1 files changed, 66 insertions, 0 deletions
diff --git a/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/elgamal/ElGamalUtil.java b/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/elgamal/ElGamalUtil.java
new file mode 100644
index 00000000..65c7c412
--- /dev/null
+++ b/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/elgamal/ElGamalUtil.java
@@ -0,0 +1,66 @@
+package org.spongycastle.jcajce.provider.asymmetric.elgamal;
+
+import java.security.InvalidKeyException;
+import java.security.PrivateKey;
+import java.security.PublicKey;
+
+import javax.crypto.interfaces.DHPrivateKey;
+import javax.crypto.interfaces.DHPublicKey;
+
+import org.spongycastle.crypto.params.AsymmetricKeyParameter;
+import org.spongycastle.crypto.params.ElGamalParameters;
+import org.spongycastle.crypto.params.ElGamalPrivateKeyParameters;
+import org.spongycastle.crypto.params.ElGamalPublicKeyParameters;
+import org.spongycastle.jce.interfaces.ElGamalPrivateKey;
+import org.spongycastle.jce.interfaces.ElGamalPublicKey;
+
+/**
+ * utility class for converting jce/jca ElGamal objects
+ * objects into their org.spongycastle.crypto counterparts.
+ */
+public class ElGamalUtil
+{
+    static public AsymmetricKeyParameter generatePublicKeyParameter(
+        PublicKey    key)
+        throws InvalidKeyException
+    {
+        if (key instanceof ElGamalPublicKey)
+        {
+            ElGamalPublicKey    k = (ElGamalPublicKey)key;
+
+            return new ElGamalPublicKeyParameters(k.getY(),
+                new ElGamalParameters(k.getParameters().getP(), k.getParameters().getG()));
+        }
+        else if (key instanceof DHPublicKey)
+        {
+            DHPublicKey    k = (DHPublicKey)key;
+
+            return new ElGamalPublicKeyParameters(k.getY(),
+                new ElGamalParameters(k.getParams().getP(), k.getParams().getG()));
+        }
+
+        throw new InvalidKeyException("can't identify public key for El Gamal.");
+    }
+
+    static public AsymmetricKeyParameter generatePrivateKeyParameter(
+        PrivateKey    key)
+        throws InvalidKeyException
+    {
+        if (key instanceof ElGamalPrivateKey)
+        {
+            ElGamalPrivateKey    k = (ElGamalPrivateKey)key;
+
+            return new ElGamalPrivateKeyParameters(k.getX(),
+                new ElGamalParameters(k.getParameters().getP(), k.getParameters().getG()));
+        }
+        else if (key instanceof DHPrivateKey)
+        {
+            DHPrivateKey    k = (DHPrivateKey)key;
+
+            return new ElGamalPrivateKeyParameters(k.getX(),
+                new ElGamalParameters(k.getParams().getP(), k.getParams().getG()));
+        }
+                        
+        throw new InvalidKeyException("can't identify private key for El Gamal.");
+    }
+}