diff --git a/src/@types/handshake.ts b/src/@types/handshake.ts
new file mode 100644
index 0000000..265f769
--- /dev/null
+++ b/src/@types/handshake.ts
@@ -0,0 +1,39 @@
+import {bytes, bytes32, uint32, uint64} from "./basic";
+import {KeyPair} from "./libp2p";
+
+export type Hkdf = [bytes, bytes, bytes];
+
+export interface MessageBuffer {
+  ne: bytes32;
+  ns: bytes;
+  ciphertext: bytes;
+}
+
+export type CipherState = {
+  k: bytes32;
+  n: uint32;
+}
+
+export type SymmetricState = {
+  cs: CipherState;
+  ck: bytes32;  // chaining key
+  h: bytes32; // handshake hash
+}
+
+export type HandshakeState = {
+  ss: SymmetricState;
+  s: KeyPair;
+  e?: KeyPair;
+  rs: bytes32;
+  re: bytes32;
+  psk: bytes32;
+}
+
+export type NoiseSession = {
+  hs: HandshakeState;
+  h?: bytes32;
+  cs1?: CipherState;
+  cs2?: CipherState;
+  mc: uint64;
+  i: boolean;
+}
diff --git a/src/encoder.ts b/src/encoder.ts
index 383187b..8837d4f 100644
--- a/src/encoder.ts
+++ b/src/encoder.ts
@@ -1,6 +1,6 @@
 import {Buffer} from "buffer";
 import {bytes} from "./@types/basic";
-import {MessageBuffer} from "./handshakes/xx";
+import {MessageBuffer} from "./@types/handshake";
 
 export const int16BEEncode = (value, target, offset) => {
   target = target || Buffer.allocUnsafe(2);
diff --git a/src/handshake.ts b/src/handshake.ts
index d530e05..b2d96dc 100644
--- a/src/handshake.ts
+++ b/src/handshake.ts
@@ -1,8 +1,9 @@
 import { Buffer } from "buffer";
 
-import { bytes, bytes32 } from "./@types/basic";
-import { NoiseSession, XXHandshake } from "./handshakes/xx";
+import { XXHandshake } from "./handshakes/xx";
 import { KeyPair, PeerId } from "./@types/libp2p";
+import { bytes, bytes32 } from "./@types/basic";
+import { NoiseSession } from "./@types/handshake";
 import {
   createHandshakePayload,
   getHandshakePayload,
diff --git a/src/handshakes/xx.ts b/src/handshakes/xx.ts
index 7e0c9de..63f0dad 100644
--- a/src/handshakes/xx.ts
+++ b/src/handshakes/xx.ts
@@ -5,42 +5,8 @@ import { BN } from 'bn.js';
 import { bytes32, uint32, uint64, bytes } from '../@types/basic'
 import { KeyPair } from '../@types/libp2p'
 import { generateKeypair } from '../utils';
+import { CipherState, HandshakeState, Hkdf, MessageBuffer, NoiseSession, SymmetricState } from "../@types/handshake";
 
-export interface MessageBuffer {
-  ne: bytes32;
-  ns: bytes;
-  ciphertext: bytes;
-}
-
-type CipherState = {
-  k: bytes32;
-  n: uint32;
-}
-
-type SymmetricState = {
-  cs: CipherState;
-  ck: bytes32;  // chaining key
-  h: bytes32; // handshake hash
-}
-
-type HandshakeState = {
-  ss: SymmetricState;
-  s: KeyPair;
-  e?: KeyPair;
-  rs: bytes32;
-  re: bytes32;
-  psk: bytes32;
-}
-
-export type NoiseSession = {
-  hs: HandshakeState;
-  h?: bytes32;
-  cs1?: CipherState;
-  cs2?: CipherState;
-  mc: uint64;
-  i: boolean;
-}
-export type Hkdf = [bytes, bytes, bytes];
 
 const minNonce = 0;