1 files changed, 131 insertions, 0 deletions
diff --git a/libraries/spongycastle/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/elgamal/AlgorithmParametersSpi.java b/libraries/spongycastle/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/elgamal/AlgorithmParametersSpi.java
new file mode 100644
index 000000000..41b9a60fd
--- /dev/null
+++ b/libraries/spongycastle/prov/src/main/java/org/spongycastle/jcajce/provider/asymmetric/elgamal/AlgorithmParametersSpi.java
@@ -0,0 +1,131 @@
+package org.spongycastle.jcajce.provider.asymmetric.elgamal;
+
+import java.io.IOException;
+import java.security.spec.AlgorithmParameterSpec;
+import java.security.spec.InvalidParameterSpecException;
+
+import javax.crypto.spec.DHParameterSpec;
+
+import org.spongycastle.asn1.ASN1Encoding;
+import org.spongycastle.asn1.ASN1Primitive;
+import org.spongycastle.asn1.ASN1Sequence;
+import org.spongycastle.asn1.oiw.ElGamalParameter;
+import org.spongycastle.jcajce.provider.symmetric.util.BaseAlgorithmParameters;
+import org.spongycastle.jce.spec.ElGamalParameterSpec;
+
+public class AlgorithmParametersSpi
+    extends BaseAlgorithmParameters
+{
+    ElGamalParameterSpec currentSpec;
+
+    /**
+     * Return the X.509 ASN.1 structure ElGamalParameter.
+     * <p/>
+     * <pre>
+     *  ElGamalParameter ::= SEQUENCE {
+     *                   prime INTEGER, -- p
+     *                   base INTEGER, -- g}
+     * </pre>
+     */
+    protected byte[] engineGetEncoded()
+    {
+        ElGamalParameter elP = new ElGamalParameter(currentSpec.getP(), currentSpec.getG());
+
+        try
+        {
+            return elP.getEncoded(ASN1Encoding.DER);
+        }
+        catch (IOException e)
+        {
+            throw new RuntimeException("Error encoding ElGamalParameters");
+        }
+    }
+
+    protected byte[] engineGetEncoded(
+        String format)
+    {
+        if (isASN1FormatString(format) || format.equalsIgnoreCase("X.509"))
+        {
+            return engineGetEncoded();
+        }
+
+        return null;
+    }
+
+    protected AlgorithmParameterSpec localEngineGetParameterSpec(
+        Class paramSpec)
+        throws InvalidParameterSpecException
+    {
+        if (paramSpec == ElGamalParameterSpec.class)
+        {
+            return currentSpec;
+        }
+        else if (paramSpec == DHParameterSpec.class)
+        {
+            return new DHParameterSpec(currentSpec.getP(), currentSpec.getG());
+        }
+
+        throw new InvalidParameterSpecException("unknown parameter spec passed to ElGamal parameters object.");
+    }
+
+    protected void engineInit(
+        AlgorithmParameterSpec paramSpec)
+        throws InvalidParameterSpecException
+    {
+        if (!(paramSpec instanceof ElGamalParameterSpec) && !(paramSpec instanceof DHParameterSpec))
+        {
+            throw new InvalidParameterSpecException("DHParameterSpec required to initialise a ElGamal algorithm parameters object");
+        }
+
+        if (paramSpec instanceof ElGamalParameterSpec)
+        {
+            this.currentSpec = (ElGamalParameterSpec)paramSpec;
+        }
+        else
+        {
+            DHParameterSpec s = (DHParameterSpec)paramSpec;
+
+            this.currentSpec = new ElGamalParameterSpec(s.getP(), s.getG());
+        }
+    }
+
+    protected void engineInit(
+        byte[] params)
+        throws IOException
+    {
+        try
+        {
+            ElGamalParameter elP = new ElGamalParameter((ASN1Sequence)ASN1Primitive.fromByteArray(params));
+
+            currentSpec = new ElGamalParameterSpec(elP.getP(), elP.getG());
+        }
+        catch (ClassCastException e)
+        {
+            throw new IOException("Not a valid ElGamal Parameter encoding.");
+        }
+        catch (ArrayIndexOutOfBoundsException e)
+        {
+            throw new IOException("Not a valid ElGamal Parameter encoding.");
+        }
+    }
+
+    protected void engineInit(
+        byte[] params,
+        String format)
+        throws IOException
+    {
+        if (isASN1FormatString(format) || format.equalsIgnoreCase("X.509"))
+        {
+            engineInit(params);
+        }
+        else
+        {
+            throw new IOException("Unknown parameter format " + format);
+        }
+    }
+
+    protected String engineToString()
+    {
+        return "ElGamal Parameters";
+    }
+}