SSH HSM Public Key Authentication

See more SSH Examples

Demonstrates SSH public-key authentication using a private key stored on an HSM — a USB token or smart card — accessed through PKCS#11. A session is opened with the vendor's driver, the key handles are located, and an SshKey object is bound to them with UsePkcs11.

Background: The point of an HSM is that the private key is generated on the device and cannot be exported: the signing operation happens on the hardware, so the key material never reaches your application's memory or disk. Even a fully compromised host cannot yield a copy of the key. PKCS#11 is the vendor-neutral interface to such devices, which is why the driver path and the object-finding template are the only vendor-specific parts of this example.

Chilkat C# Downloads

Download Chilkat for C#

bool success = false;

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

//  Demonstrates SSH public-key authentication using a private key stored on an HSM (a USB token
//  or smart card) accessed through PKCS#11.
//  
//  Note: Chilkat's PKCS#11 implementation runs on Windows, Linux, macOS, and other supported
//  operating systems.

Chilkat.Pkcs11 pkcs11 = new Chilkat.Pkcs11();

//  The PKCS#11 driver supplied by your HSM vendor: a .dll on Windows, a .so on Linux, or a
//  .dylib on macOS.
pkcs11.SharedLibPath = "C:/Program Files (x86)/Gemalto/IDGo 800 PKCS#11/IDPrimePKCS1164.dll";

//  The PIN should come from a secure source rather than being hard-coded.
string pin = "0000";

//  Normal user = 1
int userType = 1;

success = pkcs11.QuickSession(userType,pin);
if (success == false) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

//  Describe the private key object to be located on the HSM.
Chilkat.JsonObject json = new Chilkat.JsonObject();
json.UpdateString("class","private_key");
json.UpdateString("label","MySshKey");

uint priv_handle = pkcs11.FindObject(json);
if (priv_handle == 0) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

//  Find the corresponding public key by changing the class in the same template.
json.UpdateString("class","public_key");

uint pub_handle = pkcs11.FindObject(json);
if (pub_handle == 0) {
    Debug.WriteLine(pkcs11.LastErrorText);
    return;
}

//  Create an SSH key object that uses the HSM handles.  The key type may be "rsa" or "ec".
Chilkat.SshKey key = new Chilkat.SshKey();
string keyType = "rsa";
success = key.UsePkcs11(pkcs11,priv_handle,pub_handle,keyType);
if (success == false) {
    Debug.WriteLine(key.LastErrorText);
    return;
}

Chilkat.Ssh ssh = new Chilkat.Ssh();

int port = 22;
success = ssh.Connect("ssh.example.com",port);
if (success == false) {
    Debug.WriteLine(ssh.LastErrorText);
    return;
}

//  The corresponding public key must already be installed on the SSH server for the account.
//  The signing operation happens on the HSM -- the private key never leaves the device.
success = ssh.AuthenticatePk("mySshLogin",key);
if (success == false) {
    Debug.WriteLine(ssh.LastErrorText);
    return;
}

Debug.WriteLine("Public-key authentication successful.");

ssh.Disconnect();

pkcs11.Logout();
pkcs11.CloseSession();