SSH HSM Public Key Authentication

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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.

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    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.

    pkcs11 := chilkat.NewPkcs11()

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

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

    //  Normal user = 1
    userType := 1

    success = pkcs11.QuickSession(userType,pin)
    if success == false {
        fmt.Println(pkcs11.LastErrorText())
        pkcs11.DisposePkcs11()
        return
    }

    //  Describe the private key object to be located on the HSM.
    json := chilkat.NewJsonObject()
    json.UpdateString("class","private_key")
    json.UpdateString("label","MySshKey")

    priv_handle := pkcs11.FindObject(json)
    if priv_handle == 0 {
        fmt.Println(pkcs11.LastErrorText())
        pkcs11.DisposePkcs11()
        json.DisposeJsonObject()
        return
    }

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

    pub_handle := pkcs11.FindObject(json)
    if pub_handle == 0 {
        fmt.Println(pkcs11.LastErrorText())
        pkcs11.DisposePkcs11()
        json.DisposeJsonObject()
        return
    }

    //  Create an SSH key object that uses the HSM handles.  The key type may be "rsa" or "ec".
    key := chilkat.NewSshKey()
    keyType := "rsa"
    success = key.UsePkcs11(pkcs11,priv_handle,pub_handle,keyType)
    if success == false {
        fmt.Println(key.LastErrorText())
        pkcs11.DisposePkcs11()
        json.DisposeJsonObject()
        key.DisposeSshKey()
        return
    }

    ssh := chilkat.NewSsh()

    port := 22
    success = ssh.Connect("ssh.example.com",port)
    if success == false {
        fmt.Println(ssh.LastErrorText())
        pkcs11.DisposePkcs11()
        json.DisposeJsonObject()
        key.DisposeSshKey()
        ssh.DisposeSsh()
        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 {
        fmt.Println(ssh.LastErrorText())
        pkcs11.DisposePkcs11()
        json.DisposeJsonObject()
        key.DisposeSshKey()
        ssh.DisposeSsh()
        return
    }

    fmt.Println("Public-key authentication successful.")

    ssh.Disconnect()

    pkcs11.Logout()
    pkcs11.CloseSession()

    pkcs11.DisposePkcs11()
    json.DisposeJsonObject()
    key.DisposeSshKey()
    ssh.DisposeSsh()