btcpayserver/BTCPayServer/Views/UIManage/EnableAuthenticator.cshtml

@model EnableAuthenticatorViewModel
@{
    ViewData.SetActivePage(ManageNavPages.TwoFactorAuthentication, "Enable authenticator app");
}

<div class="col-xl-8 col-xxl-constrain">
    <h3>Enable Authenticator</h3>
    <p class="my-3">To use an authenticator app go through the following steps:</p>
    <ol class="list">
        <li class="mb-5">
            <div class="mb-2">Download a two-factor authenticator app like …</div>
            <ul>
                <li>
                    Microsoft Authenticator for
                    <a href="https://play.google.com/store/apps/details?id=com.azure.authenticator" rel="noreferrer noopener">Android</a> or
                    <a href="https://itunes.apple.com/us/app/microsoft-authenticator/id983156458" rel="noreferrer noopener">iOS</a>
                </li>
                <li>
                    Google Authenticator for
                    <a href="https://play.google.com/store/apps/details?id=com.google.android.apps.authenticator2&amp;hl=en" rel="noreferrer noopener">Android</a> or
                    <a href="https://itunes.apple.com/us/app/google-authenticator/id388497605?mt=8" rel="noreferrer noopener">iOS</a>
                </li>
            </ul>
        </li>
        <li class="mb-5">
            <p class="mb-2">Scan the QR Code or enter the following key into your two-factor authenticator app:</p>
            <p class="mb-4">
                <code class="me-3">@Model.SharedKey</code>
                <span class="text-secondary">(spaces and casing do not matter)</span>
            </p>
            <div id="qrCode"></div>
            <div id="qrCodeData" data-url="@Model.AuthenticatorUri"></div>
        </li>
        <li>
            <p>
                Your two-factor authenticator app will provide you with a unique code.
                <br/>
                Enter the code in the confirmation box below.
            </p>    
            <form method="post">
                <input asp-for="AuthenticatorUri" type="hidden" />
                <input asp-for="SharedKey" type="hidden" />
                <div class="form-group">
                    <label asp-for="Code" class="form-label">Verification Code</label>
                    <input asp-for="Code" class="form-control" autocomplete="off" autofocus style="width:14ch"/>
                    <span asp-validation-for="Code" class="text-danger"></span>
                </div>
                <button type="submit" class="btn btn-primary mt-2">Verify</button>
                <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            </form>
        </li>
    </ol>
</div>

@section PageFootContent {
    <partial name="_ValidationScriptsPartial" />
    <script src="~/js/qrcode.js" asp-append-version="true"></script>
    <script>
        new QRCode(document.getElementById("qrCode"), {
            text: @Safe.Json(Model.AuthenticatorUri),
            width: 200,
            height: 200,
            useSVG: true,
            correctLevel : QRCode.CorrectLevel.M
        });
        $("#qrCode > img").css({ "margin": "auto" });
    </script>
}