diff --git a/src/ssm.js b/src/ssm.js
index 3f94821..88ca5e5 100644
--- a/src/ssm.js
+++ b/src/ssm.js
@@ -1,5 +1,7 @@
 import sha256 from "./sha256.js";
 
+const HANDSHAKE_RESPONSE = 6;
+const CHALLENGE_RESPONSE = 9;
 const ACK_TYPE = 3;
 const INPUT_TYPE = 1;
 //const OUTPUT_TYPE = 0;
@@ -224,10 +226,10 @@ function uuidv4() {
 var ssm = {
   decode: function (buffer) {
     /*
-		var buf = new Uint8Array([
-			0x00,0x00,0x00,0x74,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x69,0x6e,0x70,0x75,0x74,0x5f,0x73,0x74,0x72,0x65,0x61,0x6d,0x5f,0x64,0x61,0x74,0x61,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x00,0x1e,0x5b,0x37,0xe2,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x73,0x0f,0x66,0x49,0x14,0x53,0x4e,0x2a,0x9f,0x01,0xa3,0x7d,0xbf,0xfe,0xfc,0xe1,0x65,0x34,0x34,0x33,0x36,0x35,0x62,0x39,0x35,0x31,0x31,0x36,0x32,0x65,0x64,0x61,0x36,0x34,0x61,0x63,0x65,0x66,0x64,0x32,0x37,0x35,0x37,0x32,0x32,0x30,0x39,0x65,0x00,0x00,0x00,0x03,0x00,0x00,0x00,0x16,0x7b,0x22,0x63,0x6f,0x6c,0x73,0x22,0x3a,0x32,0x30,0x32,0x2c,0x22,0x72,0x6f,0x77,0x73,0x22,0x3a,0x31,0x38,0x7d]);
-		console.log(buf);
-		*/
+    var buf = new Uint8Array([
+      0x00,0x00,0x00,0x74,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x69,0x6e,0x70,0x75,0x74,0x5f,0x73,0x74,0x72,0x65,0x61,0x6d,0x5f,0x64,0x61,0x74,0x61,0x00,0x00,0x00,0x01,0x00,0x00,0x00,0x00,0x1e,0x5b,0x37,0xe2,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x73,0x0f,0x66,0x49,0x14,0x53,0x4e,0x2a,0x9f,0x01,0xa3,0x7d,0xbf,0xfe,0xfc,0xe1,0x65,0x34,0x34,0x33,0x36,0x35,0x62,0x39,0x35,0x31,0x31,0x36,0x32,0x65,0x64,0x61,0x36,0x34,0x61,0x63,0x65,0x66,0x64,0x32,0x37,0x35,0x37,0x32,0x32,0x30,0x39,0x65,0x00,0x00,0x00,0x03,0x00,0x00,0x00,0x16,0x7b,0x22,0x63,0x6f,0x6c,0x73,0x22,0x3a,0x32,0x30,0x32,0x2c,0x22,0x72,0x6f,0x77,0x73,0x22,0x3a,0x31,0x38,0x7d]);
+    console.log(buf);
+    */
     var buf = new Uint8Array(buffer);
     var agentMessage = {
       headerLength: getInt(buf.slice(0, 4)), //4
@@ -259,6 +261,18 @@ var ssm = {
   sendInitMessage: function (connection, termOptions) {
     connection.send(ssm.buildInitMessage(termOptions));
   },
+
+  sendHandshakeResponse: function (connection, reqClientActions, kmsCipherText) {
+    const handshakeResp = ssm.buildHandshakeResponse(reqClientActions, kmsCipherText)
+    connection.send(handshakeResp);
+  },
+
+  sendChallengeResponse: function (connection, challengePayload) {
+    console.log(challengePayload)
+    const challengeResponse = ssm.buildChallengeResponse(challengePayload)
+    connection.send(challengeResponse);
+  },
+
   buildTokenMessage: function (token) {
     return JSON.stringify({
       MessageSchemaVersion: "1.0",
@@ -267,6 +281,54 @@ var ssm = {
     });
   },
 
+  buildHandshakeResponse: function (reqClientActions, kmsCipherText) {
+    let handshakePayload = {
+      ClientVersion: "1.2.312.0", // latest when this was written
+      ProcessedClientActions: [],
+      Errors: [],
+    }
+    for (let action of reqClientActions) {
+      let processedAction = {
+        ActionType: action.ActionType,
+      }
+      if (action.ActionType == "KMSEncryption") {
+        if (kmsCipherText) {
+          processedAction.ActionStatus = 1
+          processedAction.ActionResult = {
+            KMSCipherTextKey: Array.from(kmsCipherText),
+          }
+        }
+        else processedAction.ActionStatus = 2
+      }
+      else if (action.ActionType == "SessionType") {
+        processedAction.ActionStatus = 1
+      }
+      else processedAction.ActionStatus = 3
+      handshakePayload.ProcessedClientActions.push(processedAction)
+    }
+    messageSequenceNumber++;
+    var handshakeResp = buildAgentMessage(
+      JSON.stringify(handshakePayload),
+      "input_stream_data",
+      messageSequenceNumber,
+      HANDSHAKE_RESPONSE,
+      1
+    );
+    return agentMessageToBuffer(handshakeResp);
+  },
+
+  buildChallengeResponse: function (challengePayload) {
+    messageSequenceNumber++;
+    var challengeResp = buildAgentMessage(
+      challengePayload,
+      "input_stream_data",
+      messageSequenceNumber,
+      CHALLENGE_RESPONSE,
+      1
+    );
+    return agentMessageToBuffer(challengeResp);
+  },
+
   buildInitMessage: function (options) {
     var payload = {
       cols: options.cols,