diff --git a/onionrblocks/__init__.py b/onionrblocks/__init__.py
index 1134b3d..9a2b534 100644
--- a/onionrblocks/__init__.py
+++ b/onionrblocks/__init__.py
@@ -1,8 +1,20 @@
 from typing import Union
 from time import time
+from binascii import hexlify
+
 import kasten
 
 
+from .types import AnonymousVDFBlockResult
+
+
+def __str_to_bytes(data: str):
+    try:
+        return data.encode('utf-8')
+    except AttributeError:
+        return data
+
+
 def _packer(block_data: bytes, **kasten_header) -> kasten.main.KastenPacked:
     def __get_optional(key, default):
         try:
@@ -16,7 +28,7 @@ def _packer(block_data: bytes, **kasten_header) -> kasten.main.KastenPacked:
         kasten_header['encrypt mode'],
         __get_optional('signer', b''),
         __get_optional('signature', b''),
-        __get_optional('metadata', {}),
+        __get_optional('metadata', None),
         int(time()//60 * 60)
         )
 
@@ -25,8 +37,16 @@ def _packer(block_data: bytes, **kasten_header) -> kasten.main.KastenPacked:
 # They do not handle sigs or encryption (at least never directly)
 
 def create_block_anonymous_vdf(
-        rounds: int, block_data: Union[str, bytes], **block_header):
+        rounds: int,
+        block_data: Union[str, bytes],
+        **block_header) -> AnonymousVDFBlockResult:
+    block_data = __str_to_bytes(block_data)
     # Block with anonymous VDF as proof
-    packed = _packer(block_data, **block_header)
-    return kasten.generator.KastenMimcGenerator.generate(
-        packed, rounds)
+
+    packed: kasten.types.KastenPacked = _packer(block_data, **block_header)
+    kasten_result: kasten.Kasten = \
+        kasten.generator.KastenMimcGenerator.generate(packed, rounds)
+    print('orig packed', packed)
+    return AnonymousVDFBlockResult(
+        kasten_result.id,
+        kasten_result.get_packed())
diff --git a/tests/test_vdf_block.py b/tests/test_vdf_block.py
index 3bf7195..ab7a93a 100644
--- a/tests/test_vdf_block.py
+++ b/tests/test_vdf_block.py
@@ -9,10 +9,13 @@ class TestVDFBlock(unittest.TestCase):
 
     def test_basic(self):
         rounds = 10**4
-        k = onionrblocks.create_block_anonymous_vdf(rounds, b'test', **{'type': 'test', 'encrypt mode': 0})
-        raw = k.data
-        id = binascii.hexlify(k.id)
-        kasten.generator.vdf_verify(raw, id, rounds)
+        data = b'test data'
+        k = onionrblocks.create_block_anonymous_vdf(rounds, data, **{'type': 'test', 'encrypt mode': 0})
+        raw = k.raw_bytes
+        id = int.from_bytes(k.hex_checksum, byteorder="big")
+        #print(id, raw)
+        print(raw)
+        kasten.generator.KastenMimcGenerator.validate_id(id, raw, rounds)
 
 
 unittest.main()
\ No newline at end of file