diff --git a/TLS-Core/src/main/java/de/rub/nds/tlsattacker/core/protocol/preparator/RSAClientKeyExchangePreparator.java b/TLS-Core/src/main/java/de/rub/nds/tlsattacker/core/protocol/preparator/RSAClientKeyExchangePreparator.java
index 7b553625d..287130fdb 100644
--- a/TLS-Core/src/main/java/de/rub/nds/tlsattacker/core/protocol/preparator/RSAClientKeyExchangePreparator.java
+++ b/TLS-Core/src/main/java/de/rub/nds/tlsattacker/core/protocol/preparator/RSAClientKeyExchangePreparator.java
@@ -144,7 +144,7 @@ protected void prepareSerializedPublicKeyLength(T msg) {
     public byte[] decryptPremasterSecret() {
         BigInteger bigIntegerEncryptedPremasterSecret =
                 new BigInteger(1, msg.getPublicKey().getValue());
-        BigInteger serverPrivateKey = chooser.getServerX509Chooser().getConfig().getRsaPrivateKey();
+        BigInteger serverPrivateKey = chooser.getServerX509Chooser().getSubjectRsaPrivateKey();
         if (chooser.getServerX509Chooser().getSubjectRsaModulus().equals(BigInteger.ZERO)) {
             LOGGER.warn("RSA modulus is zero, returning new byte[0] as decryptedPremasterSecret");
             return new byte[0];