1 files changed, 42 insertions, 0 deletions
diff --git a/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/DHKeyPairGenerator.java b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/DHKeyPairGenerator.java
new file mode 100644
index 000000000..f87b416fa
--- /dev/null
+++ b/libraries/spongycastle/core/src/main/java/org/spongycastle/crypto/generators/DHKeyPairGenerator.java
@@ -0,0 +1,42 @@
+package org.spongycastle.crypto.generators;
+
+import org.spongycastle.crypto.AsymmetricCipherKeyPair;
+import org.spongycastle.crypto.AsymmetricCipherKeyPairGenerator;
+import org.spongycastle.crypto.KeyGenerationParameters;
+import org.spongycastle.crypto.params.DHKeyGenerationParameters;
+import org.spongycastle.crypto.params.DHParameters;
+import org.spongycastle.crypto.params.DHPrivateKeyParameters;
+import org.spongycastle.crypto.params.DHPublicKeyParameters;
+
+import java.math.BigInteger;
+
+/**
+ * a Diffie-Hellman key pair generator.
+ *
+ * This generates keys consistent for use in the MTI/A0 key agreement protocol
+ * as described in "Handbook of Applied Cryptography", Pages 516-519.
+ */
+public class DHKeyPairGenerator
+    implements AsymmetricCipherKeyPairGenerator
+{
+    private DHKeyGenerationParameters param;
+
+    public void init(
+        KeyGenerationParameters param)
+    {
+        this.param = (DHKeyGenerationParameters)param;
+    }
+
+    public AsymmetricCipherKeyPair generateKeyPair()
+    {
+        DHKeyGeneratorHelper helper = DHKeyGeneratorHelper.INSTANCE;
+        DHParameters dhp = param.getParameters();
+
+        BigInteger x = helper.calculatePrivate(dhp, param.getRandom()); 
+        BigInteger y = helper.calculatePublic(dhp, x);
+
+        return new AsymmetricCipherKeyPair(
+            new DHPublicKeyParameters(y, dhp),
+            new DHPrivateKeyParameters(x, dhp));
+    }
+}