feat: key exchange with jsrsasign (#115)

* feat: export/import password protected RSA key

* docs: crypto.key.import

* test: import with wrong password

* fix: lint

* test: importing openssl keys

* just to trigger circle with new ubuntu

* feat: get the RSA key id

* feat: get the ED 25519 key id

* feat: pbkdf2

* fix(pbkdf2): base64 has more chars to guess than hex

* chore: update deps

src/keys/ed25519-class.js

@@ -2,6 +2,7 @@
 
 const multihashing = require('multihashing-async')
 const protobuf = require('protons')
+const bs58 = require('bs58')
 
 const crypto = require('./ed25519')
 const pbm = protobuf(require('./keys.proto'))
@@ -77,6 +78,25 @@ class Ed25519PrivateKey {
     ensure(callback)
     multihashing(this.bytes, 'sha2-256', callback)
   }
+
+  /**
+   * Gets the ID of the key.
+   *
+   * The key id is the base58 encoding of the SHA-256 multihash of its public key.
+   * The public key is a protobuf encoding containing a type and the DER encoding
+   * of the PKCS SubjectPublicKeyInfo.
+   *
+   * @param {function(Error, id)} callback
+   * @returns {undefined}
+   */
+  id (callback) {
+    this.public.hash((err, hash) => {
+      if (err) {
+        return callback(err)
+      }
+      callback(null, bs58.encode(hash))
+    })
+  }
 }
 
 function unmarshalEd25519PrivateKey (bytes, callback) {

src/keys/index.js

@@ -2,6 +2,8 @@
 
 const protobuf = require('protons')
 const keysPBM = protobuf(require('./keys.proto'))
+const jsrsasign = require('jsrsasign')
+const KEYUTIL = jsrsasign.KEYUTIL
 
 exports = module.exports
 
@@ -115,3 +117,17 @@ exports.marshalPrivateKey = (key, type) => {
 
   return key.bytes
 }
+
+exports.import = (pem, password, callback) => {
+  try {
+    const key = KEYUTIL.getKey(pem, password)
+    if (key instanceof jsrsasign.RSAKey) {
+      const jwk = KEYUTIL.getJWKFromKey(key)
+      return supportedKeys.rsa.fromJwk(jwk, callback)
+    } else {
+      throw new Error(`Unknown key type '${key.prototype.toString()}'`)
+    }
+  } catch (err) {
+    callback(err)
+  }
+}

src/keys/rsa-browser.js

@@ -105,9 +105,7 @@ function derivePublicFromPrivate (jwKey) {
     {
       kty: jwKey.kty,
       n: jwKey.n,
-      e: jwKey.e,
-      alg: jwKey.alg,
-      kid: jwKey.kid
+      e: jwKey.e
     },
     {
       name: 'RSASSA-PKCS1-v1_5',

src/keys/rsa-class.js

@@ -2,9 +2,12 @@
 
 const multihashing = require('multihashing-async')
 const protobuf = require('protons')
+const bs58 = require('bs58')
 
 const crypto = require('./rsa')
 const pbm = protobuf(require('./keys.proto'))
+const KEYUTIL = require('jsrsasign').KEYUTIL
+const setImmediate = require('async/setImmediate')
 
 class RsaPublicKey {
   constructor (key) {
@@ -89,6 +92,60 @@ class RsaPrivateKey {
     ensure(callback)
     multihashing(this.bytes, 'sha2-256', callback)
   }
+
+  /**
+   * Gets the ID of the key.
+   *
+   * The key id is the base58 encoding of the SHA-256 multihash of its public key.
+   * The public key is a protobuf encoding containing a type and the DER encoding
+   * of the PKCS SubjectPublicKeyInfo.
+   *
+   * @param {function(Error, id)} callback
+   * @returns {undefined}
+   */
+  id (callback) {
+    this.public.hash((err, hash) => {
+      if (err) {
+        return callback(err)
+      }
+      callback(null, bs58.encode(hash))
+    })
+  }
+
+  /**
+   * Exports the key into a password protected PEM format
+   *
+   * @param {string} [format] - Defaults to 'pkcs-8'.
+   * @param {string} password - The password to read the encrypted PEM
+   * @param {function(Error, KeyInfo)} callback
+   * @returns {undefined}
+   */
+  export (format, password, callback) {
+    if (typeof password === 'function') {
+      callback = password
+      password = format
+      format = 'pkcs-8'
+    }
+
+    setImmediate(() => {
+      ensure(callback)
+
+      let err = null
+      let pem = null
+      try {
+        const key = KEYUTIL.getKey(this._key) // _key is a JWK (JSON Web Key)
+        if (format === 'pkcs-8') {
+          pem = KEYUTIL.getPEM(key, 'PKCS8PRV', password)
+        } else {
+          err = new Error(`Unknown export format '${format}'`)
+        }
+      } catch (e) {
+        err = e
+      }
+
+      callback(err, pem)
+    })
+  }
 }
 
 function unmarshalRsaPrivateKey (bytes, callback) {
@@ -108,6 +165,16 @@ function unmarshalRsaPublicKey (bytes) {
   return new RsaPublicKey(jwk)
 }
 
+function fromJwk (jwk, callback) {
+  crypto.unmarshalPrivateKey(jwk, (err, keys) => {
+    if (err) {
+      return callback(err)
+    }
+
+    callback(null, new RsaPrivateKey(keys.privateKey, keys.publicKey))
+  })
+}
+
 function generateKeyPair (bits, cb) {
   crypto.generateKey(bits, (err, keys) => {
     if (err) {
@@ -129,5 +196,6 @@ module.exports = {
   RsaPrivateKey,
   unmarshalRsaPublicKey,
   unmarshalRsaPrivateKey,
-  generateKeyPair
+  generateKeyPair,
+  fromJwk
 }