commit 73972ce951669b434108257340b6f6e52906b9ee
Author: Andre Staltz <andre@staltz.com>
Date:   Mon Jun 12 14:22:15 2023 +0300

    init

diff --git a/.github/workflows/node.js.yml b/.github/workflows/node.js.yml
new file mode 100644
index 0000000..223bd3f
--- /dev/null
+++ b/.github/workflows/node.js.yml
@@ -0,0 +1,27 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  test:
+    strategy:
+      matrix:
+        node-version: [16.x, 18.x, 20.x]
+        os: [ubuntu-latest, macos-latest, windows-latest]
+
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 2
+
+    steps:
+      - name: Checkout the repo
+        uses: actions/checkout@v2
+      - name: Set up Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+      - run: npm install
+      - run: npm test
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..44bcc03
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,4 @@
+node_modules
+.nyc_output
+coverage
+pnpm-lock.yaml
\ No newline at end of file
diff --git a/.prettierrc.yaml b/.prettierrc.yaml
new file mode 100644
index 0000000..1d2127c
--- /dev/null
+++ b/.prettierrc.yaml
@@ -0,0 +1,2 @@
+semi: false
+singleQuote: true
diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..9b34bc1
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2023 Andre 'Staltz' Medeiros
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..4ef26ce
--- /dev/null
+++ b/README.md
@@ -0,0 +1,15 @@
+# ppppp-keypair
+
+Like `ssb-keys`, but for PPPPP.
+
+API:
+
+- `generate(curve?, seed?) => Keypair {curve, public, private}`
+- `sign(keypair, msg, hmacKey?) => sig`
+- `verify(keypair, msg, sig, hmacKey?) => boolean`
+- `create(filepath, cb)`
+- `load(filepath, cb)`
+- `loadOrCreate(filepath, cb)`
+- `createSync(filepath)`
+- `loadSync(filepath)`
+- `loadOrCreateSync(filepath)`
diff --git a/lib/curves/ed25519.js b/lib/curves/ed25519.js
new file mode 100644
index 0000000..d62bde2
--- /dev/null
+++ b/lib/curves/ed25519.js
@@ -0,0 +1,101 @@
+// @ts-ignore
+const sodium = require('sodium-universal')
+const base58 = require('bs58')
+
+/**
+ * @typedef {import('.').Keypair} Keypair
+ *
+ * @typedef {import('.').KeypairPublicSlice} KeypairPublicSlice
+ *
+ * @typedef {import('.').KeypairPrivateSlice} KeypairPrivateSlice
+ */
+
+const SEEDBYTES = sodium.crypto_sign_SEEDBYTES
+const PUBLICKEYBYTES = sodium.crypto_sign_PUBLICKEYBYTES
+const SECRETKEYBYTES = sodium.crypto_sign_SECRETKEYBYTES
+
+const ed25519 = {
+  /**
+   * @param {(string | Buffer)=} seed
+   * @returns {Keypair}
+   */
+  generate(seed) {
+    let seedBuf
+    if (seed) {
+      if (Buffer.isBuffer(seed)) {
+        // prettier-ignore
+        if (seed.length !== SEEDBYTES) throw new Error(`seed must be ${SEEDBYTES} bytes`)
+        seedBuf = seed
+      } else if (typeof seed === 'string') {
+        seedBuf = Buffer.alloc(SEEDBYTES)
+        const slice = seed.substring(0, SEEDBYTES)
+        Buffer.from(slice, 'utf-8').copy(seedBuf)
+      }
+    }
+
+    const publicKeyBuf = Buffer.alloc(PUBLICKEYBYTES)
+    const secretKeyBuf = Buffer.alloc(SECRETKEYBYTES)
+    if (seedBuf) {
+      sodium.crypto_sign_seed_keypair(publicKeyBuf, secretKeyBuf, seedBuf)
+    } else {
+      sodium.crypto_sign_keypair(publicKeyBuf, secretKeyBuf)
+    }
+
+    return {
+      curve: 'ed25519',
+      public: base58.encode(publicKeyBuf),
+      private: base58.encode(secretKeyBuf),
+      _public: publicKeyBuf,
+      _private: secretKeyBuf,
+    }
+  },
+
+  /**
+   * @param {Keypair} keypair
+   * @param {{indented?: boolean}=} opts
+   */
+  toJSON(keypair, opts) {
+    const stringifiable = {
+      curve: keypair.curve,
+      public: keypair.public,
+      private: keypair.private,
+    }
+    if (opts?.indented) {
+      return JSON.stringify(stringifiable, null, 2)
+    } else {
+      return JSON.stringify(stringifiable)
+    }
+  },
+
+  /**
+   * @param {KeypairPrivateSlice} keypair
+   * @param {Buffer} message
+   * @returns {string}
+   */
+  sign(keypair, message) {
+    if (!keypair._private && !keypair.private) {
+      throw new Error(`invalid ed25519 keypair with missing private key`)
+    }
+    keypair._private ??= Buffer.from(base58.decode(keypair.private))
+    const sig = Buffer.alloc(sodium.crypto_sign_BYTES)
+    sodium.crypto_sign_detached(sig, message, keypair._private)
+    return base58.encode(sig)
+  },
+
+  /**
+   * @param {KeypairPublicSlice} keypair
+   * @param {string} sig
+   * @param {Buffer} message
+   * @returns {boolean}
+   */
+  verify(keypair, sig, message) {
+    if (!keypair._public && !keypair.public) {
+      throw new Error(`invalid ed25519 keypair with missing public key`)
+    }
+    keypair._public ??= Buffer.from(base58.decode(keypair.public))
+    const sigBuf = Buffer.from(base58.decode(sig))
+    return sodium.crypto_sign_verify_detached(sigBuf, message, keypair._public)
+  },
+}
+
+module.exports = ed25519
diff --git a/lib/curves/index.js b/lib/curves/index.js
new file mode 100644
index 0000000..8732b0a
--- /dev/null
+++ b/lib/curves/index.js
@@ -0,0 +1,60 @@
+const ed25519 = require('./ed25519')
+
+const curves = {
+  ed25519,
+}
+
+/**
+ * @typedef {keyof typeof curves} CurveName
+ *
+ * @typedef {{
+ *   curve: CurveName,
+ *   public: string,
+ *   private: string,
+ *   _public?: Buffer,
+ *   _private?: Buffer,
+ * }} Keypair
+ *
+ * @typedef {(Pick<Keypair, 'curve' | 'public'> & {_public: never}) |
+ *   (Pick<Keypair, 'curve' | '_public'> & {public: never})
+ * } KeypairPublicSlice
+ *
+ * @typedef {(Pick<Keypair, 'curve' | 'private'> & {_private: never}) |
+ *   (Pick<Keypair, 'curve' | '_private'> & {private: never})
+ * } KeypairPrivateSlice
+ *
+ * @typedef {{
+ *   generate: (seed?: Buffer | string) => Keypair,
+ *   toJSON: (keypair: Keypair, opts?: {indented?: boolean}) => string,
+ *   sign: (keypair: KeypairPrivateSlice, message: Buffer) => Buffer,
+ *   verify: (keypair: KeypairPublicSlice, message: Buffer, sig: Buffer) => boolean,
+ * }} Curve
+ */
+
+/**
+ * @param {CurveName} curveName
+ */
+function getCurve(curveName) {
+  if (!curves[curveName]) {
+    // prettier-ignore
+    throw new Error(`Unknown curve "${curveName}" out of available "${Object.keys(curves).join(',')}"`)
+  }
+  return curves[curveName]
+}
+
+/**
+ * This function generates a keypair for the given curve. The seed is optional.
+ *
+ * @param {CurveName=} curveName
+ * @param {(Buffer | string)=} seed
+ * @returns {Keypair}
+ */
+function generate(curveName, seed) {
+  const curve = getCurve(curveName ?? 'ed25519')
+  return curve.generate(seed)
+}
+
+module.exports = {
+  getCurve,
+  generate,
+}
diff --git a/lib/index.js b/lib/index.js
new file mode 100644
index 0000000..3bf72bf
--- /dev/null
+++ b/lib/index.js
@@ -0,0 +1,97 @@
+// @ts-ignore
+const sodium = require('sodium-universal')
+const base58 = require('bs58')
+const { getCurve, generate } = require('./curves')
+const StorageClass =
+  typeof window !== 'undefined'
+    ? require('./storage/browser')
+    : require('./storage/node')
+
+/**
+ * @typedef {import('./curves').Keypair} Keypair
+ * @typedef {import('./curves').KeypairPublicSlice} KeypairPublicSlice
+ * @typedef {import('./curves').KeypairPrivateSlice} KeypairPrivateSlice
+ * @typedef {import('./curves').CurveName} CurveName
+ */
+
+/**
+ * @param {any} x
+ * @returns {x is string}
+ */
+function isString(x) {
+  return typeof x === 'string'
+}
+
+/**
+ * @param {any} x
+ * @returns {x is Buffer}
+ */
+function isBuffer(x) {
+  return Buffer.isBuffer(x)
+}
+
+/**
+ * @param {Buffer} input
+ * @param {string | Buffer} key
+ * @returns {Buffer}
+ */
+function hmac(input, key) {
+  if (isString(key)) key = Buffer.from(base58.decode(key))
+  const output = Buffer.alloc(sodium.crypto_auth_BYTES)
+  sodium.crypto_auth(output, input, key)
+  return output
+}
+
+/**
+ * Takes a keypair object (where `.public` is allowed to be undefined), a
+ * message as a buffer (and an optional hmacKey) and returns a signature of the
+ * given message. The signature is string encoded in base58.
+ *
+ * @param {KeypairPrivateSlice} keypair
+ * @param {Buffer} msg
+ * @param {Buffer | string | undefined} hmacKey
+ * @returns {string}
+ */
+function sign(keypair, msg, hmacKey) {
+  if (!isBuffer(msg)) throw new Error('Signable message should be buffer')
+  const curve = getCurve(keypair.curve)
+
+  if (hmacKey) msg = hmac(msg, hmacKey)
+
+  return curve.sign(keypair, msg)
+}
+
+/**
+ * Takes a keypair object (where `private` is allowed to be undefined), a
+ * message buffer and its signature string (and an optional hmacKey), and
+ * returns true if the signature is valid for the message, false otherwise.
+ *
+ * @param {KeypairPublicSlice} keypair
+ * @param {Buffer} msg
+ * @param {string} sig
+ * @param {Buffer | string | undefined} hmacKey
+ * @returns {boolean}
+ */
+function verify(keypair, msg, sig, hmacKey) {
+  if (!isString(sig)) throw new Error('sig should be string')
+  if (!isBuffer(msg)) throw new Error('Signed message should be buffer')
+  const curve = getCurve(keypair.curve)
+
+  if (hmacKey) msg = hmac(msg, hmacKey)
+
+  return curve.verify(keypair, sig, msg)
+}
+
+const storage = new StorageClass()
+
+module.exports = {
+  generate,
+  sign,
+  verify,
+  create: storage.create.bind(storage),
+  load: storage.load.bind(storage),
+  createSync: storage.createSync.bind(storage),
+  loadSync: storage.loadSync.bind(storage),
+  loadOrCreate: storage.loadOrCreate.bind(storage),
+  loadOrCreateSync: storage.loadOrCreateSync.bind(storage),
+}
diff --git a/lib/storage/browser.js b/lib/storage/browser.js
new file mode 100644
index 0000000..1cfa2a1
--- /dev/null
+++ b/lib/storage/browser.js
@@ -0,0 +1,74 @@
+const { generate, getCurve } = require('../curves')
+const Storage = require('./common')
+
+/**
+ * @typedef {import('../curves').Keypair} Keypair
+ *
+ * @typedef {(...args: [Error] | [null, Keypair]) => void} Callback
+ */
+
+class BrowserStorage extends Storage {
+  constructor() {
+    super()
+  }
+
+  /**
+   * @param {string} identifier
+   * @returns {Keypair}
+   */
+  createSync(identifier) {
+    const keypair = generate()
+    const curve = getCurve(keypair.curve)
+    const jsonStr = curve.toJSON(keypair, { indented: false })
+    localStorage.setItem(identifier, jsonStr)
+    return keypair
+  }
+
+  /**
+   * @param {string} identifier
+   * @returns {Keypair}
+   */
+  loadSync(identifier) {
+    const item = localStorage.getItem(identifier)
+    if (!item) {
+      throw new Error(`No keypair found at localStorage "${identifier}"`)
+    }
+    try {
+      return JSON.parse(item)
+    } catch {
+      throw new Error(`Malformed keypair JSON in localStorage ${identifier}`)
+    }
+  }
+
+  /**
+   * @param {string} identifier
+   * @param {Callback} cb
+   */
+  create(identifier, cb) {
+    let keypair
+    try {
+      keypair = this.createSync(identifier)
+    } catch (err) {
+      cb(/** @type {Error} */ (err))
+      return
+    }
+    cb(null, keypair)
+  }
+
+  /**
+   * @param {string} identifier
+   * @param {Callback} cb
+   */
+  load(identifier, cb) {
+    let keypair
+    try {
+      keypair = this.loadSync(identifier)
+    } catch (err) {
+      cb(/** @type {Error} */ (err))
+      return
+    }
+    cb(null, keypair)
+  }
+}
+
+module.exports = BrowserStorage
diff --git a/lib/storage/common.js b/lib/storage/common.js
new file mode 100644
index 0000000..5ee1ea2
--- /dev/null
+++ b/lib/storage/common.js
@@ -0,0 +1,66 @@
+/**
+ * @typedef {import('../curves').Keypair} Keypair
+ *
+ * @typedef {import('../curves').CurveName} CurveName
+ *
+ * @typedef {(...args: [Error] | [null, Keypair]) => void} Callback
+ */
+
+class Storage {
+  /**
+   * @param {string} identifier
+   * @param {Callback} cb
+   */
+  load(identifier, cb) {
+    throw new Error('load() missing an implementation')
+  }
+
+  /**
+   * @param {string} identifier
+   * @param {Callback} cb
+   */
+  create(identifier, cb) {
+    throw new Error('create() missing an implementation')
+  }
+
+  /**
+   * @param {string} identifier
+   * @returns {Keypair}
+   */
+  loadSync(identifier) {
+    throw new Error('loadSync() missing an implementation')
+  }
+
+  /**
+   * @param {string} identifier
+   * @returns {Keypair}
+   */
+  createSync(identifier) {
+    throw new Error('createSync() missing an implementation')
+  }
+
+  /**
+   * @param {string} identifier
+   * @param {Callback} cb
+   */
+  loadOrCreate(identifier, cb) {
+    this.load(identifier, (err, keypair) => {
+      if (!err) return cb(null, keypair)
+      else this.create(identifier, cb)
+    })
+  }
+
+  /**
+   * @param {string} identifier
+   * @returns {Keypair}
+   */
+  loadOrCreateSync(identifier) {
+    try {
+      return this.loadSync(identifier)
+    } catch {
+      return this.createSync(identifier)
+    }
+  }
+}
+
+module.exports = Storage
diff --git a/lib/storage/node.js b/lib/storage/node.js
new file mode 100644
index 0000000..e954830
--- /dev/null
+++ b/lib/storage/node.js
@@ -0,0 +1,126 @@
+const fs = require('node:fs')
+const path = require('node:path')
+const { mkdirp } = require('mkdirp')
+const { generate, getCurve } = require('../curves')
+const Storage = require('./common')
+
+/**
+ * @typedef {import('../curves').Keypair} Keypair
+ *
+ * @typedef {(...args: [Error] | [null, Keypair]) => void} Callback
+ */
+
+class NodeStorage extends Storage {
+  constructor() {
+    super()
+  }
+
+  /** @type {BufferEncoding} */
+  #fileEncoding = 'ascii'
+
+  /** @type {fs.WriteFileOptions} */
+  #fileWriteOpts = { mode: 0x100, flag: 'wx', encoding: this.#fileEncoding }
+
+  /**
+   * @param {Keypair} keypair
+   * @returns {string}
+   */
+  #toFileContents(keypair) {
+    const curve = getCurve(keypair.curve)
+    const jsonStr = curve.toJSON(keypair, { indented: true })
+
+    return `# WARNING: Never show this to anyone.
+# WARNING: Never edit it or use it on multiple devices at once.
+#
+# This is your SECRET, it gives you magical powers. With your secret you can
+# sign your messages so that your friends can verify that the messages came
+# from you. If anyone learns your secret, they can use it to impersonate you.
+#
+# If you use this secret on more than one device you will create a fork and
+# your friends will stop replicating your content.
+#
+${jsonStr}
+#
+# The only part of this file that's safe to share is your public name:
+#
+#   ${keypair.public}`
+  }
+
+  /**
+   * @param {string} contents
+   * @return {Keypair}
+   */
+  #fromFileContents(contents) {
+    const json = contents
+      .replace(/\s*#[^\n]*/g, '')
+      .split('\n')
+      .filter((x) => !!x)
+      .join('')
+
+    try {
+      const keypair = JSON.parse(json)
+      return keypair
+    } catch {
+      throw new Error(`Malformed keypair JSON in file contents`)
+    }
+  }
+
+  /**
+   * @param {string} filename
+   * @returns {Keypair}
+   */
+  createSync(filename) {
+    const keypair = generate()
+    const fileContents = this.#toFileContents(keypair)
+    mkdirp.sync(path.dirname(filename))
+    fs.writeFileSync(filename, fileContents, this.#fileWriteOpts)
+    return keypair
+  }
+
+  /**
+   * @param {string} filename
+   * @returns {Keypair}
+   */
+  loadSync(filename) {
+    const fileContents = fs.readFileSync(filename, this.#fileEncoding)
+    const keypair = this.#fromFileContents(fileContents)
+    return keypair
+  }
+
+  /**
+   * @param {string} filename
+   * @param {Callback} cb
+   */
+  create(filename, cb) {
+    const keypair = generate()
+    const fileContents = this.#toFileContents(keypair)
+    mkdirp(path.dirname(filename)).then(() => {
+      fs.writeFile(filename, fileContents, this.#fileWriteOpts, (err) => {
+        if (err) cb(err)
+        else cb(null, keypair)
+      })
+    }, cb)
+  }
+
+  /**
+   * @param {string} filename
+   * @param {Callback} cb
+   */
+  load(filename, cb) {
+    fs.readFile(filename, this.#fileEncoding, (err, fileContents) => {
+      if (err) return cb(err)
+
+      /** @type {Keypair} */
+      let keypair
+      try {
+        keypair = this.#fromFileContents(fileContents)
+      } catch (err) {
+        cb(/** @type {Error} */ (err))
+        return
+      }
+      cb(null, keypair)
+    })
+  }
+}
+
+module.exports = NodeStorage
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..b980d77
--- /dev/null
+++ b/package.json
@@ -0,0 +1,49 @@
+{
+  "name": "ppppp-keypair",
+  "description": "Keyfile operations for PPPPP",
+  "version": "0.0.1",
+  "homepage": "https://github.com/staltz/ppppp-keypair",
+  "repository": {
+    "type": "git",
+    "url": "git://github.com/staltz/ppppp-keypair.git"
+  },
+  "author": "Andre 'Staltz' Medeiros <contact@staltz.com>",
+  "license": "MIT",
+  "main": "lib/index.js",
+  "files": [
+    "lib/**/*"
+  ],
+  "engines": {
+    "node": ">=16"
+  },
+  "exports": {
+    ".": {
+      "require": "./lib/index.js"
+    }
+  },
+  "dependencies": {
+    "bs58": "^5.0.0",
+    "sodium-universal": "^4.0.0",
+    "mkdirp": "~3.0.1"
+  },
+  "devDependencies": {
+    "@types/node": "^20.2.5",
+    "c8": "^7.11.0",
+    "husky": "^4.3.0",
+    "prettier": "^2.6.2",
+    "pretty-quick": "^3.1.3",
+    "typescript": "^5.0.2"
+  },
+  "scripts": {
+    "build": "tsc",
+    "test": "node --test",
+    "format-code": "prettier --write \"*.js\" \"(test|lib)/*.js\"",
+    "format-code-staged": "pretty-quick --staged --pattern \"*.js\" --pattern \"(test|lib)/*.js\"",
+    "coverage": "c8 --reporter=lcov npm run test"
+  },
+  "husky": {
+    "hooks": {
+      "pre-commit": "pretty-quick --staged"
+    }
+  }
+}
diff --git a/test/fs.test.js b/test/fs.test.js
new file mode 100644
index 0000000..44f9da4
--- /dev/null
+++ b/test/fs.test.js
@@ -0,0 +1,130 @@
+const test = require('node:test')
+const assert = require('node:assert')
+const fs = require('fs')
+const os = require('os')
+const path = require('path')
+const Keypair = require('../lib/index')
+
+const keyPath = path.join(os.tmpdir(), `ppppp-keypair-${Date.now()}`)
+
+test('loadSync()', (t) => {
+  const keypair = Keypair.generate('ed25519')
+  fs.writeFileSync(keyPath, JSON.stringify(keypair))
+
+  const keypair2 = Keypair.loadSync(keyPath)
+  assert.ok(keypair2.public)
+  assert.equal(keypair2.public, keypair.public)
+  fs.unlinkSync(keyPath)
+})
+
+test('load()', (t, done) => {
+  const keypair = Keypair.generate('ed25519')
+  fs.writeFileSync(keyPath, JSON.stringify(keypair))
+
+  Keypair.load(keyPath, (err, keypair2) => {
+    assert.ifError(err)
+    assert.ok(keypair2.public)
+    assert.equal(keypair2.public, keypair.public)
+    fs.unlinkSync(keyPath)
+    done()
+  })
+})
+
+test('create() then load()', (t, done) => {
+  Keypair.create(keyPath, (err, k1) => {
+    assert.ifError(err)
+    Keypair.load(keyPath, (err, k2) => {
+      assert.ifError(err)
+      assert.equal(k1.private, k2.private)
+      assert.equal(k1.public, k2.public)
+      fs.unlinkSync(keyPath)
+      done()
+    })
+  })
+})
+
+test('createSync() then loadSync()', (t) => {
+  const k1 = Keypair.createSync(keyPath)
+  const k2 = Keypair.loadSync(keyPath)
+  assert.equal(k1.private, k2.private)
+  assert.equal(k1.public, k2.public)
+  fs.unlinkSync(keyPath)
+})
+
+test('create()/createSync() avoid overwriting existing keys', (t, done) => {
+  fs.writeFileSync(keyPath, 'this file intentionally left blank', 'utf8')
+  assert.throws(() => {
+    Keypair.createSync(keyPath)
+  })
+  Keypair.create(keyPath, (err) => {
+    assert.ok(err)
+    done()
+  })
+})
+
+test('loadOrCreate() can load', (t, done) => {
+  const keyPath = path.join(os.tmpdir(), `ssb-keys-1-${Date.now()}`)
+  const keypair = Keypair.generate('ed25519')
+  fs.writeFileSync(keyPath, JSON.stringify(keypair))
+
+  Keypair.loadOrCreate(keyPath, (err, keypair2) => {
+    assert.ifError(err)
+    assert.ok(keypair2.public)
+    assert.equal(keypair2.public, keypair.public)
+    fs.unlinkSync(keyPath)
+    done()
+  })
+})
+
+test('loadOrCreate() can create', (t, done) => {
+  const keyPath = path.join(os.tmpdir(), `ssb-keys-2-${Date.now()}`)
+  assert.equal(fs.existsSync(keyPath), false)
+
+  Keypair.loadOrCreate(keyPath, (err, keypair) => {
+    assert.ifError(err)
+    assert.ok(keypair.public.length > 20, 'keys.public is a long string')
+    assert.ok(keypair.private.length > 20, 'keys.private is a long string')
+    assert.equal(typeof keypair.curve, 'string', 'keys.curve is a string')
+    fs.unlinkSync(keyPath)
+    done()
+  })
+})
+
+test('loadOrCreateSync() can load', (t) => {
+  const keyPath = path.join(os.tmpdir(), `ssb-keys-3-${Date.now()}`)
+  const keypair = Keypair.generate('ed25519')
+  fs.writeFileSync(keyPath, JSON.stringify(keypair))
+
+  const keypair2 = Keypair.loadOrCreateSync(keyPath)
+  assert.ok(keypair2.public)
+  assert.equal(keypair2.public, keypair.public)
+  fs.unlinkSync(keyPath)
+})
+
+test('loadOrCreateSync() can create', (t) => {
+  const keyPath = path.join(os.tmpdir(), `ssb-keys-4-${Date.now()}`)
+  assert.equal(fs.existsSync(keyPath), false)
+
+  const keypair = Keypair.loadOrCreateSync(keyPath)
+  assert.ok(keypair.public.length > 20, 'keys.public is a long string')
+  assert.ok(keypair.private.length > 20, 'keys.private is a long string')
+  assert.ok(keypair.curve, 'keys.curve is a string')
+  fs.unlinkSync(keyPath)
+})
+
+test('loadOrCreate() doesnt create dir for fully-specified path', (t, done) => {
+  const keyPath = path.join(os.tmpdir(), `ssb-keys-5-${Date.now()}`)
+  assert.equal(fs.existsSync(keyPath), false)
+
+  Keypair.loadOrCreate(keyPath, (err) => {
+    assert.ifError(err)
+    assert.ok(fs.lstatSync(keyPath).isFile())
+
+    Keypair.loadOrCreate(keyPath, (err, keypair) => {
+      assert.ifError(err)
+      assert.ok(keypair.public.length > 20)
+      fs.unlinkSync(keyPath)
+      done()
+    })
+  })
+})
diff --git a/test/generate.test.js b/test/generate.test.js
new file mode 100644
index 0000000..88e442a
--- /dev/null
+++ b/test/generate.test.js
@@ -0,0 +1,37 @@
+const test = require('node:test')
+const assert = require('node:assert')
+const Keypair = require('../lib/index')
+
+test('generate() default', (t) => {
+  const keypair = Keypair.generate()
+  assert.equal(keypair.curve, 'ed25519')
+  assert.equal(typeof keypair.public, 'string')
+  assert.equal(typeof keypair.private, 'string')
+  assert.equal(Buffer.isBuffer(keypair._public), true)
+  assert.equal(Buffer.isBuffer(keypair._private), true)
+  assert.deepEqual(Object.keys(keypair), [
+    'curve',
+    'public',
+    'private',
+    '_public',
+    '_private',
+  ])
+})
+
+test('generate() with ed25519 curve', (t) => {
+  const keypair = Keypair.generate('ed25519')
+  assert.equal(keypair.curve, 'ed25519')
+  assert.equal(typeof keypair.public, 'string')
+  assert.equal(typeof keypair.private, 'string')
+})
+
+test('generate() with unknown curve', (t) => {
+  assert.throws(() => {
+    Keypair.generate('foobar')
+  }, /Unknown curve "foobar"/)
+})
+
+test('generate() with seed', (t) => {
+  const keypair = Keypair.generate('ed25519', 'alice')
+  assert.equal(keypair.public, '4mjQ5aJu378cEu6TksRG3uXAiKFiwGjYQtWAjfVjDAJW')
+})
\ No newline at end of file
diff --git a/test/signing.test.js b/test/signing.test.js
new file mode 100644
index 0000000..43f1664
--- /dev/null
+++ b/test/signing.test.js
@@ -0,0 +1,33 @@
+const test = require('node:test')
+const assert = require('node:assert')
+const Keypair = require('../lib/index')
+const crypto = require('crypto')
+
+test('sign()/verify() does not work on strings', (t) => {
+  const str = 'ppppp'
+  const keypair = Keypair.generate()
+  assert.throws(() => {
+    Keypair.sign(keypair, str)
+  })
+})
+
+test('sign()/verify() a buffer without hmac key', (t) => {
+  const buf = Buffer.from('ppppp')
+  const keypair = Keypair.generate()
+  const sig = Keypair.sign(keypair, buf)
+  assert.ok(sig)
+  const { public, curve } = keypair
+  assert.ok(Keypair.verify({ public, curve }, buf, sig))
+})
+
+test('sign()/verify a buffer with hmac key', (t) => {
+  const str = Buffer.from('ppppp')
+  const keypair = Keypair.generate()
+  const hmac_key = crypto.randomBytes(32)
+  const hmac_key2 = crypto.randomBytes(32)
+
+  const sig = Keypair.sign(keypair, str, hmac_key)
+  assert.ok(sig)
+  assert.equal(Keypair.verify(keypair, str, sig, hmac_key), true)
+  assert.equal(Keypair.verify(keypair, str, sig, hmac_key2), false)
+})
diff --git a/tsconfig.json b/tsconfig.json
new file mode 100644
index 0000000..f6eb639
--- /dev/null
+++ b/tsconfig.json
@@ -0,0 +1,15 @@
+{
+  "include": ["lib/**/*.js"],
+  "exclude": ["coverage/", "node_modules/", "test/"],
+  "compilerOptions": {
+    "checkJs": true,
+    "noEmit": true,
+    "exactOptionalPropertyTypes": true,
+    "forceConsistentCasingInFileNames": true,
+    "lib": ["es2021", "dom"],
+    "module": "node16",
+    "skipLibCheck": true,
+    "strict": true,
+    "target": "es2021"
+  }
+}
\ No newline at end of file