From f969d1f707ad6a9cc2e142d95f2cd94adbb1563d Mon Sep 17 00:00:00 2001
From: Christophe Diederichs <chris.d.itunes@gmail.com>
Date: Tue, 16 Jun 2020 15:54:44 +0200
Subject: [PATCH] correction: crypto_kx is not actually an alias of crypto_box

---
 crypto_kx.js | 33 ++++++++++++++++++++++++++++++---
 index.js     |  1 +
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/crypto_kx.js b/crypto_kx.js
index 04fb0bb..e77c6fb 100644
--- a/crypto_kx.js
+++ b/crypto_kx.js
@@ -1,9 +1,36 @@
-const { crypto_box_keypair, crypto_box_seed_keypair } = require('./crypto_box')
+const { crypto_scalarmult_base } = require('./crypto_scalarmult')
+const { crypto_generichash } = require('./crypto_generichash')
+const { randombytes_buf } = require('./randombytes')
+
+var crypto_kx_SEEDBYTES = 32
+var crypto_kx_PUBLICKEYBYTES = 32
+var crypto_kx_SECRETKEYBYTES = 32
 
 function crypto_kx_keypair (pk, sk) {
-  return crypto_box_keypair(pk, sk)
+  check(pk, crypto_kx_PUBLICKEYBYTES)
+  check(sk, crypto_kx_SECRETKEYBYTES)
+
+  randombytes_buf(sk, crypto_kx_SECRETKEYBYTES)
+  return crypto_scalarmult_base(pk, sk)
 }
 
 function crypto_kx_seed_keypair (pk, sk, seed) {
-  return crypto_box_seed_keypair(pk, sk, seed)
+  check(pk, crypto_kx_PUBLICKEYBYTES)
+  check(sk, crypto_kx_SECRETKEYBYTES)
+  check(seed, crypto_kx_SEEDBYTES)
+
+  crypto_generichash(sk, seed)
+  return crypto_scalarmult_base(pk, sk)
+}
+
+function check (buf, len) {
+  if (!buf || (len && buf.length < len)) throw new Error('Argument must be a buffer' + (len ? ' of length ' + len : ''))
+}
+
+module.exports = {
+  crypto_kx_keypair,
+  crypto_kx_seed_keypair,
+  crypto_kx_SEEDBYTES,
+  crypto_kx_SECRETKEYBYTES,
+  crypto_kx_PUBLICKEYBYTES
 }
diff --git a/index.js b/index.js
index 7c4e616..86a2184 100644
--- a/index.js
+++ b/index.js
@@ -29,6 +29,7 @@ forward(require('./crypto_box'))
 forward(require('./crypto_generichash'))
 forward(require('./crypto_hash'))
 forward(require('./crypto_kdf'))
+forward(require('./crypto_kx'))
 forward(require('./crypto_onetimeauth'))
 forward(require('./crypto_scalarmult'))
 forward(require('./crypto_secretbox'))