added arg checks, fixed typo in MLKEM test (checking wrong algorithm name)

Author: dghgit

prov/src/main/java/org/bouncycastle/jcajce/provider/asymmetric/mlkem/MLKEMCipherSpi.java

@@ -34,7 +34,7 @@
 import org.bouncycastle.util.Exceptions;
 
 class MLKEMCipherSpi
-        extends CipherSpi
+    extends CipherSpi
 {
     private final String algorithmName;
     private MLKEMGenerator kemGen;

prov/src/main/java/org/bouncycastle/jcajce/spec/KTSParameterSpec.java

@@ -88,6 +88,11 @@ public Builder withNoKdf()
          */
         public Builder withKdfAlgorithm(AlgorithmIdentifier kdfAlgorithm)
         {
+            if (kdfAlgorithm == null)
+            {
+                throw new NullPointerException("kdfAlgorithm cannot be null");
+            }
+
             this.kdfAlgorithm = kdfAlgorithm;
 
             return this;

prov/src/test/java/org/bouncycastle/pqc/jcajce/provider/test/MLKEMTest.java

@@ -124,7 +124,7 @@ private void performKEMScipher(KeyPair kp, String algorithm, KTSParameterSpec kt
         Cipher w1 = Cipher.getInstance(algorithm, "BC");
 
         byte[] keyBytes;
-        if (algorithm.endsWith("KWP"))
+        if (ktsParameterSpec.getKeyAlgorithmName().endsWith("KWP"))
         {
             keyBytes = Hex.decode("000102030405060708090a0b0c0d0e0faa");
         }