6 files changed, 532 insertions, 0 deletions
diff --git a/crates/chat-crypto/Cargo.toml b/crates/chat-crypto/Cargo.toml
new file mode 100644
index 0000000..eaada21
--- /dev/null
+++ b/crates/chat-crypto/Cargo.toml
@@ -0,0 +1,37 @@
+# Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+[package]
+name = "stack-chat-crypto"
+version = "0.1.0"
+edition = "2024"
+license = "AGPL-3.0-or-later"
+authors = ["Doan Luu Duc Tai <doan@luuduct.ai>"]
+description = "Experimental OpenPGP browser compatibility proof for private chat."
+repository = "https://git.doan.luuduct.ai/stack"
+readme = "README.txt"
+keywords = ["openpgp", "wasm", "chat"]
+categories = ["cryptography"]
+publish = false
+
+[lib]
+crate-type = ["rlib"]
+
+[dependencies]
+anyhow = "1"
+sequoia-openpgp = { version = "=2.4.2", default-features = false, features = ["crypto-openssl"] }
+
+[lints]
+workspace = true
diff --git a/crates/chat-crypto/README.txt b/crates/chat-crypto/README.txt
new file mode 100644
index 0000000..d09ff82
--- /dev/null
+++ b/crates/chat-crypto/README.txt
@@ -0,0 +1,57 @@
+Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU Affero General Public License as
+published by the Free Software Foundation, either version 3 of the
+License, or (at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU Affero General Public License for more details.
+
+You should have received a copy of the GNU Affero General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+
+CHAT CRYPTOGRAPHY COMPATIBILITY PROBE
+
+    Experimental, local-only work on feature/private-chat. This is a
+    cryptographic compatibility test, not a messaging application. Do not use
+    it for private conversations or real identities. It creates temporary
+    identities in memory and discards them; it does not create user chat files.
+
+    Fixed encryption: RFC 9980 ML-KEM-1024 + X448, OpenPGP v6.
+    Tested signing: ML-DSA-87 + Ed448, OpenPGP v6.
+    Backend: Sequoia 2.4.2 with OpenSSL 3.6.5. No algorithm substitution or
+    vulnerability-advisory exception was used. The first checkpoint's Rust
+    backend is historical and no longer selected.
+
+    See ../../docs/CHAT-OPENSSL-MIGRATION.txt for the complete decision record,
+    pinned source hashes, build flags, capability boundaries, dependency-policy
+    exceptions, observed results, limitations, and reproduction commands.
+    ../../docs/CHAT-SECURITY-REVIEW.txt records the original dependency findings.
+    ../../docs/CHAT-DESIGN.txt describes the planned application.
+
+QUICK CHECKS FROM THE STACK ROOT
+
+        cargo test --locked -p stack-chat-crypto
+        cargo run --locked -p stack-chat-crypto
+        sh infra/chat/build-openssl-wasi.sh
+        PLAYWRIGHT_BROWSERS_PATH="$PWD/.tools/browsers" node crates/chat-crypto/tests/browser.mjs
+        cargo stack check
+
+    Native checks require OpenSSL >=3.5 development files and libclang.
+    The cross-build script currently supports Linux x86_64 development hosts.
+    Browser tooling installation is documented in the migration record.
+
+    The harness serves only a blank document, a readable AGPL JavaScript WASI
+    bridge, and the new WASI binary on an ephemeral loopback port. It verifies
+    the actual OpenSSL backend, cryptographic round trips, tampering and invalid
+    credential rejection, repeated fresh instances, and failure without CSPRNG.
+    It checks for external requests and persistent browser application state.
+
+    The application itself, private chat-file envelope, and session workflow
+    remain unimplemented. LibreJS acceptance has not been tested; there is no
+    public chat page or compliance badge. The fixture password is public test
+    data, not a configured secret. No .env file or user private key is needed.
diff --git a/crates/chat-crypto/browser/wasi.mjs b/crates/chat-crypto/browser/wasi.mjs
new file mode 100644
index 0000000..d27fe4b
--- /dev/null
+++ b/crates/chat-crypto/browser/wasi.mjs
@@ -0,0 +1,106 @@
+// Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+// @license magnet:?xt=urn:btih:0b31508aeb0634b347b8270c7bee4d411b5d4109&dn=agpl-3.0.txt AGPL-3.0
+
+export async function runProbe(bytes) {
+    let memory;
+    let output = '';
+    let errors = '';
+    let randomCalls = 0;
+    let randomBytes = 0;
+    const data = () => new DataView(memory.buffer);
+    const put32 = (address, value) => data().setUint32(address, value, true);
+    const noEntries = (count, size) => { put32(count, 0); put32(size, 0); return 0; };
+    class Exit extends Error {
+        constructor(code) { super(`WASI exit ${code}`); this.code = code; }
+    }
+    const wasi = {
+        args_sizes_get: noEntries,
+        environ_sizes_get: noEntries,
+        args_get: () => 0,
+        environ_get: () => 0,
+        random_get(address, length) {
+            const buffer = new Uint8Array(memory.buffer, address, length);
+            for (let offset = 0; offset < length; offset += 65536) {
+                crypto.getRandomValues(buffer.subarray(offset, Math.min(offset + 65536, length)));
+            }
+            randomCalls += 1;
+            randomBytes += length;
+            return 0;
+        },
+        clock_time_get(clock, precision, address) {
+            if (clock !== 0 && clock !== 1) return 52;
+            const milliseconds = clock === 0 ? Date.now() : performance.now();
+            data().setBigUint64(address, BigInt(Math.floor(milliseconds * 1000000)), true);
+            return 0;
+        },
+        clock_res_get(clock, address) { data().setBigUint64(address, 1000000n, true); return 0; },
+        fd_write(fd, vectors, count, written) {
+            if (fd !== 1 && fd !== 2) return 8;
+            let total = 0;
+            for (let index = 0; index < count; index += 1) {
+                const address = data().getUint32(vectors + index * 8, true);
+                const length = data().getUint32(vectors + index * 8 + 4, true);
+                const text = new TextDecoder().decode(new Uint8Array(memory.buffer, address, length));
+                if (fd === 1) output += text; else errors += text;
+                total += length;
+                if (output.length + errors.length > 65536) throw new Error('Probe output exceeded its limit');
+            }
+            put32(written, total);
+            return 0;
+        },
+        fd_read(fd, vectors, count, read) { if (fd !== 0) return 8; put32(read, 0); return 0; },
+        fd_fdstat_get(fd, address) {
+            if (fd > 2) return 8;
+            new Uint8Array(memory.buffer, address, 24).fill(0);
+            data().setUint8(address, 2);
+            return 0;
+        },
+        fd_fdstat_set_flags: fd => fd <= 2 ? 0 : 8,
+        fd_prestat_get: () => 8,
+        fd_prestat_dir_name: () => 8,
+        fd_close: fd => fd <= 2 ? 0 : 8,
+        fd_seek: () => 70,
+        fd_tell: () => 70,
+        fd_filestat_get: () => 8,
+        path_open: () => 76,
+        sched_yield: () => 0,
+        proc_exit(code) { throw new Exit(code); },
+    };
+    for (const name of [
+        'fd_readdir', 'fd_advise', 'fd_allocate', 'fd_datasync', 'fd_sync',
+        'fd_filestat_set_size', 'fd_filestat_set_times', 'fd_fdstat_set_rights',
+        'path_filestat_get', 'path_filestat_set_times', 'path_readlink', 'path_unlink_file',
+        'path_rename', 'path_create_directory', 'path_remove_directory', 'path_link', 'path_symlink',
+        'sock_accept', 'sock_recv', 'sock_send', 'sock_shutdown', 'poll_oneoff',
+    ]) wasi[name] = () => 76;
+    const module = await WebAssembly.compile(bytes);
+    for (const entry of WebAssembly.Module.imports(module)) {
+        if (entry.module !== 'wasi_snapshot_preview1' || typeof wasi[entry.name] !== 'function') {
+            throw new Error(`Unsupported WASI import: ${entry.module}.${entry.name}`);
+        }
+    }
+    const instance = await WebAssembly.instantiate(module, { wasi_snapshot_preview1: wasi });
+    memory = instance.exports.memory;
+    try { instance.exports._start(); }
+    catch (error) { if (!(error instanceof Exit) || error.code !== 0) throw new Error(`${error.message}: ${errors}`); }
+    if (!output.startsWith('PASS: backend=OpenSSL ') || randomCalls === 0) {
+        throw new Error(`OpenSSL probe did not pass: ${errors || output}`);
+    }
+    return { output, randomCalls, randomBytes };
+}
+
+// @license-end
diff --git a/crates/chat-crypto/src/lib.rs b/crates/chat-crypto/src/lib.rs
new file mode 100644
index 0000000..62319e2
--- /dev/null
+++ b/crates/chat-crypto/src/lib.rs
@@ -0,0 +1,223 @@
+// Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#![doc = "Experimental Sequoia post-quantum browser compatibility probe."]
+
+use anyhow::{Context, Result, ensure};
+use pgp::Profile;
+use pgp::cert::prelude::*;
+use pgp::crypto::{Password, SessionKey};
+use pgp::parse::{
+    Parse,
+    stream::{
+        DecryptionHelper, DecryptorBuilder, MessageLayer, MessageStructure, VerificationHelper,
+    },
+};
+use pgp::policy::StandardPolicy;
+use pgp::serialize::{
+    Serialize,
+    stream::{Encryptor, LiteralWriter, Message, Signer},
+};
+use pgp::types::{KeyFlags, SymmetricAlgorithm};
+use sequoia_openpgp as pgp;
+use std::io::Write;
+
+const PASSWORD: &str = "compatibility-test-only-not-a-real-secret";
+const TEXT: &[u8] = "stack-chat/v1: UTF-8 message — doan ↔ visitor".as_bytes();
+
+#[doc = "Exercises v6 PQ generation, protected-key import, signing and two-recipient encryption."]
+#[doc = "# Errors"]
+#[doc = "Returns a diagnostic if a required operation or integrity check fails."]
+pub fn compatibility_probe() -> std::result::Result<String, String> {
+    probe().map_err(|error| format!("{error:#}"))
+}
+
+fn identity() -> Result<Cert> {
+    let (cert, _revocation) = CertBuilder::new()
+        .set_profile(Profile::RFC9580)?
+        .set_cipher_suite(CipherSuite::MLDSA87_Ed448)
+        .set_primary_key_flags(KeyFlags::empty().set_certification().set_signing())
+        .add_transport_encryption_subkey()
+        .set_password(Some(Password::from(PASSWORD)))
+        .generate()?;
+    let mut encoded = Vec::new();
+    cert.as_tsk().serialize(&mut encoded)?;
+    Cert::from_bytes(&encoded)
+}
+
+fn encrypt(sender: &Cert, other: &Cert) -> Result<Vec<u8>> {
+    let policy = StandardPolicy::new();
+    let recipients = [sender, other].into_iter().flat_map(|cert| {
+        cert.keys()
+            .with_policy(&policy, None)
+            .supported()
+            .alive()
+            .revoked(false)
+            .for_transport_encryption()
+    });
+    let signer = sender
+        .primary_key()
+        .key()
+        .parts_as_secret()?
+        .clone()
+        .decrypt_secret(&Password::from(PASSWORD))?
+        .into_keypair()?;
+    let mut ciphertext = Vec::new();
+    let message = Message::new(&mut ciphertext);
+    let encrypted = Encryptor::for_recipients(message, recipients)
+        .symmetric_algo(SymmetricAlgorithm::AES256)
+        .build()?;
+    let authenticated_stream = Signer::new(encrypted, signer)?.build()?;
+    let mut literal = LiteralWriter::new(authenticated_stream).build()?;
+    literal.write_all(TEXT)?;
+    literal.finalize()?;
+    Ok(ciphertext)
+}
+
+struct Helper<'a> {
+    recipient: &'a Cert,
+    sender: &'a Cert,
+    password: &'a str,
+}
+
+impl VerificationHelper for Helper<'_> {
+    fn get_certs(&mut self, _ids: &[pgp::KeyHandle]) -> Result<Vec<Cert>> {
+        Ok(vec![self.sender.clone().strip_secret_key_material()])
+    }
+    fn check(&mut self, structure: MessageStructure<'_>) -> Result<()> {
+        let mut signed = false;
+        for layer in structure {
+            if let MessageLayer::SignatureGroup { results } = layer {
+                ensure!(!results.is_empty(), "Missing signature");
+                for result in results {
+                    result.map_err(|error| {
+                        anyhow::anyhow!("Signature verification failed: {error}")
+                    })?;
+                }
+                signed = true;
+            }
+        }
+        ensure!(signed, "Unsigned message rejected");
+        Ok(())
+    }
+}
+
+impl DecryptionHelper for Helper<'_> {
+    fn decrypt(
+        &mut self,
+        pkesks: &[pgp::packet::PKESK],
+        _skesks: &[pgp::packet::SKESK],
+        algorithm: Option<SymmetricAlgorithm>,
+        decrypt: &mut dyn FnMut(Option<SymmetricAlgorithm>, &SessionKey) -> bool,
+    ) -> Result<Option<Cert>> {
+        let policy = StandardPolicy::new();
+        let key = self
+            .recipient
+            .keys()
+            .secret()
+            .with_policy(&policy, None)
+            .for_transport_encryption()
+            .next()
+            .context("Missing encryption subkey")?
+            .key()
+            .clone();
+        let mut pair = key
+            .decrypt_secret(&Password::from(self.password))?
+            .into_keypair()?;
+        for packet in pkesks {
+            if packet
+                .decrypt(&mut pair, algorithm)
+                .is_some_and(|(cipher, key)| decrypt(cipher, &key))
+            {
+                return Ok(Some(self.recipient.clone().strip_secret_key_material()));
+            }
+        }
+        anyhow::bail!("No decryptable recipient packet")
+    }
+}
+
+fn decrypt(ciphertext: &[u8], recipient: &Cert, sender: &Cert, password: &str) -> Result<Vec<u8>> {
+    let policy = StandardPolicy::new();
+    let helper = Helper {
+        recipient,
+        sender,
+        password,
+    };
+    let mut reader =
+        DecryptorBuilder::from_bytes(ciphertext)?.with_policy(&policy, None, helper)?;
+    let mut plaintext = Vec::new();
+    std::io::copy(&mut reader, &mut plaintext)?;
+    Ok(plaintext)
+}
+
+fn probe() -> Result<String> {
+    let backend = pgp::crypto::backend();
+    ensure!(
+        backend.starts_with("OpenSSL "),
+        "Expected OpenSSL backend, got {backend}"
+    );
+    let sender = identity()?;
+    let visitor = identity()?;
+    ensure!(
+        sender.primary_key().key().pk_algo() == pgp::types::PublicKeyAlgorithm::MLDSA87_Ed448,
+        "Unexpected signing algorithm"
+    );
+    ensure!(
+        sender.primary_key().key().version() == 6,
+        "Expected v6 identity"
+    );
+    ensure!(
+        sender
+            .keys()
+            .any(|key| key.key().pk_algo() == pgp::types::PublicKeyAlgorithm::MLKEM1024_X448),
+        "Missing ML-KEM-1024+X448"
+    );
+    let ciphertext = encrypt(&sender, &visitor)?;
+    ensure!(
+        decrypt(&ciphertext, &sender, &sender, PASSWORD)? == TEXT,
+        "Sender round-trip mismatch"
+    );
+    ensure!(
+        decrypt(&ciphertext, &visitor, &sender, PASSWORD)? == TEXT,
+        "Visitor round-trip mismatch"
+    );
+    ensure!(
+        decrypt(&ciphertext, &visitor, &sender, "wrong-password").is_err(),
+        "Wrong password accepted"
+    );
+    ensure!(
+        decrypt(&ciphertext, &visitor, &visitor, PASSWORD).is_err(),
+        "Wrong signer accepted"
+    );
+    let mut altered = ciphertext;
+    let byte = altered.last_mut().context("Empty ciphertext")?;
+    *byte ^= 1;
+    ensure!(
+        decrypt(&altered, &visitor, &sender, PASSWORD).is_err(),
+        "Tampered ciphertext accepted"
+    );
+    Ok(format!(
+        "PASS: backend={backend}; RFC 9980 ML-KEM-1024+X448, ML-DSA-87+Ed448, v6 keys, protected key import, both recipients, wrong password, wrong signer, tampering"
+    ))
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn required_crypto_round_trip() -> anyhow::Result<()> {
+        super::probe()?;
+        Ok(())
+    }
+}
diff --git a/crates/chat-crypto/src/main.rs b/crates/chat-crypto/src/main.rs
new file mode 100644
index 0000000..b6749cf
--- /dev/null
+++ b/crates/chat-crypto/src/main.rs
@@ -0,0 +1,23 @@
+// Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#![doc = "Command entry point for the isolated cryptographic compatibility probe."]
+
+use std::io::{self, Write};
+
+fn main() -> io::Result<()> {
+    let result = stack_chat_crypto::compatibility_probe().map_err(io::Error::other)?;
+    writeln!(io::stdout().lock(), "{result}")
+}
diff --git a/crates/chat-crypto/tests/browser.mjs b/crates/chat-crypto/tests/browser.mjs
new file mode 100644
index 0000000..8d2a9bb
--- /dev/null
+++ b/crates/chat-crypto/tests/browser.mjs
@@ -0,0 +1,86 @@
+// Copyright (C) 2026 Doan Luu Duc Tai <doan@luuduct.ai>
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as
+// published by the Free Software Foundation, either version 3 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+import { createServer } from 'node:http';
+import { readFile } from 'node:fs/promises';
+import { resolve } from 'node:path';
+import assert from 'node:assert/strict';
+import { chromium } from '../../../.tools/browser/node_modules/playwright/index.mjs';
+
+const assets = new Map([
+    ['/wasi.mjs', [resolve('crates/chat-crypto/browser/wasi.mjs'), 'text/javascript']],
+    ['/probe.wasm', [resolve('target/wasm32-wasip1/release/stack-chat-crypto.wasm'), 'application/wasm']],
+]);
+const server = createServer(async (request, response) => {
+    response.setHeader('Cache-Control', 'no-store');
+    if (request.url === '/') {
+        response.setHeader('Content-Type', 'text/html');
+        response.end('<!doctype html><title>Local cryptographic compatibility test</title>');
+        return;
+    }
+    const asset = assets.get(request.url);
+    if (!asset) { response.writeHead(404); response.end(); return; }
+    response.setHeader('Content-Type', asset[1]);
+    response.end(await readFile(asset[0]));
+});
+await new Promise(resolveReady => server.listen(0, '127.0.0.1', resolveReady));
+const origin = `http://127.0.0.1:${server.address().port}`;
+const browser = await chromium.launch({headless: true, channel: "chromium"});
+const deadline = setTimeout(() => browser.close(), 120000);
+try {
+    const page = await browser.newPage();
+    const external = [];
+    page.on('request', request => {
+        if (!request.url().startsWith(origin + '/')) external.push(request.url());
+    });
+    await page.goto(origin);
+    const result = await page.evaluate(async () => {
+        const { runProbe } = await import('/wasi.mjs');
+        const bytes = await (await fetch('/probe.wasm', { cache: 'no-store' })).arrayBuffer();
+        const valid = await runProbe(bytes);
+        const again = await runProbe(bytes);
+        const getRandomValues = crypto.getRandomValues;
+        let rejected = false;
+        crypto.getRandomValues = () => { throw new Error('Entropy unavailable'); };
+        try { await runProbe(bytes); } catch (error) { rejected = error.message.includes("Entropy unavailable"); }
+        finally { crypto.getRandomValues = getRandomValues; }
+        const modified = new Uint8Array(bytes.slice(0));
+        const pattern = new TextEncoder().encode('random_get');
+        const offset = modified.findIndex((value, index) => pattern.every((byte, position) => modified[index + position] === byte));
+        if (offset < 0) throw new Error('Expected entropy import was not found');
+        modified.set(new TextEncoder().encode('reject_get'), offset);
+        let unknownImportRejected = false;
+        try { await runProbe(modified); }
+        catch (error) { unknownImportRejected = error.message.includes('Unsupported WASI import: wasi_snapshot_preview1.reject_get'); }
+        return { valid, again, rejected, unknownImportRejected };
+    });
+    assert.match(result.valid.output, /^PASS: backend=OpenSSL 3\.6\.5;/);
+    assert.match(result.again.output, /^PASS: backend=OpenSSL 3\.6\.5;/);
+    assert.ok(result.valid.randomCalls > 0 && result.valid.randomBytes > 0);
+    assert.ok(result.rejected, 'Unavailable browser entropy must fail closed');
+    assert.ok(result.unknownImportRejected, 'Unknown host imports must fail closed');
+    assert.deepEqual(external, []);
+    assert.deepEqual(await page.context().cookies(), []);
+    assert.equal(await page.evaluate(() => localStorage.length + sessionStorage.length), 0);
+    assert.deepEqual(await page.evaluate(async () => indexedDB.databases()), []);
+    assert.equal(await page.evaluate(async () => (await navigator.serviceWorker.getRegistrations()).length), 0);
+    console.log(result.valid.output.trim());
+    console.log(`Browser CSPRNG: ${result.valid.randomCalls} calls, ${result.valid.randomBytes} bytes; missing entropy and unknown imports rejected.`);
+    console.log('PASS: actual Chromium WASM execution; no external requests, cookies, web storage, or IndexedDB.');
+} finally {
+    clearTimeout(deadline);
+    await browser.close();
+    await new Promise(resolveClosed => server.close(resolveClosed));
+}