diff --git a/src/fernet.js b/src/fernet.js
index 0932ee2..3e5a884 100644
--- a/src/fernet.js
+++ b/src/fernet.js
@@ -10,12 +10,19 @@ class Fernet {
             throw new Error("Token key cannot be null");
         }
 
-        if (key.length !== 32) {
-            throw new Error(`Token key must be 32 bytes, not ${key.length}`);
+        if (key.length === 32) {
+            // AES-128-CBC mode
+            this.mode = 'aes-128-cbc';
+            this._signing_key = key.slice(0, 16);
+            this._encryption_key = key.slice(16);
+        } else if (key.length === 64) {
+            // AES-256-CBC mode (matches Python's Link.MODE_AES256_CBC)
+            this.mode = 'aes-256-cbc';
+            this._signing_key = key.slice(0, 32);
+            this._encryption_key = key.slice(32);
+        } else {
+            throw new Error(`Token key must be 32 or 64 bytes, not ${key.length}`);
         }
-
-        this._signing_key = key.slice(0, 16);
-        this._encryption_key = key.slice(16);
     }
 
     static generateKey() {
@@ -46,7 +53,7 @@ class Fernet {
         const iv = crypto.randomBytes(16);
         const paddedData = PKCS7.pad(data);
 
-        const cipher = crypto.createCipheriv('aes-128-cbc', this._encryption_key, iv);
+        const cipher = crypto.createCipheriv(this.mode, this._encryption_key, iv);
         cipher.setAutoPadding(false); // disable automatic pkcs7 padding by crypto lib
         let ciphertext = cipher.update(paddedData);
         ciphertext = Buffer.concat([ciphertext, cipher.final()]);
@@ -73,7 +80,7 @@ class Fernet {
         const iv = token.slice(0, 16);
         const ciphertext = token.slice(16, -32);
 
-        const decipher = crypto.createDecipheriv('aes-128-cbc', this._encryption_key, iv);
+        const decipher = crypto.createDecipheriv(this.mode, this._encryption_key, iv);
         decipher.setAutoPadding(false); // disable automatic pkcs7 padding by crypto lib
         let plaintext = decipher.update(ciphertext);
         plaintext = Buffer.concat([plaintext, decipher.final()]);
diff --git a/src/interfaces/interface.js b/src/interfaces/interface.js
index 68c72d9..972ef5e 100644
--- a/src/interfaces/interface.js
+++ b/src/interfaces/interface.js
@@ -6,6 +6,12 @@ class Interface {
         this.rns = null;
         this.name = name;
         this.hash = this.getHash();
+
+        // Interface statistics (match Python implementation)
+        this.rxb = 0;      // Received bytes counter
+        this.txb = 0;      // Transmitted bytes counter
+        this.online = false;  // Interface connection status
+        this.OUT = false;     // Whether interface can send data
     }
 
     setReticulumInstance(rns) {
diff --git a/src/interfaces/websocket_client_interface.js b/src/interfaces/websocket_client_interface.js
index 78500a4..33198ac 100644
--- a/src/interfaces/websocket_client_interface.js
+++ b/src/interfaces/websocket_client_interface.js
@@ -25,6 +25,8 @@ class WebsocketClientInterface extends Interface {
         // connect to server
         this.websocket.addEventListener("open", () => {
             console.log(`Connected to: ${this.name} [${this.url}]`);
+            this.online = true;
+            this.OUT = true;
         });
 
         // handle received data
@@ -56,6 +58,8 @@ class WebsocketClientInterface extends Interface {
         // connect to server
         this.websocket.on("open", () => {
             console.log(`Connected to: ${this.name} [${this.url}]`);
+            this.online = true;
+            this.OUT = true;
         });
 
         // handle received data
@@ -82,6 +86,8 @@ class WebsocketClientInterface extends Interface {
     onSocketClose() {
 
         console.error('Connection Closed');
+        this.online = false;
+        this.OUT = false;
 
         // auto reconnect
         setTimeout(() => {
@@ -91,7 +97,15 @@ class WebsocketClientInterface extends Interface {
     }
 
     sendData(data) {
+        // Check if WebSocket is ready (state 1 = OPEN)
+        if (!this.websocket || this.websocket.readyState !== 1) {
+            return;
+        }
+
         this.websocket.send(data);
+
+        // Increment TX byte counter (match Python implementation)
+        this.txb += data.length;
     }
 
     onDataReceived(data) {
@@ -106,6 +120,9 @@ class WebsocketClientInterface extends Interface {
             return;
         }
 
+        // Increment RX byte counter (match Python implementation)
+        this.rxb += data.length;
+
         // parse packet from bytes
         const packet = Packet.fromBytes(data);
 
diff --git a/src/link.js b/src/link.js
index 5a84270..edf275b 100644
--- a/src/link.js
+++ b/src/link.js
@@ -285,8 +285,8 @@ class Link extends EventEmitter {
         // compute shared key
         this.sharedKey = Buffer.from(x25519.getSharedSecret(this.privateKeyBytes, this.peerPublicKeyBytes));
 
-        // create derived key
-        this.derivedKey = Cryptography.hkdf(32, this.sharedKey, this.hash);
+        // create derived key (64 bytes for AES256 mode to match Python's Link.MODE_AES256_CBC)
+        this.derivedKey = Cryptography.hkdf(64, this.sharedKey, this.hash);
 
     }
 
@@ -335,8 +335,15 @@ class Link extends EventEmitter {
     }
 
     decrypt(data) {
-        const fernet = new Fernet(this.derivedKey);
-        return fernet.decrypt(data);
+        try {
+            if (!this.derivedKey) {
+                return null;
+            }
+            const fernet = new Fernet(this.derivedKey);
+            return fernet.decrypt(data);
+        } catch (e) {
+            return null;
+        }
     }
 
     sign(data) {
@@ -386,6 +393,11 @@ class Link extends EventEmitter {
             // decrypt packet data
             const plaintext = this.decrypt(packet.data);
 
+            // check if decryption failed
+            if (!plaintext) {
+                return;
+            }
+
             // fire event
             this.emit("packet", {
                 packet: packet,
@@ -406,7 +418,7 @@ class Link extends EventEmitter {
 
             // decrypt link id from packet data and do nothing if it doesn't match this link
             const linkIdToClose = this.decrypt(packet.data);
-            if(!this.hash.equals(linkIdToClose)){
+            if(!linkIdToClose || !this.hash.equals(linkIdToClose)){
                 return;
             }