Add utility class for SRP

1 files changed, 51 insertions, 0 deletions

diff --git a/core/src/main/java/org/bouncycastle/crypto/tls/TlsSRPUtils.java b/core/src/main/java/org/bouncycastle/crypto/tls/TlsSRPUtils.java
new file mode 100644
index 00000000..427f2661
--- /dev/null
+++ b/core/src/main/java/org/bouncycastle/crypto/tls/TlsSRPUtils.java
@@ -0,0 +1,51 @@
+package org.bouncycastle.crypto.tls;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.util.Hashtable;
+
+import org.bouncycastle.util.Integers;
+
+public class TlsSRPUtils
+{
+    public static final Integer EXT_SRP = Integers.valueOf(ExtensionType.srp);
+
+    public static void addSRPExtension(Hashtable extensions, byte[] identity) throws IOException
+    {
+        extensions.put(EXT_SRP, createSRPExtension(identity));
+    }
+
+    public static byte[] getSRPExtension(Hashtable extensions) throws IOException
+    {
+        byte[] extensionData = TlsUtils.getExtensionData(extensions, EXT_SRP);
+        return extensionData == null ? null : readSRPExtension(extensionData);
+    }
+
+    public static byte[] createSRPExtension(byte[] identity) throws IOException
+    {
+        if (identity == null)
+        {
+            throw new TlsFatalAlert(AlertDescription.internal_error);
+        }
+
+        ByteArrayOutputStream buf = new ByteArrayOutputStream();
+        TlsUtils.writeOpaque8(identity, buf);
+        return buf.toByteArray();
+    }
+
+    public static byte[] readSRPExtension(byte[] extensionData) throws IOException
+    {
+        if (extensionData == null)
+        {
+            throw new IllegalArgumentException("'extensionData' cannot be null");
+        }
+
+        ByteArrayInputStream buf = new ByteArrayInputStream(extensionData);
+        byte[] identity = TlsUtils.readOpaque8(buf);
+
+        TlsProtocol.assertEmpty(buf);
+
+        return identity;
+    }
+}