diff --git a/core/src/core/block.rs b/core/src/core/block.rs
index 002d9cd327..a6b5f9f318 100644
--- a/core/src/core/block.rs
+++ b/core/src/core/block.rs
@@ -25,7 +25,6 @@ use core::{Input, Output, Proof, TxProof, Transaction};
 use core::transaction::merkle_inputs_outputs;
 use core::{PROOFSIZE, REWARD};
 use core::hash::{Hash, Hashed, ZERO_HASH};
-use core::ser::MAX_IN_OUT_LEN;
 use ser::{self, Readable, Reader, Writeable, Writer, ser_vec};
 
 /// Block header, fairly standard compared to other blockchains.
@@ -140,7 +139,7 @@ impl Readable<Block> for Block {
 		let input_len = try!(reader.read_u64());
 		let output_len = try!(reader.read_u64());
 		let proof_len = try!(reader.read_u64());
-		if input_len > MAX_IN_OUT_LEN || output_len > MAX_IN_OUT_LEN || proof_len > MAX_IN_OUT_LEN {
+		if input_len > ser::MAX_IN_OUT_LEN || output_len > ser::MAX_IN_OUT_LEN || proof_len > ser::MAX_IN_OUT_LEN {
 			return Err(ser::Error::TooLargeReadErr("Too many inputs, outputs or proofs.".to_string()));
 		}
 
diff --git a/core/src/core/mod.rs b/core/src/core/mod.rs
index 6be1e7c1d6..cffccadb2b 100644
--- a/core/src/core/mod.rs
+++ b/core/src/core/mod.rs
@@ -19,7 +19,6 @@ pub mod hash;
 pub mod transaction;
 #[allow(dead_code)]
 #[macro_use]
-mod ser;
 
 pub use self::block::{Block, BlockHeader};
 pub use self::transaction::{Transaction, Input, Output, TxProof};
diff --git a/core/src/core/ser.rs b/core/src/core/ser.rs
deleted file mode 100644
index 49a6fae8a0..0000000000
--- a/core/src/core/ser.rs
+++ /dev/null
@@ -1,57 +0,0 @@
-// Copyright 2016 The Grin Developers
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-//! Binary stream serialization and deserialzation for core types from trusted
-//! Write or Read implementations. Issues like starvation or too big sends are
-//! expected to be handled upstream.
-
-use time;
-
-use std::io::{Write, Read};
-use core::{self, hash};
-use ser::*;
-
-use secp::Signature;
-use secp::key::SecretKey;
-use secp::pedersen::{Commitment, RangeProof};
-
-pub const MAX_IN_OUT_LEN: u64 = 50000;
-
-macro_rules! impl_slice_bytes {
-  ($byteable: ty) => {
-    impl AsFixedBytes for $byteable {
-      fn as_fixed_bytes(&self) -> &[u8] {
-        &self[..]
-      }
-    }
-  }
-}
-
-impl_slice_bytes!(SecretKey);
-impl_slice_bytes!(Signature);
-impl_slice_bytes!(Commitment);
-impl_slice_bytes!(Vec<u8>);
-
-impl AsFixedBytes for hash::Hash {
-	fn as_fixed_bytes(&self) -> &[u8] {
-		self.to_slice()
-	}
-}
-
-impl AsFixedBytes for RangeProof {
-	fn as_fixed_bytes(&self) -> &[u8] {
-		&self.bytes()
-	}
-}
-
diff --git a/core/src/core/transaction.rs b/core/src/core/transaction.rs
index 2c615b48a9..777d55741c 100644
--- a/core/src/core/transaction.rs
+++ b/core/src/core/transaction.rs
@@ -17,7 +17,6 @@
 use core::Committed;
 use core::MerkleRow;
 use core::hash::{Hashed, Hash};
-use core::ser::MAX_IN_OUT_LEN;
 use ser::{self, Reader, Writer, Readable, Writeable};
 
 use secp::{self, Secp256k1, Message, Signature};
@@ -91,7 +90,7 @@ impl Readable<Transaction> for Transaction {
 		let output_len = try!(reader.read_u64());
 
 		// in case a facetious miner sends us more than what we can allocate
-		if input_len > MAX_IN_OUT_LEN || output_len > MAX_IN_OUT_LEN {
+		if input_len > ser::MAX_IN_OUT_LEN || output_len > ser::MAX_IN_OUT_LEN {
 			return Err(ser::Error::TooLargeReadErr("Too many inputs or outputs.".to_string()));
 		}
 
diff --git a/core/src/ser.rs b/core/src/ser.rs
index a0c9a607a9..2671652192 100644
--- a/core/src/ser.rs
+++ b/core/src/ser.rs
@@ -23,6 +23,9 @@ use std::io;
 use std::io::{Write, Read};
 use byteorder::{ReadBytesExt, WriteBytesExt, BigEndian};
 
+/// Maximum number of inputs or outputs in a transaction
+pub const MAX_IN_OUT_LEN: u64 = 50000;
+
 /// Possible errors deriving from serializing or deserializing.
 #[derive(Debug)]
 pub enum Error {
@@ -170,3 +173,31 @@ impl<'a> Writer for BinWriter<'a> {
 		self.sink.write_all(bs).err().map(Error::IOErr)
 	}
 }
+
+macro_rules! impl_slice_bytes {
+  ($byteable: ty) => {
+    impl AsFixedBytes for $byteable {
+      fn as_fixed_bytes(&self) -> &[u8] {
+        &self[..]
+      }
+    }
+  }
+}
+
+impl_slice_bytes!(::secp::key::SecretKey);
+impl_slice_bytes!(::secp::Signature);
+impl_slice_bytes!(::secp::pedersen::Commitment);
+impl_slice_bytes!(Vec<u8>);
+
+impl AsFixedBytes for ::core::hash::Hash {
+	fn as_fixed_bytes(&self) -> &[u8] {
+		self.to_slice()
+	}
+}
+
+impl AsFixedBytes for ::secp::pedersen::RangeProof {
+	fn as_fixed_bytes(&self) -> &[u8] {
+		&self.bytes()
+	}
+}
+