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+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width">
+    <title>Password Entropy calculator</title>
+    <style>
+        html {
+            font-family: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
+        }
+        body {
+            margin: 3em 1em;
+        }
+        form {
+            display: grid;
+            grid-template-columns: repeat(3, 1fr);
+            gap: 2rem 1rem;
+        }
+        input[type=range] {
+            display: block;
+        }
+
+        label[id] > output {
+            font-size: 2rem;
+            display: block;
+            border: 1px solid lightseagreen;
+            background-color: lightgreen;
+            padding: 0.5rem;
+            overflow: auto;
+            white-space: nowrap;
+            max-width: 100%;
+            box-sizing: border-box;
+        }
+
+        fieldset > label {
+            display: flex;
+            gap: 0.25em;
+            align-items: flex-start;
+        }
+
+        fieldset input {
+            display: inline-block;
+            transform: translateY(0.15em);
+        }
+
+        footer {
+            color: gray;
+            font-size: small;
+            margin-top: 3em;
+            text-align: center;
+        }
+
+        .standard > label:has(#common-words),
+        .standard > label:has(#common-words-pool),
+        .standard > label:has(#dictionary-pool),
+        .xkcd-symbols > label:has(#lowercase-latin-letters),
+        .xkcd-symbols > label:has(#uppercase-latin-letters),
+        .xkcd-symbols > label:has(#digits),
+        .xkcd-symbols > label:has(#special-chars),
+        .xkcd-symbols > label:has(#special-chars-pool),
+        .xkcd-symbols > label:has(#dictionary-pool),
+        .xkcd-dictionary > label:has(#common-words),
+        .xkcd-dictionary > label:has(#special-chars-pool),
+        .xkcd-dictionary > label:has(#common-words-pool) {
+            display: none;
+        }
+
+        fieldset {
+            grid-column: 1 / 4;
+        }
+
+        small {
+            color: gray;
+        }
+
+        b {
+            cursor: help;
+        }
+    </style>
+</head>
+<body>
+    <h1>XKCD Password strength demo</h1>
+    <form class="standard">
+        <fieldset>
+            <legend>Formel</legend>
+            <label>
+                <input type="radio" checked value="standard" id="formula-standard" name="formula">
+                <span>Standard (<code>log2(urval^längd)</code>)</span>
+            </label>
+            <label>
+                <input type="radio" value="xkcd-dictionary" id="formula-xkcd-dictionary" name="formula">
+                <span>XKCD uppslagsord + extra versaler, gemener eller specialtecken (<code>log2(65000*urval*urval)</code>)</span>
+            </label>
+            <label>
+                <input type="radio" value="xkcd-symbols" id="formula-xkcd-symbols" name="formula">
+                <span>XKCD symboler av vanliga ord (<code>log2(urval*antal)</code>)</span>
+            </label>
+        </fieldset>
+        <label id="length">
+            Lösenordslängd
+            <output>
+                &nbsp;
+            </output>
+        </label>
+        <label id="entropy">
+            Lösenordsentropi
+            <output>
+                &nbsp;
+            </output>
+        </label>
+        <label id="brute-force-estimate">
+            Brute force max <b title="1000 försök per sekund">?</b>
+            <output>
+                &nbsp;
+            </output>
+        </label>
+        <label>
+            <input type="range" step="1" max="50" value="0" id="lowercase-latin-letters" name="lowercase-latin-letters">
+            Latinska gemener <small>(a-z)</small>: <output></output>
+        </label>
+        <label>
+            <input type="range" step="1" max="50" value="0" id="uppercase-latin-letters" name="uppercase-latin-letters">
+            Latinska versaler <small>(A-Z)</small>: <output></output>
+        </label>
+        <label>
+            <input type="range" step="1" max="50" value="0" id="digits" name="digits">
+            Siffror <small>(0-9)</small>: <output></output>
+        </label>
+        <label>
+            <input type="range" step="1" max="50" value="0" id="special-chars" name="special-chars">
+            "Specialtecken" <small>(inkl Å, Ä och Ö)</small>: <output></output>
+        </label>
+        <label>
+            <input type="range" step="1" max="50" value="30" id="special-chars-pool" name="special-chars-pool">
+            Specialteckensurval: <output>30</output>
+        </label>
+        <label>
+            <input type="range" step="1" max="10" value="0" id="common-words" name="common-words">
+            Vanliga ord: <output></output>
+        </label>
+        <label>
+            <input type="range" step="128" max="4096" value="2048" id="common-words-pool" name="common-words-pool">
+            Vanliga ord-urval: <output>2048</output>
+        </label>
+        <label>
+            <input type="range" step="1000" max="100000" value="65000" id="dictionary-pool" name="dictionary-pool">
+            Uppslagsordsurval: <output>65000</output>
+        </label>
+    </form>
+    <footer>
+        <p>
+            Baserad på <a href="https://www.omnicalculator.com/other/password-entropy#password-entropy-is-not-all-that-matters">Omni Password Entropy Calculator</a>
+            men modifierad för att verifiera <a href="https://www.explainxkcd.com/wiki/index.php/936:_Password_Strength">XKCD 936</a>.
+            <br>Skapad okt 2025 av <a href="https://madr.se">madr</a>
+        </p>
+    </footer>
+    <script>
+        (function(G){
+            const $v = (id) => parseInt(document.getElementById(id).value, 10);
+            const inputs = document.querySelectorAll("input");
+            const lengthOutput = document.querySelector("#length > output");
+            const entropyOutput = document.querySelector("#entropy > output");
+            const bruteforceEstimateOutput = document.querySelector("#brute-force-estimate > output");
+            let mode = "standard";
+
+            calcBFE = (entropy) => {
+                let bfe = (2**entropy) / 1000
+                if (bfe < 1.0) {
+                    return "<1s"
+                }
+                if (bfe < 60.0) {
+                    return `~ ${Math.round(bfe)} sek`
+                }
+                bfe = bfe / 60
+                if (bfe < 60.0) {
+                    return `~ ${Math.round(bfe)} min`
+                }
+                bfe = bfe / 60
+                if (bfe < 24.0) {
+                    return `~ ${Math.round(bfe)} tim`
+                }
+                bfe = bfe / 24
+                if (bfe < 7.0) {
+                    return `~ ${Math.round(bfe)} dgr`
+                }
+                bfe = bfe / 7
+                if (bfe < 52.0) {
+                    return `~ ${Math.round(bfe)} v`
+                }
+                bfe = bfe * 7 / 30
+                if (bfe < 12.0) {
+                    return `~ ${Math.round(bfe)} mån`
+                }
+                bfe = bfe * 30 / 365
+                if (bfe < 100.0) {
+                    return `~ ${Math.round(bfe)} år`
+                }
+                return "> 100 år"
+            }
+
+            const calcEntropy = ({target: elm}) => {
+                if (elm.type == "range") {
+                    elm.parentNode.querySelector("output").innerHTML = elm.value;
+                } else {
+                    elm.form.className = elm.value;
+                    mode = elm.value;
+                }
+                let a, b, entropy;
+                const c = 27 * !!$v("lowercase-latin-letters") + 27 * !!$v("uppercase-latin-letters") + 10 * !!$v("digits") + 30 * !!$v("special-chars");
+                if (mode != "xkcd-symbols" && !c) {
+                    lengthOutput.innerHTML = "&nbsp;";
+                    entropyOutput.innerHTML = "&nbsp;";
+                    bruteforceEstimateOutput.innerHTML = "&nbsp;";
+                    return;
+                }
+                 if (mode == "standard") {
+                    a = c;
+                    b = $v("special-chars") + $v("digits") + $v("uppercase-latin-letters") + $v("lowercase-latin-letters");
+                    entropy = Math.floor(Math.log2(a**b));
+                } else if (mode == "xkcd-dictionary") {
+                    a = $v("dictionary-pool");
+                    b = c;
+                    entropy = Math.floor(Math.log2(a*b*b));
+                } else if (mode == "xkcd-symbols") {
+                    a = $v("common-words-pool");
+                    b = $v("common-words");
+                    entropy = Math.floor(Math.log2(a**b));
+                }
+                const passwordLength = (mode != "standard") ? "*" : $v("special-chars") + $v("digits") + $v("uppercase-latin-letters") + $v("lowercase-latin-letters");
+                lengthOutput.innerHTML = "";
+                lengthOutput.insertAdjacentHTML("afterbegin", passwordLength);
+                entropyOutput.innerHTML = "";
+                entropyOutput.insertAdjacentHTML("afterbegin", entropy);
+                bruteforceEstimateOutput.innerHTML = "";
+                bruteforceEstimateOutput.insertAdjacentHTML("afterbegin", calcBFE(entropy));
+            };
+            
+            inputs.forEach(function(elm) {
+                elm.onchange = (e) => calcEntropy(e)
+            })
+        }(this))
+    </script>
+</body>
+</html>
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