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Diffstat (limited to 'challenge.html')
| -rw-r--r-- | challenge.html | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/challenge.html b/challenge.html new file mode 100644 index 0000000..ea18794 --- /dev/null +++ b/challenge.html @@ -0,0 +1,114 @@ +<!DOCTYPE html> +<html lang="en"> +<head> + <meta charset="utf-8" /> + <meta name="viewport" content="width=device-width, initial-scale=1" /> + <title>Proof-of-work challenge</title> + <link rel="stylesheet" href="/.powxy/static/style.css" /> + <script> + /* + @licstart The following is the entire license notice for the + JavaScript code in this page. + + Copyright (C) 2025 Runxi Yu + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + 1. Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + 2. Redistributions in binary form must reproduce the above copyright + notice, this list of conditions and the following disclaimer in the + documentation and/or other materials provided with the distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS "AS IS" AND ANY + EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR + PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR + CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, + EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, + PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR + PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF + LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING + NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + @licend The above is the entire license notice + for the JavaScript code in this page. + */ + </script> +</head> +<body> + <main> + <header> + <h1>Proof-of-work challenge</h1> + </header> + + <section> + <p>This site is protected by <a href="{{ .Global.SourceURL }}">Powxy</a>{{ if .Global.Version }} {{ .Global.Version }}{{ end }}.</p> + <p>You must complete this proof-of-work challenge before you can access this site.</p> + </section> + + <section> + <p>Select a nonce no longer than 32 bytes, such that when it is appended to the decoded form of the challenge identifier, and the entire result is hashed with SHA-256, the first {{ .Global.NeedBits }} bits of the SHA-256 hash are all zeros. Within one octet, higher bits are considered to come before lower bits.</p> + <p>In other words, find an nonce <math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mi>N</mi><annotation encoding="application/x-tex">N</annotation></semantics></math> with <math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mo stretchy="false" form="prefix">|</mo><mi>N</mi><mo stretchy="false" form="postfix">|</mo><mo>≤</mo><mn>32</mn><mspace width="0.167em"></mspace><mi mathvariant="normal">B</mi></mrow><annotation encoding="application/x-tex">\lvert N\rvert \le 32\,\mathrm{B}</annotation></semantics></math>, such that <math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mrow><mi mathvariant="normal">S</mi><mi mathvariant="normal">H</mi><mi mathvariant="normal">A</mi><mn mathvariant="normal">256</mn></mrow><mrow><mo stretchy="true" form="prefix">(</mo><mi>I</mi><mspace width="0.167em"></mspace><mo stretchy="false" form="postfix">∥</mo><mspace width="0.167em"></mspace><mi>N</mi><mo stretchy="true" form="postfix">)</mo></mrow><mo><</mo><msup><mn>2</mn><mn>{{ .Global.NeedBitsReverse }}</mn></msup></mrow><annotation encoding="application/x-tex">\mathrm{SHA256}(I \,\|\, N) < 2^{{{ .Global.NeedBitsReverse }}}</annotation></semantics></math> in big endian, where <math display="inline" xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mi>I</mi><annotation encoding="application/x-tex">I</annotation></semantics></math> is the identifier provided below.</p> + <label for="unsigned-identifier">Challenge identifier (read-only)</label> + <input id="unsigned-identifier" type="text" readonly disabled tabindex="-1" value="{{ .Identifier }}" /> + </section> + + <section> + <form method="POST"> + <p>Encode your selected nonce in base64 and submit it below.</p> + <p>Please note that if your submission is successful, you will be given a cookie that will allow you to access this site for a period of time without having to complete the challenge again. By pressing the submit button, you agree to be given cookies for this purpose.</p> + <label for="nonce">Nonce</label> + <input id="nonce" name="powxy" type="text" /> + <input type="submit" value="Submit" /> + </form> + </section> + + {{- if .Message }} + <section> + <p><strong>{{ .Message }}</strong></p> + </section> + {{- end }} + + <section> + <p id="solver_status">JavaScript seems to be disabled. You must solve the challenge externally.</p> + </section> + + <section> + <p><a href="/.powxy/static/solver.c">A C implementation of the challenge solver</a> is available.</p> + </section> + </main> + + <script> + document.addEventListener("DOMContentLoaded", async function() { + let challenge_b64 = "{{ .Identifier }}"; + let difficulty = {{ .Global.NeedBits }}; + let form = document.querySelector("form"); + let field = form.querySelector("input[name='powxy']"); + let status_el = document.getElementById("solver_status"); + + let identifier_bytes = Uint8Array.from( + atob(challenge_b64), + ch => ch.charCodeAt(0) + ); + + status_el.textContent = "Starting WebAssembly solver as a worker..."; + + let worker = new Worker("/.powxy/static/solver.js"); + + worker.onmessage = function(e) { + let { nonce, nonce_bytes } = e.data; + let nonce_str = String.fromCharCode(...nonce_bytes); + field.value = btoa(nonce_str); + status_el.textContent = "Challenge solved automatically in " + nonce + " iterations"; + }; + + worker.postMessage({ identifier_bytes, difficulty }); + }); + </script> +</body> +</html> |