private String createAuthEncoded() {
        JsonObject ret = new JsonObject();
        if (identityToken != null) {
            putNonNull(ret, AUTH_IDENTITY_TOKEN, identityToken);
        } else {
            putNonNull(ret, AUTH_USERNAME, username);
            putNonNull(ret, AUTH_PASSWORD, password);
            putNonNull(ret, AUTH_EMAIL, email);
            putNonNull(ret, AUTH_AUTH, auth);
        }

        return encodeBase64(ret.toString());
    }
Constructor which takes a base64 encoded credentials in the form 'user:password'

@param credentialsEncoded the docker encoded user and password
@param email the email to use for authentication
src/main/java/io/fabric8/maven/docker/access/AuthConfig.java