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| author | murilo ijanc | 2026-03-24 21:45:05 -0300 |
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| committer | murilo ijanc | 2026-03-24 21:45:05 -0300 |
| commit | 01c17c68277ff88fab812920732d9bbe9e6bb571 (patch) | |
| tree | 035398ae34263b981b621c6275835d2cc6847d57 /news/phase4-wasm-browser-verification/index.html | |
| parent | f186b71ca51e83837db60de13322394bb5e6d348 (diff) | |
| download | website-01c17c68277ff88fab812920732d9bbe9e6bb571.tar.gz | |
Remove old Zola-generated content, keep only the essential
landing page with about, contact, and license sections.
Diffstat (limited to 'news/phase4-wasm-browser-verification/index.html')
| -rw-r--r-- | news/phase4-wasm-browser-verification/index.html | 192 |
1 files changed, 0 insertions, 192 deletions
diff --git a/news/phase4-wasm-browser-verification/index.html b/news/phase4-wasm-browser-verification/index.html deleted file mode 100644 index 571e094..0000000 --- a/news/phase4-wasm-browser-verification/index.html +++ /dev/null @@ -1,192 +0,0 @@ -<!DOCTYPE html> -<html lang="en"> -<head> - <meta charset="utf-8"> - <meta name="viewport" content="width=device-width, initial-scale=1"> - <title>Phase 4: Verify Without Installing Anything — Tesseras</title> - <meta name="description" content="Tesseras now compiles to WebAssembly — anyone can verify a tessera's integrity and authenticity directly in the browser, with no software to install."> - <!-- Open Graph --> - <meta property="og:type" content="article"> - <meta property="og:title" content="Phase 4: Verify Without Installing Anything"> - <meta property="og:description" content="Tesseras now compiles to WebAssembly — anyone can verify a tessera's integrity and authenticity directly in the browser, with no software to install."> - <meta property="og:image" content="https://tesseras.net/images/social.jpg"> - <meta property="og:image:width" content="1200"> - <meta property="og:image:height" content="630"> - <meta property="og:site_name" content="Tesseras"> - <!-- Twitter Card --> - <meta name="twitter:card" content="summary_large_image"> - <meta name="twitter:title" content="Phase 4: Verify Without Installing Anything"> - <meta name="twitter:description" content="Tesseras now compiles to WebAssembly — anyone can verify a tessera's integrity and authenticity directly in the browser, with no software to install."> - <meta name="twitter:image" content="https://tesseras.net/images/social.jpg"> - <link rel="stylesheet" href="https://tesseras.net/style.css?h=21f0f32121928ee5c690"> - - - <link rel="alternate" type="application/atom+xml" title="Tesseras" href="https://tesseras.net/atom.xml"> - - - <link rel="icon" type="image/png" sizes="32x32" href="https://tesseras.net/images/favicon.png?h=be4e123a23393b1a027d"> - -</head> -<body> - <header> - <h1> - <a href="https://tesseras.net/"> - <img src="https://tesseras.net/images/logo-64.png?h=c1b8d0c4c5f93b49d40b" alt="Tesseras" width="40" height="40" class="logo"> - Tesseras - </a> - </h1> - <nav> - - <a href="https://tesseras.net/about/">About</a> - <a href="https://tesseras.net/news/">News</a> - <a href="https://tesseras.net/releases/">Releases</a> - <a href="https://tesseras.net/faq/">FAQ</a> - <a href="https://tesseras.net/subscriptions/">Subscriptions</a> - <a href="https://tesseras.net/contact/">Contact</a> - - </nav> - <nav class="lang-switch"> - - <strong>English</strong> | <a href="/pt-br/news/phase4-wasm-browser-verification/">Português</a> - - </nav> - </header> - - <main> - -<article> - <h2>Phase 4: Verify Without Installing Anything</h2> - <p class="news-date">2026-02-15</p> - <p>Trust shouldn't require installing software. If someone sends you a tessera — a -bundle of preserved memories — you should be able to verify it's genuine and -unmodified without downloading an app, creating an account, or trusting a -server. That's what <code>tesseras-wasm</code> delivers: drag a tessera archive into a web -page, and cryptographic verification happens entirely in your browser.</p> -<h2 id="what-was-built">What was built</h2> -<p><strong>tesseras-wasm</strong> — A Rust crate that compiles to WebAssembly via wasm-pack, -exposing four stateless functions to JavaScript. The crate depends on -<code>tesseras-core</code> for manifest parsing and calls cryptographic primitives directly -(blake3, ed25519-dalek) rather than depending on <code>tesseras-crypto</code>, which pulls -in C-based post-quantum libraries that don't compile to -<code>wasm32-unknown-unknown</code>.</p> -<p><code>parse_manifest</code> takes raw MANIFEST bytes (UTF-8 plain text, not MessagePack), -delegates to <code>tesseras_core::manifest::Manifest::parse()</code>, and returns a JSON -string with the creator's Ed25519 public key, signature file paths, and a list -of files with their expected BLAKE3 hashes, sizes, and MIME types. Internal -structs (<code>ManifestJson</code>, <code>CreatorPubkey</code>, <code>SignatureFiles</code>, <code>FileEntry</code>) are -serialized with serde_json. The ML-DSA public key and signature file fields are -present in the JSON contract but set to <code>null</code> — ready for when post-quantum -signing is implemented on the native side.</p> -<p><code>hash_blake3</code> computes a BLAKE3 hash of arbitrary bytes and returns a -64-character hex string. It's called once per file in the tessera to verify -integrity against the MANIFEST.</p> -<p><code>verify_ed25519</code> takes a message, a 64-byte signature, and a 32-byte public key, -constructs an <code>ed25519_dalek::VerifyingKey</code>, and returns whether the signature -is valid. Length validation returns descriptive errors ("Ed25519 public key must -be 32 bytes") rather than panicking.</p> -<p><code>verify_ml_dsa</code> is a stub that returns an error explaining ML-DSA verification -is not yet available. This is deliberate: the <code>ml-dsa</code> crate on crates.io is -v0.1.0-rc.7 (pre-release), and <code>tesseras-crypto</code> uses <code>pqcrypto-dilithium</code> -(C-based CRYSTALS-Dilithium) which is byte-incompatible with FIPS 204 ML-DSA. -Both sides need to use the same pure Rust implementation before -cross-verification works. Ed25519 verification is sufficient — every tessera is -Ed25519-signed.</p> -<p>All four functions use a two-layer pattern for testability: inner functions -return <code>Result<T, String></code> and are tested natively, while thin <code>#[wasm_bindgen]</code> -wrappers convert errors to <code>JsError</code>. This avoids <code>JsError::new()</code> panicking on -non-WASM targets during testing.</p> -<p>The compiled WASM binary is 109 KB raw and 44 KB gzipped — well under the 200 KB -budget. wasm-opt applies <code>-Oz</code> optimization after wasm-pack builds with -<code>opt-level = "z"</code>, LTO, and single codegen unit.</p> -<p><strong>@tesseras/verify</strong> — A TypeScript npm package (<code>crates/tesseras-wasm/js/</code>) -that orchestrates browser-side verification. The public API is a single -function:</p> -<pre><code data-lang="typescript">async function verifyTessera( - archive: Uint8Array, - onProgress?: (current: number, total: number, file: string) => void -): Promise<VerificationResult> -</code></pre> -<p>The <code>VerificationResult</code> type provides everything a UI needs: overall validity, -tessera hash, creator public keys, signature status (valid/invalid/missing for -both Ed25519 and ML-DSA), per-file integrity results with expected and actual -hashes, a list of unexpected files not in the MANIFEST, and an errors array.</p> -<p>Archive unpacking (<code>unpack.ts</code>) handles three formats: gzip-compressed tar -(detected by <code>\x1f\x8b</code> magic bytes, decompressed with fflate then parsed as -tar), ZIP (<code>PK\x03\x04</code> magic, unpacked with fflate's <code>unzipSync</code>), and raw tar -(<code>ustar</code> at offset 257). A <code>normalizePath</code> function strips the leading -<code>tessera-<hash>/</code> prefix so internal paths match MANIFEST entries.</p> -<p>Verification runs in a Web Worker (<code>worker.ts</code>) to keep the UI thread -responsive. The worker initializes the WASM module, unpacks the archive, parses -the MANIFEST, verifies the Ed25519 signature against the creator's public key, -then hashes each file with BLAKE3 and compares against expected values. Progress -messages stream back to the main thread after each file. If any signature is -invalid, verification stops early without hashing files — failing fast on the -most critical check.</p> -<p>The archive is transferred to the worker with zero-copy -(<code>worker.postMessage({ type: "verify", archive }, [archive.buffer])</code>) to avoid -duplicating potentially large tessera files in memory.</p> -<p><strong>Build pipeline</strong> — Three new justfile targets: <code>wasm-build</code> runs wasm-pack -with <code>--target web --release</code> and optimizes with wasm-opt; <code>wasm-size</code> reports -raw and gzipped binary size; <code>test-wasm</code> runs the native test suite.</p> -<p><strong>Tests</strong> — 9 native unit tests cover BLAKE3 hashing (empty input, known value), -Ed25519 verification (valid signature, invalid signature, wrong key, bad key -length), and MANIFEST parsing (valid manifest, invalid UTF-8, garbage input). 3 -WASM integration tests run in headless Chrome via -<code>wasm-pack test --headless --chrome</code>, verifying that <code>hash_blake3</code>, -<code>verify_ed25519</code>, and <code>parse_manifest</code> work correctly when compiled to -<code>wasm32-unknown-unknown</code>.</p> -<h2 id="architecture-decisions">Architecture decisions</h2> -<ul> -<li><strong>No tesseras-crypto dependency</strong>: the WASM crate calls blake3 and -ed25519-dalek directly. <code>tesseras-crypto</code> depends on <code>pqcrypto-kyber</code> (C-based -ML-KEM via pqcrypto-traits) which requires a C compiler toolchain and doesn't -target wasm32. By depending only on pure Rust crates, the WASM build has zero -C dependencies and compiles cleanly to WebAssembly.</li> -<li><strong>ML-DSA deferred, not faked</strong>: rather than silently skipping post-quantum -verification, the stub returns an explicit error. This ensures that if a -tessera contains an ML-DSA signature, the verification result will report -<code>ml_dsa: "missing"</code> rather than pretending it was checked. The JS orchestrator -handles this gracefully — a tessera is valid if Ed25519 passes and ML-DSA is -missing (not yet implemented on either side).</li> -<li><strong>Inner function pattern</strong>: <code>JsError</code> cannot be constructed on non-WASM -targets (it panics). Splitting each function into -<code>foo_inner() -> Result<T, String></code> and <code>foo() -> Result<T, JsError></code> lets the -native test suite exercise all logic without touching JavaScript types. The -WASM integration tests in headless Chrome test the full <code>#[wasm_bindgen]</code> -surface.</li> -<li><strong>Web Worker isolation</strong>: cryptographic operations (especially BLAKE3 over -large media files) can take hundreds of milliseconds. Running in a Worker -prevents UI jank. The streaming progress protocol -(<code>{ type: "progress", current, total, file }</code>) lets the UI show a progress bar -during verification of tesseras with many files.</li> -<li><strong>Zero-copy transfer</strong>: <code>archive.buffer</code> is transferred to the Worker, not -copied. For a 50 MB tessera archive, this avoids doubling memory usage during -verification.</li> -<li><strong>Plain text MANIFEST, not MessagePack</strong>: the WASM crate parses the same -plain-text MANIFEST format as the CLI. This is by design — the MANIFEST is the -tessera's Rosetta Stone, readable by anyone with a text editor. The -<code>rmp-serde</code> dependency in the Cargo.toml is not used and will be removed.</li> -</ul> -<h2 id="what-comes-next">What comes next</h2> -<ul> -<li><strong>Phase 4: Resilience and Scale</strong> — OS packaging (Alpine, Arch, Debian, -FreeBSD, OpenBSD), CI on SourceHut and GitHub Actions, security audits, -browser-based tessera explorer at tesseras.net using @tesseras/verify</li> -<li><strong>Phase 5: Exploration and Culture</strong> — Public tessera browser by -era/location/theme/language, institutional curation, genealogy integration, -physical media export (M-DISC, microfilm, acid-free paper with QR)</li> -</ul> -<p>Verification no longer requires trust in software. A tessera archive dropped -into a browser is verified with the same cryptographic rigor as the CLI — same -BLAKE3 hashes, same Ed25519 signatures, same MANIFEST parser. The difference is -that now anyone can do it.</p> - -</article> - - </main> - - <footer> - <p>© 2026 Tesseras Project. <a href="/atom.xml">News Feed</a> · <a href="https://git.sr.ht/~ijanc/tesseras">Source</a></p> - </footer> -</body> -</html> |