diff --git a/pom.xml b/pom.xml
index a6d53c3..e268f0d 100644
--- a/pom.xml
+++ b/pom.xml
@@ -36,8 +36,8 @@
 
         <dependency>
             <groupId>org.bouncycastle</groupId>
-            <artifactId>bcprov-jdk15on</artifactId>
-            <version>1.67</version>
+            <artifactId>bcprov-jdk18on</artifactId>
+            <version>1.86</version>
         </dependency>
 
         <dependency>
diff --git a/src/main/java/com/github/manevolent/ts3j/protocol/packet/transformation/PacketTransformation.java b/src/main/java/com/github/manevolent/ts3j/protocol/packet/transformation/PacketTransformation.java
index 0a6a3bb..c2a8a3f 100644
--- a/src/main/java/com/github/manevolent/ts3j/protocol/packet/transformation/PacketTransformation.java
+++ b/src/main/java/com/github/manevolent/ts3j/protocol/packet/transformation/PacketTransformation.java
@@ -24,7 +24,7 @@ public class PacketTransformation {
 
     public PacketTransformation(byte[] ivStruct, byte[] fakeMac) {
         this.ivStruct = ivStruct;
-        this.cipher = new EAXBlockCipher(new AESEngine());
+        this.cipher = new EAXBlockCipher(AESEngine.newInstance());
         this.fakeMac = fakeMac;
     }
 
@@ -86,20 +86,18 @@ public class PacketTransformation {
         int dataLen = packet.getBody().getSize();
         ByteBuffer packetBuffer = packet.writeBody(ByteBuffer.allocate(dataLen).order(ByteOrder.BIG_ENDIAN));
 
-        byte[] result;
-        int len;
+        // TS3 derives key and nonce from the packet id, so a resend encrypts under the same pair
+        // again. BouncyCastle refuses that on a cipher that has seen it, hence one per packet.
+        EAXBlockCipher cipher = new EAXBlockCipher(AESEngine.newInstance());
+        cipher.init(true, cipherParameters);
 
-        synchronized (cipher) {
-            cipher.init(true, cipherParameters);
+        byte[] result = new byte[cipher.getOutputSize(dataLen)];
+        int len = cipher.processBytes(packetBuffer.array(), 0, dataLen, result, 0);
 
-            result = new byte[cipher.getOutputSize(dataLen)];
-            len = cipher.processBytes(packetBuffer.array(), 0, dataLen, result, 0);
-
-            try {
-                len += cipher.doFinal(result, len);
-            } catch (InvalidCipherTextException e) {
-                throw new RuntimeException(e);
-            }
+        try {
+            len += cipher.doFinal(result, len);
+        } catch (InvalidCipherTextException e) {
+            throw new RuntimeException(e);
         }
 
         ByteBuffer outputBuffer = ByteBuffer.allocate(MAC_LEN + headerWithoutMac.length + (len - MAC_LEN));
diff --git a/src/test/java/com/github/manevolent/ts3j/EncryptionTest.java b/src/test/java/com/github/manevolent/ts3j/EncryptionTest.java
index 03461b2..e521337 100644
--- a/src/test/java/com/github/manevolent/ts3j/EncryptionTest.java
+++ b/src/test/java/com/github/manevolent/ts3j/EncryptionTest.java
@@ -53,6 +53,10 @@ public class EncryptionTest extends TestCase {
 
         byte[] packetBytes = transformation.encrypt(packet).array();
         transformation.decrypt(header, ByteBuffer.wrap(packetBytes), packet.getBody().getSize());
+
+        // A resend encrypts the same packet again, under the same key and nonce.
+        byte[] resent = transformation.encrypt(packet).array();
+        assertTrue(java.util.Arrays.equals(packetBytes, resent));
     }
 
 }