diff --git a/README.md b/README.md
index 8f617f7..64b6eb5 100644
--- a/README.md
+++ b/README.md
@@ -37,6 +37,7 @@ and no external requests — the page is fully self-contained.
 | `app.css` / `app.js` | Human-readable, unminified source of the styles/script that are inlined into `index.html`. Edit these, then re-minify and re-inline into `index.html` when publishing a change. |
 | `data/charmap.json` | The full character → Gen 1 byte value → species lookup table, generated from the source spreadsheet. Source of truth for `app.js`'s inlined data. |
 | `data/charmap.min.json` | Minified copy of the same table. |
+| `csp-hash.py` | Prints the `sha256-...` CSP tokens for `index.html`'s inline `<style>`/`<script>` blocks, for a host that locks down `Content-Security-Policy` to hashes instead of `'unsafe-inline'`. Re-run after re-inlining. |
 | `CHANGELOG.md` | Release history. |
 | `LICENSE` | GPLv3. |
 
diff --git a/csp-hash.py b/csp-hash.py
new file mode 100755
index 0000000..b3076c6
--- /dev/null
+++ b/csp-hash.py
@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+"""Print CSP sha256-... tokens for index.html's inline <style>/<script> blocks.
+
+Re-run this after editing index.html's inlined CSS/JS (i.e. after the
+re-minify/re-inline step described in the README), then paste the printed
+values into the nginx server block's Content-Security-Policy header.
+"""
+import base64
+import hashlib
+import pathlib
+import re
+
+html = pathlib.Path(__file__).with_name("index.html").read_text(encoding="utf-8")
+
+
+def csp_token(text):
+    digest = hashlib.sha256(text.encode("utf-8")).digest()
+    return "'sha256-" + base64.b64encode(digest).decode("ascii") + "'"
+
+
+style_match = re.search(r"<style[^>]*>(.*?)</style>", html, re.S)
+script_match = re.search(r"<script>(.*?)</script>", html, re.S)
+
+if not style_match or not script_match:
+    raise SystemExit("Couldn't find both an inline <style> and <script> block in index.html")
+
+print("style-src :", csp_token(style_match.group(1)))
+print("script-src:", csp_token(script_match.group(1)))