Implement key_pair, sign, and verify

test/test_crypto.py

@@ -0,0 +1,9 @@
+"""Cryptography primitives test module."""
+
+from hypercore_crypto import key_pair
+
+
+def test_key_pair_length():
+    public_key, secret_key = key_pair()
+    assert len(public_key) == 32
+    assert len(secret_key) == 64