forked from
chadtmiller.com/pds.js
A zero-dependency AT Protocol Personal Data Server written in JavaScript
feat: add P-256 ECDSA signing via Web Crypto
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
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src/pds.js
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src/pds.js
···
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return tid
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}
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// === P-256 SIGNING ===
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// Web Crypto ECDSA with P-256 curve
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async function importPrivateKey(privateKeyBytes) {
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// PKCS#8 wrapper for raw P-256 private key
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const pkcs8Prefix = new Uint8Array([
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0x30, 0x41, 0x02, 0x01, 0x00, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86, 0x48,
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0xce, 0x3d, 0x02, 0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d, 0x03,
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0x01, 0x07, 0x04, 0x27, 0x30, 0x25, 0x02, 0x01, 0x01, 0x04, 0x20
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])
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const pkcs8 = new Uint8Array(pkcs8Prefix.length + 32)
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pkcs8.set(pkcs8Prefix)
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pkcs8.set(privateKeyBytes, pkcs8Prefix.length)
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return crypto.subtle.importKey(
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'pkcs8',
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pkcs8,
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{ name: 'ECDSA', namedCurve: 'P-256' },
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false,
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['sign']
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)
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}
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async function sign(privateKey, data) {
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const signature = await crypto.subtle.sign(
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{ name: 'ECDSA', hash: 'SHA-256' },
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privateKey,
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data
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)
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return new Uint8Array(signature)
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}
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async function generateKeyPair() {
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const keyPair = await crypto.subtle.generateKey(
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{ name: 'ECDSA', namedCurve: 'P-256' },
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true,
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['sign', 'verify']
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)
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// Export private key as raw bytes
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const privateJwk = await crypto.subtle.exportKey('jwk', keyPair.privateKey)
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const privateBytes = base64UrlDecode(privateJwk.d)
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// Export public key as compressed point
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const publicRaw = await crypto.subtle.exportKey('raw', keyPair.publicKey)
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const publicBytes = new Uint8Array(publicRaw)
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const compressed = compressPublicKey(publicBytes)
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return { privateKey: privateBytes, publicKey: compressed }
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}
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function compressPublicKey(uncompressed) {
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// uncompressed is 65 bytes: 0x04 + x(32) + y(32)
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// compressed is 33 bytes: prefix(02 or 03) + x(32)
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const x = uncompressed.slice(1, 33)
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const y = uncompressed.slice(33, 65)
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const prefix = (y[31] & 1) === 0 ? 0x02 : 0x03
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const compressed = new Uint8Array(33)
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compressed[0] = prefix
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compressed.set(x, 1)
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return compressed
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}
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function base64UrlDecode(str) {
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const base64 = str.replace(/-/g, '+').replace(/_/g, '/')
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const binary = atob(base64)
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const bytes = new Uint8Array(binary.length)
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for (let i = 0; i < binary.length; i++) {
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bytes[i] = binary.charCodeAt(i)
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}
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return bytes
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}
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function bytesToHex(bytes) {
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return Array.from(bytes).map(b => b.toString(16).padStart(2, '0')).join('')
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}
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function hexToBytes(hex) {
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const bytes = new Uint8Array(hex.length / 2)
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for (let i = 0; i < hex.length; i += 2) {
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bytes[i / 2] = parseInt(hex.substr(i, 2), 16)
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}
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return bytes
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}
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export class PersonalDataServer {
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constructor(state, env) {
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this.state = state
···
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`).toArray()
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return Response.json({ tables: tables.map(t => t.name) })
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}
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if (url.pathname === '/test/sign') {
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const kp = await generateKeyPair()
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const data = new TextEncoder().encode('test message')
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const key = await importPrivateKey(kp.privateKey)
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const sig = await sign(key, data)
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return Response.json({
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publicKey: bytesToHex(kp.publicKey),
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signature: bytesToHex(sig)
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})
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}
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return new Response('pds running', { status: 200 })
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}
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}
···
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}
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// Export utilities for testing
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export { cborEncode, createCid, cidToString, base32Encode, createTid }
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export {
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cborEncode, createCid, cidToString, base32Encode, createTid,
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generateKeyPair, importPrivateKey, sign, bytesToHex, hexToBytes
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}
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test/pds.test.js
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test/pds.test.js
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import { test, describe } from 'node:test'
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import assert from 'node:assert'
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import { cborEncode, createCid, cidToString, base32Encode, createTid } from '../src/pds.js'
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import {
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cborEncode, createCid, cidToString, base32Encode, createTid,
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generateKeyPair, importPrivateKey, sign, bytesToHex, hexToBytes
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} from '../src/pds.js'
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describe('CBOR Encoding', () => {
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test('encodes simple map', () => {
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assert.strictEqual(tids.size, 100)
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})
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})
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describe('P-256 Signing', () => {
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test('generates key pair with correct sizes', async () => {
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const kp = await generateKeyPair()
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assert.strictEqual(kp.privateKey.length, 32)
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assert.strictEqual(kp.publicKey.length, 33) // compressed
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assert.ok(kp.publicKey[0] === 0x02 || kp.publicKey[0] === 0x03)
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})
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test('can sign data with generated key', async () => {
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const kp = await generateKeyPair()
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const key = await importPrivateKey(kp.privateKey)
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const data = new TextEncoder().encode('test message')
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const sig = await sign(key, data)
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assert.strictEqual(sig.length, 64) // r (32) + s (32)
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})
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test('different messages produce different signatures', async () => {
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const kp = await generateKeyPair()
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const key = await importPrivateKey(kp.privateKey)
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const sig1 = await sign(key, new TextEncoder().encode('message 1'))
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const sig2 = await sign(key, new TextEncoder().encode('message 2'))
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assert.notDeepStrictEqual(sig1, sig2)
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})
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test('bytesToHex and hexToBytes roundtrip', () => {
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const original = new Uint8Array([0x00, 0x0f, 0xf0, 0xff, 0xab, 0xcd])
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const hex = bytesToHex(original)
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const back = hexToBytes(hex)
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assert.strictEqual(hex, '000ff0ffabcd')
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assert.deepStrictEqual(back, original)
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})
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})