From 26c6ab9b9705f619e4449a36baf6300ce2f19f71 Mon Sep 17 00:00:00 2001
From: Ismael Bejarano <ismael.bejarano@coinfabrik.com>
Date: Fri, 12 Aug 2016 00:23:20 -0300
Subject: [PATCH] Parameters for the ECDH key derivation function

---
 src/index.js           |  6 +++++
 src/type/kdf_params.js | 61 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100644 src/type/kdf_params.js

diff --git a/src/index.js b/src/index.js
index e701837b..fd0e9de5 100644
--- a/src/index.js
+++ b/src/index.js
@@ -83,6 +83,12 @@ export { default as Keyid } from './type/keyid';
  */
 export { default as EcdhSymmetricKey } from './type/ecdh_symkey';
 
+/**
+ * @see module:type/kdf_params
+ * @name module:openpgp.KdfParams
+ */
+export { default as KdfParams } from './type/kdf_params';
+
 /**
  * @see module:type/oid
  * @name module:openpgp.Oid
diff --git a/src/type/kdf_params.js b/src/type/kdf_params.js
new file mode 100644
index 00000000..1a6d1371
--- /dev/null
+++ b/src/type/kdf_params.js
@@ -0,0 +1,61 @@
+// OpenPGP.js - An OpenPGP implementation in javascript
+// Copyright (C) 2015-2016 Decentral
+//
+// This library is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3.0 of the License, or (at your option) any later version.
+//
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public
+// License along with this library; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+
+/**
+ * Implementation of type KDF parameters RFC 6637<br/>
+ * <br/>
+ * @requires enums
+ * @module type/kdf_params
+ */
+
+'use strict';
+
+import enums from '../enums.js';
+
+module.exports = KdfParams;
+
+/**
+ * @constructor
+ * @param  {enums.hash}       hash    Hash algorithm
+ * @param  {enums.symmetric}  cipher  Symmetric algorithm
+ */
+function KdfParams(hash, cipher) {
+  this.hash = hash || enums.hash.sha1;
+  this.cipher = cipher || enums.symmetric.aes128;
+}
+
+/**
+ * Read KdfParams from an Uint8Array
+ * @param  {Uint8Array}  input  Where to read the KdfParams from
+ * @return {Number}             Number of read bytes
+ */
+KdfParams.prototype.read = function (input) {
+  if (input.length < 4 || input[0] !== 3 || input[1] !== 1) {
+    throw new Error('Cannot read KdfParams');
+  }
+  this.hash = input[2];
+  this.cipher = input[3];
+  return 4;
+};
+
+/**
+ * Write KdfParams to an Uint8Array
+ * @return  {Uint8Array}  Array with the KdfParams value
+ */
+KdfParams.prototype.write = function () {
+  return new Uint8Array([3, 1, this.hash, this.cipher]);
+};