diff --git a/core/src/main/java/org/bouncycastle/crypto/hpke/DHKEM.java b/core/src/main/java/org/bouncycastle/crypto/hpke/DHKEM.java
index 84f40ba68a..cd9a7c8018 100644
--- a/core/src/main/java/org/bouncycastle/crypto/hpke/DHKEM.java
+++ b/core/src/main/java/org/bouncycastle/crypto/hpke/DHKEM.java
@@ -282,7 +282,7 @@ public AsymmetricCipherKeyPair DeserializePrivateKey(byte[] skEncoded, byte[] pk
         }
     }
 
-    int getEncryptionSize()
+    protected int getEncryptionSize()
     {
         return Nenc;
     }
diff --git a/core/src/main/java/org/bouncycastle/crypto/hpke/KEM.java b/core/src/main/java/org/bouncycastle/crypto/hpke/KEM.java
index 35bb58348f..54936c0423 100644
--- a/core/src/main/java/org/bouncycastle/crypto/hpke/KEM.java
+++ b/core/src/main/java/org/bouncycastle/crypto/hpke/KEM.java
@@ -10,26 +10,26 @@
 public abstract class KEM
 {
     // Key Generation
-    abstract AsymmetricCipherKeyPair GeneratePrivateKey();
-    abstract AsymmetricCipherKeyPair DeriveKeyPair(byte[] ikm);
+    protected abstract AsymmetricCipherKeyPair GeneratePrivateKey();
+    protected abstract AsymmetricCipherKeyPair DeriveKeyPair(byte[] ikm);
 
     // Encapsulates a shared secret for a given public key and returns the encapsulated key and shared secret.
-    abstract byte[][] Encap(AsymmetricKeyParameter recipientPublicKey);
-    abstract byte[][] Encap(AsymmetricKeyParameter pkR, AsymmetricCipherKeyPair kpE);
-    abstract byte[][] AuthEncap(AsymmetricKeyParameter pkR, AsymmetricCipherKeyPair kpS);
+    protected abstract byte[][] Encap(AsymmetricKeyParameter recipientPublicKey);
+    protected abstract byte[][] Encap(AsymmetricKeyParameter pkR, AsymmetricCipherKeyPair kpE);
+    protected abstract byte[][] AuthEncap(AsymmetricKeyParameter pkR, AsymmetricCipherKeyPair kpS);
 
     // Decapsulates the given encapsulated key using the recipient's key pair and returns the shared secret.
-    abstract byte[] Decap(byte[] encapsulatedKey, AsymmetricCipherKeyPair recipientKeyPair);
-    abstract byte[] AuthDecap(byte[] enc, AsymmetricCipherKeyPair kpR, AsymmetricKeyParameter pkS);
+    protected abstract byte[] Decap(byte[] encapsulatedKey, AsymmetricCipherKeyPair recipientKeyPair);
+    protected abstract byte[] AuthDecap(byte[] enc, AsymmetricCipherKeyPair kpR, AsymmetricKeyParameter pkS);
 
     // Serialization
-    abstract byte[] SerializePublicKey(AsymmetricKeyParameter publicKey);
-    abstract byte[] SerializePrivateKey(AsymmetricKeyParameter key);
+    protected abstract byte[] SerializePublicKey(AsymmetricKeyParameter publicKey);
+    protected abstract byte[] SerializePrivateKey(AsymmetricKeyParameter key);
 
     // Deserialization
-    abstract AsymmetricKeyParameter DeserializePublicKey(byte[] encodedPublicKey);
-    abstract AsymmetricCipherKeyPair DeserializePrivateKey(byte[] skEncoded, byte[] pkEncoded);
+    protected abstract AsymmetricKeyParameter DeserializePublicKey(byte[] encodedPublicKey);
+    protected abstract AsymmetricCipherKeyPair DeserializePrivateKey(byte[] skEncoded, byte[] pkEncoded);
 
-    abstract int getEncryptionSize();
+    protected abstract int getEncryptionSize();
 
-}
\ No newline at end of file
+}