diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..3c3629e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+node_modules
diff --git a/README.md b/README.md
index 1c09ba4..587671a 100644
--- a/README.md
+++ b/README.md
@@ -167,6 +167,14 @@ Takes a `HandshakeState` and destroys all internal data (eg. securely zeros out
 data contained in Buffer-like objects and resets state). Use this to dispose of
 state objects after a split has occurred or upon error
 
+### `{publicKey, secretKey} = noise.keygen([obj])`
+
+Generate a new keypair with a `secretKey` and `publicKey`.  You can optionally pass in your own `obj` that contains pre-allocated buffers on the `obj.publicKey` and `obj.publicKey` properties.  Otherwise they are created for you.
+
+### `{publicKey, secretKey} = noise.seedKeygen(seed)`
+
+Pass in a `seed` buffer of length `sodium.crypto_kx_SEEDBYTES` and get back an object with coresponding `publicKey` and `secretKey`.
+
 ### Split
 
 If no more message patterns are left to process, a **Split** will occur, as
diff --git a/dh.js b/dh.js
index 5cd790c..6c55d6b 100644
--- a/dh.js
+++ b/dh.js
@@ -26,7 +26,7 @@ function generateKeypair (pk, sk) {
 function generateSeedKeypair (pk, sk, seed) {
   assert(pk.byteLength === PKLEN)
   assert(sk.byteLength === SKLEN)
-  assert(seed.byteLength === SKLEN)
+  assert(seed.byteLength === SEEDLEN)
 
   sodium.crypto_kx_seed_keypair(pk, sk, seed)
 }
diff --git a/handshake-state.js b/handshake-state.js
index 844c89f..385857b 100644
--- a/handshake-state.js
+++ b/handshake-state.js
@@ -482,18 +482,14 @@ function destroy (state) {
   state.messagePatterns = null
 }
 
-function keygen (obj, sk) {
+function keygen (obj) {
   if (!obj) {
     obj = {publicKey: sodium.sodium_malloc(PKLEN), secretKey: sodium.sodium_malloc(SKLEN)}
     return keygen(obj)
   }
 
-  if (obj.publicKey) {
-    dh.generateKeypair(obj.publicKey, obj.secretKey)
-    return obj
-  }
-
-  if (obj.byteLength != null) dh.generateKeypair(null, obj)
+  dh.generateKeypair(obj.publicKey, obj.secretKey)
+  return obj
 }
 
 function seedKeygen (seed) {