Create public key validation function

evm/utils/address.py

@@ -10,6 +10,10 @@
     private_key_to_public_key,
 )
 
+from evm.validation import (
+    validate_raw_public_key
+)
+
 
 def force_bytes_to_address(value):
     trimmed_value = value[-20:]
@@ -27,8 +31,5 @@ def private_key_to_address(private_key):
 
 
 def public_key_to_address(public_key):
-    if len(public_key) != 64:
-        raise ValueError(
-            "Unexpected public key format: {}. Public keys must be 64 bytes long and must not "
-            "include the fixed \x04 prefix".format(public_key))
+    validate_raw_public_key(public_key)
     return keccak(public_key)[-20:]

evm/utils/secp256k1.py

@@ -17,12 +17,13 @@
     pad32,
 )
 
+from evm.validation import (
+    validate_raw_public_key
+)
+
 
 def decode_public_key(public_key):
-    if len(public_key) != 64:
-        raise ValueError(
-            "Unexpected public key format: {}. Public keys must be 64 bytes long and must not "
-            "include the fixed \x04 prefix".format(public_key))
+    validate_raw_public_key(public_key)
     left = big_endian_to_int(public_key[0:32])
     right = big_endian_to_int(public_key[32:64])
     return left, right

evm/validation.py

@@ -159,3 +159,9 @@ def validate_vm_block_numbers(vm_block_numbers):
 
     for block_number in vm_block_numbers:
         validate_block_number(block_number)
+
+
+def validate_raw_public_key(value):
+    validate_is_bytes(value)
+    if len(value) != 64:
+        raise ValidationError("Unexpected public key format.  Must be length 64 byte")

tests/core/validation/test_validation.py

@@ -23,6 +23,7 @@
     validate_lt_secpk1n,
     validate_lt_secpk1n2,
     validate_multiple_of,
+    validate_raw_public_key,
     validate_stack_item,
     validate_uint256,
     validate_unique,
@@ -31,6 +32,9 @@
 )
 
 
+byte = b"\x00"
+
+
 @pytest.mark.parametrize(
     "value,is_valid",
     (
@@ -393,3 +397,19 @@ def test_validate_vm_block_numbers(vm_block_numbers, is_valid):
     else:
         with pytest.raises(ValidationError):
             validate_vm_block_numbers(vm_block_numbers)
+
+
+@pytest.mark.parametrize(
+    "public_key_value,is_valid",
+    (
+        (byte, False),
+        (("1" * 64), False),
+        (byte * 64, True),
+    ),
+)
+def test_validate_raw_public_key(public_key_value, is_valid):
+    if is_valid:
+        validate_raw_public_key(public_key_value)
+    else:
+        with pytest.raises(ValidationError):
+            validate_raw_public_key(public_key_value)