@Override
    public List<Credential> fromRequest(final HttpServletRequest request, final MultiValueMap<String, String> requestBody) {
        if (requestBody == null || requestBody.isEmpty()) {
            LOGGER.debug("Skipping [{}] because the requestBody is null or empty", getClass().getSimpleName());
            return new ArrayList<>();
        }
        val token = requestBody.getFirst(PARAMETER_NAME_CAS_SIMPLE_OTP);
        if (StringUtils.isBlank(token)) {
            return new ArrayList<>();
        }
        val creds = new CasSimpleMultifactorTokenCredential(token);
        return CollectionUtils.wrap(prepareCredential(request, creds));
    }
Parameter name expected in the request body to contain the token
based on which credential will be created.
support/cas-server-support-simple-mfa-core/src/main/java/org/apereo/cas/mfa/simple/rest/CasSimpleMultifactorRestHttpRequestCredentialFactory.java