in pkg/provider/provider.go [596:607]
func parsePrivateKey(block []byte) (interface{}, error) {
if key, err := x509.ParsePKCS1PrivateKey(block); err == nil {
return key, nil
}
if key, err := x509.ParsePKCS8PrivateKey(block); err == nil {
return key, nil
}
if key, err := x509.ParseECPrivateKey(block); err == nil {
return key, nil
}
return nil, fmt.Errorf("failed to parse key for type pkcs1, pkcs8 or ec")
}