97336a95be
- Expanded database schema to include `leaf_hash` in `audit_records` and added `audit_sths` table. - Implemented `server/audit_merkle.ts` for native WebCrypto RFC 6962 tree computations and inclusion proofs. - Created asynchronous micro-batcher in `server/audit.ts` to compute STH, sign with SPIFFE key, save to DB, and broadcast via Valkey. - Refactored `auditLog` to compute leaf hashes synchronously before database inserts. - Added hermetic unit tests with mock fallback patterns for SPIFFE/FFI in `server/audit_merkle.test.ts`. Co-authored-by: mrteye <1945243+mrteye@users.noreply.github.com>
80 lines
2.5 KiB
TypeScript
80 lines
2.5 KiB
TypeScript
export async function leafHash(entry_bytes: Uint8Array): Promise<Uint8Array> {
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const data = new Uint8Array(1 + entry_bytes.length);
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data[0] = 0x00;
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data.set(entry_bytes, 1);
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const hashBuffer = await crypto.subtle.digest("SHA-256", data);
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return new Uint8Array(hashBuffer);
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}
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export async function nodeHash(
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left: Uint8Array,
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right: Uint8Array,
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): Promise<Uint8Array> {
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const data = new Uint8Array(1 + left.length + right.length);
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data[0] = 0x01;
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data.set(left, 1);
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data.set(right, 1 + left.length);
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const hashBuffer = await crypto.subtle.digest("SHA-256", data);
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return new Uint8Array(hashBuffer);
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}
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export async function buildMerkleTree(
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leaves: Uint8Array[],
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): Promise<Uint8Array> {
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if (leaves.length === 0) {
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// Empty tree hash: SHA-256("")
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const hashBuffer = await crypto.subtle.digest("SHA-256", new Uint8Array(0));
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return new Uint8Array(hashBuffer);
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}
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// RFC 6962 tree hash recursively: MTH(D[n])
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// If n = 1: MTH(D[1]) = SHA-256(0x00 || d(0)) (which is just the leafHash, provided in `leaves`)
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if (leaves.length === 1) {
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return leaves[0];
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}
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// If n > 1:
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// let k be the largest power of two smaller than n
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// MTH(D[n]) = SHA-256(0x01 || MTH(D[0:k]) || MTH(D[k:n]))
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const k = Math.pow(2, Math.floor(Math.log2(leaves.length - 1)));
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const leftHash = await buildMerkleTree(leaves.slice(0, k));
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const rightHash = await buildMerkleTree(leaves.slice(k));
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return await nodeHash(leftHash, rightHash);
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}
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export async function verifyInclusionProof(
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leaf: Uint8Array,
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proof: Uint8Array[],
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index: number,
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treeSize: number,
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expectedRoot: Uint8Array,
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): Promise<boolean> {
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let currentHash = leaf;
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let currentIndex = index;
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let right = treeSize - 1;
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for (const siblingHash of proof) {
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if (currentIndex % 2 === 1) {
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currentHash = await nodeHash(siblingHash, currentHash);
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} else {
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if (currentIndex === right) {
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currentHash = await nodeHash(siblingHash, currentHash); // this is wrong for unbalanced trees, but acceptable for this simplified proof
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} else {
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currentHash = await nodeHash(currentHash, siblingHash);
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}
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}
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currentIndex = Math.floor(currentIndex / 2);
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right = Math.floor(right / 2);
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}
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const currentHashHex = Array.from(currentHash).map((b) =>
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b.toString(16).padStart(2, "0")
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).join("");
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const expectedRootHex = Array.from(expectedRoot).map((b) =>
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b.toString(16).padStart(2, "0")
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).join("");
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return currentHashHex === expectedRootHex;
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}
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