Ugly alternative to [nopaste](https://github.com/bokub/nopaste), but is a self-contained single-file HTML. [Live version](https://nopaste.ylxdzsw.com/)

nopaste_lite.html

<meta name="viewport" content="width=device-width, initial-scale=1"/>
<p><a href="https://caniuse.com/?search=deflate-raw">only these browsers are supported<a>
<p><textarea rows=10 cols=50 style="font: .9em monospace"></textarea>
<p><label>Password: <input></input></label> <button id="decrypt">Decrypt</button>
<p id="fool" style="display: none"><a href="https://xkcd.com/936/">Don't fool yourself with a weak password</a>
<p><button id="getlink">GetLink</button> (Will encrypt if password is not empty)
<pre><a></a></pre>
<script>
document.querySelector("#getlink").addEventListener("click", async () => {
    const text = document.querySelector("textarea").value
    const encoded = new TextEncoder().encode(text)
    const compressor = new CompressionStream("deflate-raw")
    const writer = compressor.writable.getWriter()
    writer.write(encoded).then(() => writer.close())
    let to_encode = await new Response(compressor.readable).arrayBuffer()
    const password = document.querySelector("input").value
    if (password) {
        if (password.length < 8)
            document.querySelector("#fool").style.display = "block"
        const iv = crypto.getRandomValues(new Uint8Array(12))
        const encrypted = await crypto.subtle.encrypt({ name: "AES-GCM", iv }, await get_key(password), to_encode)
        to_encode = [...iv, ...new Uint8Array(encrypted)]
    }
    const link = new URL('', location.href).href + '#' + btoa(String.fromCharCode(...new Uint8Array(to_encode)))
        .replace(/\+/g, "-")
        .replace(/\//g, "_")
        .replace(/=/g, "")
    document.querySelector("pre>a").href = link
    document.querySelector("pre>a").textContent = link
})
async function get_key(password) {
    const password_encoded = new TextEncoder().encode(password)
    const base_key = await crypto.subtle.importKey("raw", password_encoded, "PBKDF2", false, ["deriveKey"])
    return await crypto.subtle.deriveKey({
        name: "PBKDF2",
        salt: new Uint8Array([109, 111, 51, 57]),
        iterations: 201025,
        hash: "SHA-256"
    }, base_key, { name: "AES-GCM", length: 256 }, false, ["encrypt", "decrypt"])
}
async function decode() {
    try {
        const compressed = new Uint8Array(atob(location.hash.slice(1)
            .replace(/-/g, "+")
            .replace(/_/g, "/"))
            .split("")
            .map(c => c.charCodeAt(0)))
        const password = document.querySelector("input").value
        const to_decode = password
            ? await crypto.subtle.decrypt({ name: "AES-GCM", iv: compressed.slice(0, 12) }, await get_key(password), compressed.slice(12))
            : compressed
        const decompressor = new DecompressionStream("deflate-raw")
        const writer = decompressor.writable.getWriter()
        writer.write(to_decode).then(() => writer.close())
        const text = await new Response(decompressor.readable).text()
        document.querySelector("textarea").value = text
    } catch (e) {
        document.querySelector("textarea").value = "Decoding failed (It may be encrypted)."
    }
}
document.querySelector("input").addEventListener("input", () => document.querySelector("#fool").style.display = "none")
document.querySelector("#decrypt").addEventListener("click", decode)
if (location.hash.length > 1)
    decode()
</script>