From f5123832bf4d1c80eb4983b573e7d8df38b4eaca Mon Sep 17 00:00:00 2001
From: diminator <dimi.dejonghe@gmail.com>
Date: Mon, 3 Apr 2017 21:35:19 +0200
Subject: [PATCH] seed from hash of secret

---
 dist/node/index.js    |  8 ++++----
 src/Ed25519Keypair.js | 16 ++++++++++++++--
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/dist/node/index.js b/dist/node/index.js
index 585c7b8..0802e13 100644
--- a/dist/node/index.js
+++ b/dist/node/index.js
@@ -3,11 +3,11 @@
 Object.defineProperty(exports, "__esModule", {
   value: true
 });
-exports.Connection = exports.Transaction = exports.Ed25519KeyPair = undefined;
+exports.Connection = exports.Transaction = exports.Ed25519Keypair = undefined;
 
-var _Ed25519Keypair = require('./Ed25519Keypair');
+var _Ed25519Keypair2 = require('./Ed25519Keypair');
 
-var _Ed25519Keypair2 = _interopRequireDefault(_Ed25519Keypair);
+var _Ed25519Keypair3 = _interopRequireDefault(_Ed25519Keypair2);
 
 var _transaction = require('./transaction');
 
@@ -21,6 +21,6 @@ function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj;
 
 function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
 
-exports.Ed25519KeyPair = _Ed25519Keypair2.default;
+exports.Ed25519Keypair = _Ed25519Keypair3.default;
 exports.Transaction = _Transaction;
 exports.Connection = _Connection;
\ No newline at end of file
diff --git a/src/Ed25519Keypair.js b/src/Ed25519Keypair.js
index 7781f6a..0bbe407 100644
--- a/src/Ed25519Keypair.js
+++ b/src/Ed25519Keypair.js
@@ -1,14 +1,26 @@
 import base58 from 'bs58';
 import nacl from 'tweetnacl';
+import sha3 from 'js-sha3';
 
 /**
  * @class Keypair Ed25519 keypair in base58 (as BigchainDB expects base58 keys)
  * @type {Object}
+ * @param {number} secret A seed that will be used as a key derivation function
  * @property {string} publicKey
  * @property {string} privateKey
  */
-export default function Ed25519Keypair() {
-    const keyPair = nacl.sign.keyPair();
+export default function Ed25519Keypair(secret) {
+    let keyPair;
+    if (secret) {
+        // Quick and dirty: use key derivation function instead
+        const secretHash = sha3.sha3_256
+            .create()
+            .update(secret)
+            .array();
+        keyPair = nacl.sign.keyPair.fromSeed(new Uint8Array(secretHash))
+    } else {
+        keyPair = nacl.sign.keyPair();
+    }
     this.publicKey = base58.encode(keyPair.publicKey);
     // tweetnacl's generated secret key is the secret key + public key (resulting in a 64-byte buffer)
     this.privateKey = base58.encode(keyPair.secretKey.slice(0, 32));