[Solved] Is there a type of password protection that works on local files? [closed]

by


Well, how about

function gamma(text, key) {
    let res="",
        i = 0;

    for (let c of text)
        res += String.fromCharCode(
            c.charCodeAt(0) ^ key.charCodeAt(i++ % key.length))

    return res
}

site = "Z\t\u001d\u0005\u0012O\u0011\u0004\n\u0000\u0000VA\f\u000b\n\bHL\u0003\u000fO\u0006\u0003\u0003\u001d\u0017WI\t\u001d\u0005\u0012Q"

onload = function() {
    document.body.innerHTML = gamma(site, prompt('password?'))
}

Unless you enter a valid password (which happens to be “fork”), you’ll get rubbish instead of the site.

Basically, it “encrypts” the whole web page (using a naive gamming algorithm). Since this a symmetric encryption, the same key can be used to turn the text back into the initial state.

Here’s a small snippet to automate the whole thing:

function gamma(text, key) {
  let res="", i = 0;
  for (let c of text)
    res += String.fromCharCode(c.charCodeAt(0) ^ key.charCodeAt(i++ % key.length))
  return res
}

$ = x => document.getElementById(x)

encode = function() {
  let site = $('site').value,
    pass = $('pass').value
  let enc = JSON.stringify(gamma(site, pass))

  $('out').value = [
    '<script>',
    `site = ${enc}`,
    gamma,
    'onload = function() {',
    'document.body.innerHTML = gamma(site, prompt("password?"))',
    '}</' + 'script>'
  ].join('\n')
}
<h3>Ultimate web protector, patent pending!</h3>

<p><textarea id="site" cols=80 rows=10>my site</textarea></p>
<p><input id="pass" value="my password"></p>
<p><button onclick="encode()">Encode!</button></p>
<p><textarea id="out" cols=80 rows=10></textarea></p>

For future readers: this code is a joke, don’t even think about using it to actually protect anything serious! However, if you replace the naive “encryption” above with a proven algorithm like AES, this can be used as a prototype for a real-world solution if you have a serverless environment, but still need to password-protect things.

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solved Is there a type of password protection that works on local files? [closed]