private static String buildRegistrationUri(final Principal principal, final OneTimeTokenAccount keyAccount,
                                               final CasConfigurationProperties casProperties) {
        val gauth = casProperties.getAuthn().getMfa().getGauth().getCore();
        return "otpauth://totp/" + gauth.getLabel() + ':' + principal.getId() + "?secret="
            + keyAccount.getSecretKey() + "&issuer=" + gauth.getIssuer();
    }
Flow scope attribute name indicating the account QR code.
support/cas-server-support-otp-mfa-core/src/main/java/org/apereo/cas/otp/web/flow/OneTimeTokenAccountCreateRegistrationAction.java