w = new Int8Array(sent);
    for (let cptr = 0; cptr < sent.byteLength; ++cptr)
        view[cptr] = cptr;

    writer.write(sent);
    const received = await reader.read();

    assert_equals(received.value.byteLength, 8);
    const view2 = new Int8Array(received.value);
    for (let cptr = 0; cptr < sent.byteLength; ++cptr)
        assert_equals(view2[cptr], view[cptr]);
}, "SFrame with array buffer - authentication size 10");

promise_test(async (test) => {
    const key = await crypto.subtle.importKey("