diff --git a/src/chainstate/stacks/auth.rs b/src/chainstate/stacks/auth.rs
new file mode 100644
index 000000000..ccd9aa404
--- /dev/null
+++ b/src/chainstate/stacks/auth.rs
@@ -0,0 +1,64 @@
+/*
+ copyright: (c) 2013-2019 by Blockstack PBC, a public benefit corporation.
+
+ This file is part of Blockstack.
+
+ Blockstack is free software. You may redistribute or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License or
+ (at your option) any later version.
+
+ Blockstack is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY, including without the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Blockstack. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+use net::StacksMessageCodec;
+use net::Error as net_error;
+use net::codec::{read_next, write_next};
+
+use chainstate::stacks::TransactionAuth;
+use chainstate::stacks::StacksPublicKey;
+use net::StacksPublicKeyBuffer;
+use net::MessageSignature;
+
+impl StacksMessageCodec for TransactionAuth {
+    fn serialize(&self) -> Vec<u8> {
+        let mut res = vec![];
+        let public_key_buffers : Vec<StacksPublicKeyBuffer> = self.public_keys
+            .iter()
+            .map(|pubk| StacksPublicKeyBuffer::from_public_key(&pubk))
+            .collect();
+
+        write_next(&mut res, &self.nonce);
+        write_next(&mut res, &public_key_buffers);
+        write_next(&mut res, &self.signatures);
+        write_next(&mut res, &self.signatures_required);
+        res
+    }
+
+    fn deserialize(buf: &Vec<u8>, index: &mut u32, max_size: u32) -> Result<TransactionAuth, net_error> {
+        let nonce : u64                                     = read_next(buf, index, max_size)?;
+        let public_key_buffers: Vec<StacksPublicKeyBuffer>  = read_next(buf, index, max_size)?;
+        let signatures: Vec<MessageSignature>               = read_next(buf, index, max_size)?;
+        let signatures_required: u16                        = read_next(buf, index, max_size)?;
+
+        // attempt to parse all public keys
+        let mut public_keys = vec![];
+        for pubkey_buf in &public_key_buffers {
+            let pubk = pubkey_buf.to_public_key()?;
+            public_keys.push(pubk);
+        }
+
+        Ok(TransactionAuth {
+            nonce,
+            public_keys,
+            signatures,
+            signatures_required
+        })
+    }
+}