Don't store SecureRandom in MLKEMEngine

Author: peterdettman

core/src/main/java/org/bouncycastle/pqc/crypto/mlkem/MLKEMEngine.java

@@ -6,8 +6,6 @@
 
 class MLKEMEngine
 {
-    private SecureRandom random;
-
     private final MLKEMIndCpa indCpa;
 
     // constant parameters
@@ -183,17 +181,12 @@ public MLKEMEngine(int k)
         this.indCpa = new MLKEMIndCpa(this);
     }
 
-    public void init(SecureRandom random)
-    {
-        this.random = random;
-    }
-
     boolean checkModulus(byte[] t)
     {
         return PolyVec.checkModulus(this, t) < 0;
     }
 
-    public byte[][] generateKemKeyPair()
+    public byte[][] generateKemKeyPair(SecureRandom random)
     {
         byte[] d = new byte[KyberSymBytes];
         byte[] z = new byte[KyberSymBytes];

core/src/main/java/org/bouncycastle/pqc/crypto/mlkem/MLKEMGenerator.java

@@ -30,7 +30,6 @@ public SecretWithEncapsulation internalGenerateEncapsulated(AsymmetricKeyParamet
     {
         MLKEMPublicKeyParameters key = (MLKEMPublicKeyParameters)recipientKey;
         MLKEMEngine engine = key.getParameters().getEngine();
-        engine.init(sr);
 
         byte[][] kemEncrypt = engine.kemEncrypt(key, randBytes);
         return new SecretWithEncapsulationImpl(kemEncrypt[0], kemEncrypt[1]);

core/src/main/java/org/bouncycastle/pqc/crypto/mlkem/MLKEMKeyPairGenerator.java

@@ -25,9 +25,7 @@ private AsymmetricCipherKeyPair genKeyPair()
     {
         MLKEMEngine engine = mlkemParams.getEngine();
 
-        engine.init(random);
-
-        byte[][] keyPair = engine.generateKemKeyPair();
+        byte[][] keyPair = engine.generateKemKeyPair(random);
 
         MLKEMPublicKeyParameters pubKey = new MLKEMPublicKeyParameters(mlkemParams, keyPair[0], keyPair[1]);
         MLKEMPrivateKeyParameters privKey = new MLKEMPrivateKeyParameters(mlkemParams,  keyPair[2], keyPair[3], keyPair[4], keyPair[0], keyPair[1], keyPair[5]);