1 files changed, 43 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/crypto/generators/ElGamalParametersGenerator.java b/core/src/main/java/org/spongycastle/crypto/generators/ElGamalParametersGenerator.java
new file mode 100644
index 00000000..863a8f4a
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/crypto/generators/ElGamalParametersGenerator.java
@@ -0,0 +1,43 @@
+package org.spongycastle.crypto.generators;
+
+import org.spongycastle.crypto.params.ElGamalParameters;
+
+import java.math.BigInteger;
+import java.security.SecureRandom;
+
+public class ElGamalParametersGenerator
+{
+    private int             size;
+    private int             certainty;
+    private SecureRandom    random;
+
+    public void init(
+        int             size,
+        int             certainty,
+        SecureRandom    random)
+    {
+        this.size = size;
+        this.certainty = certainty;
+        this.random = random;
+    }
+
+    /**
+     * which generates the p and g values from the given parameters,
+     * returning the ElGamalParameters object.
+     * <p>
+     * Note: can take a while...
+     */
+    public ElGamalParameters generateParameters()
+    {
+        //
+        // find a safe prime p where p = 2*q + 1, where p and q are prime.
+        //
+        BigInteger[] safePrimes = DHParametersHelper.generateSafePrimes(size, certainty, random);
+
+        BigInteger p = safePrimes[0];
+        BigInteger q = safePrimes[1];
+        BigInteger g = DHParametersHelper.selectGenerator(p, q, random);
+
+        return new ElGamalParameters(p, g);
+    }
+}