxITAfBgNVBAMMGG15c3ViZG9tYWluLm15ZG9tYWluLmNv
//  	bTELMAkGA1UEBhMCR0IxDjAMBgNVBAgMBVlvcmtzMQ0wCwYDVQQHDARZb3JrMSEw
//  	HwYDVQQKDBhJbnRlcm5ldCBXaWRnaXRzIFB0eSBMdGQxCzAJBgNVBAsMAklUMSMw
//  	IQYJKoZIhvcNAQkBFhRzdXBwb3J0QG15ZG9tYWluLmNvbTCCASIwDQYJKoZIhvcN
//  	AQEBBQADggEPADCCAQoCggEBALnQ0un/wF8whk+gPuiAlf3qvx14jgAOV6Erm6EB
//  	H7WACPCpnKcm/8KP+7uoPiwRQaENhMeCgf45vcivl2p6aAn/spLXyEkXyw2d8wFb
//  	YYAGRkiz4Xf7ASJiKuwcOtORz+sSDzgtdfokHfXU1cYeFE2yQhSdLUY5fMn425+g
//  	KoEEsRSjSDe6AKru4+4iGNrLKd8pB9IA5/jOE139IkWlB9r5fEPD5bUTsgqXk9eb
//  	68O0gc712V2eZK07N24lDmFC4bIMTD4csDWocR5hFHXj7NX7c8sOBDcpEb9mPIk4
//  	elxubnhkfnjhOi4J3lDHcT/0ALnbLhf9LnaiKqs+5VcVZvECAwEAAaAAMA0GCSqG
//  	SIb3DQEBBQUAA4IBAQC0AETLIcP3foh5nbu2hVFS8uCUNZ5hEIR1eXmYZmZoBQq2
//  	26ZAoT4CZwixlggC+n7WvAXJ5Pzxpl4wLV4loTiQzaKPX1w0ERo5ZRwLy0n56oG2
//  	6QG+WTViT1C8rlgtVwkCFNOXr0kSSRs8FdaPllqKxK1hxYSL7zwNpumsk39F2cDt
//  	vhcekvH0V3BuGrQFm3dKN/0azW6GOod9+Vq4VzSyOe3kp15oxLBsZOFOu/REujcw
//  	Tzu2jt1asQKUm60CZ9wNHpYepR0Ww40uP1slbehEaFDa6V8b60/tlHHmBbJ4/fy5
//  	hJnYCvjzFz4O9VtT+JtP9ldRHWV3KpZ8ne3AjD+F
//  	-----END CERTIFICATE REQUEST-----