website-theme/layouts/shortcodes/pgpverify.html

{{- $openPGP := resources.Get "js/openpgp.min.js" -}}
<script src="{{ $openPGP.Permalink }}"></script>
<textarea id="pgpsignedtext" class="pgpform" style="width: 100%; min-height: 10rem;"></textarea>
<button class="pgpverifybutton" onclick="verify()">Verify</button>
<br/>
Verification Result:
<pre id="pgpverifyresult" class="pgpform"></pre>
<script>
async function verify() {
    let resultarea = document.querySelector('#pgpverifyresult');
    resultarea.textContent = "";

    let textarea = document.querySelector("#pgpsignedtext");
    if (textarea.value.length == 0) {
        return;
    }

    let pubKeyURL = "{{ .Get 0 }}";
    let pubKey;

    try {
        const response = await fetch(pubKeyURL);
        const text = await response.text();
        pubKey = await openpgp.readKey({ armoredKey: text });
    } catch {
        resultarea.textContent = "Error: Unable to obtain key";
    }

    try {
        const message = await openpgp.readCleartextMessage({ cleartextMessage: textarea.value });
        const verifyResult = await openpgp.verify({message: message, verificationKeys: pubKey});
        const validResult = await verifyResult.signatures[0].verified;
        resultarea.textContent = (validResult)? "Valid": "Invalid";
    } catch {
        resultarea.textContent = "Invalid";
    }

}
</script>