1 files changed, 78 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/crypto/tls/DefaultTlsAgreementCredentials.java b/core/src/main/java/org/spongycastle/crypto/tls/DefaultTlsAgreementCredentials.java
new file mode 100644
index 00000000..be981d8a
--- /dev/null
+++ b/core/src/main/java/org/spongycastle/crypto/tls/DefaultTlsAgreementCredentials.java
@@ -0,0 +1,78 @@
+package org.spongycastle.crypto.tls;
+
+import java.math.BigInteger;
+
+import org.spongycastle.crypto.BasicAgreement;
+import org.spongycastle.crypto.agreement.DHBasicAgreement;
+import org.spongycastle.crypto.agreement.ECDHBasicAgreement;
+import org.spongycastle.crypto.params.AsymmetricKeyParameter;
+import org.spongycastle.crypto.params.DHPrivateKeyParameters;
+import org.spongycastle.crypto.params.ECPrivateKeyParameters;
+import org.spongycastle.util.BigIntegers;
+
+public class DefaultTlsAgreementCredentials
+    extends AbstractTlsAgreementCredentials
+{
+    protected Certificate certificate;
+    protected AsymmetricKeyParameter privateKey;
+
+    protected BasicAgreement basicAgreement;
+    protected boolean truncateAgreement;
+
+    public DefaultTlsAgreementCredentials(Certificate certificate, AsymmetricKeyParameter privateKey)
+    {
+        if (certificate == null)
+        {
+            throw new IllegalArgumentException("'certificate' cannot be null");
+        }
+        if (certificate.isEmpty())
+        {
+            throw new IllegalArgumentException("'certificate' cannot be empty");
+        }
+        if (privateKey == null)
+        {
+            throw new IllegalArgumentException("'privateKey' cannot be null");
+        }
+        if (!privateKey.isPrivate())
+        {
+            throw new IllegalArgumentException("'privateKey' must be private");
+        }
+
+        if (privateKey instanceof DHPrivateKeyParameters)
+        {
+            basicAgreement = new DHBasicAgreement();
+            truncateAgreement = true;
+        }
+        else if (privateKey instanceof ECPrivateKeyParameters)
+        {
+            basicAgreement = new ECDHBasicAgreement();
+            truncateAgreement = false;
+        }
+        else
+        {
+            throw new IllegalArgumentException("'privateKey' type not supported: "
+                + privateKey.getClass().getName());
+        }
+
+        this.certificate = certificate;
+        this.privateKey = privateKey;
+    }
+
+    public Certificate getCertificate()
+    {
+        return certificate;
+    }
+
+    public byte[] generateAgreement(AsymmetricKeyParameter peerPublicKey)
+    {
+        basicAgreement.init(privateKey);
+        BigInteger agreementValue = basicAgreement.calculateAgreement(peerPublicKey);
+
+        if (truncateAgreement)
+        {
+            return BigIntegers.asUnsignedByteArray(agreementValue);
+        }
+
+        return BigIntegers.asUnsignedByteArray(basicAgreement.getFieldSize(), agreementValue);
+    }
+}