1 files changed, 113 insertions, 0 deletions
diff --git a/pg/src/main/java/org/spongycastle/bcpg/ECDHPublicBCPGKey.java b/pg/src/main/java/org/spongycastle/bcpg/ECDHPublicBCPGKey.java
new file mode 100644
index 00000000..a1ddfffb
--- /dev/null
+++ b/pg/src/main/java/org/spongycastle/bcpg/ECDHPublicBCPGKey.java
@@ -0,0 +1,113 @@
+package org.spongycastle.bcpg;
+
+import java.io.IOException;
+
+import org.spongycastle.asn1.ASN1ObjectIdentifier;
+import org.spongycastle.math.ec.ECPoint;
+
+/**
+ * base class for an ECDH Public Key.
+ */
+public class ECDHPublicBCPGKey
+    extends ECPublicBCPGKey
+{
+    private byte reserved;
+    private byte hashFunctionId;
+    private byte symAlgorithmId;
+
+    /**
+     * @param in the stream to read the packet from.
+     */
+    public ECDHPublicBCPGKey(
+        BCPGInputStream in)
+        throws IOException
+    {
+        super(in);
+
+        int length = in.read();
+        byte[] kdfParameters =  new byte[length];
+        if (kdfParameters.length != 3)
+        {
+            throw new IllegalStateException("kdf parameters size of 3 expected.");
+        }
+
+        in.read(kdfParameters);
+
+        reserved = kdfParameters[0];
+        hashFunctionId = kdfParameters[1];
+        symAlgorithmId = kdfParameters[2];
+
+        verifyHashAlgorithm();
+        verifySymmetricKeyAlgorithm();
+    }
+
+    public ECDHPublicBCPGKey(
+        ASN1ObjectIdentifier oid,
+        ECPoint point,
+        int hashAlgorithm,
+        int symmetricKeyAlgorithm)
+    {
+        super(oid, point);
+
+        reserved = 1;
+        hashFunctionId = (byte)hashAlgorithm;
+        symAlgorithmId = (byte)symmetricKeyAlgorithm;
+
+        verifyHashAlgorithm();
+        verifySymmetricKeyAlgorithm();
+    }
+
+    public byte getReserved()
+    {
+        return reserved;
+    }
+
+    public byte getHashAlgorithm()
+    {
+        return hashFunctionId;
+    }
+
+    public byte getSymmetricKeyAlgorithm()
+    {
+        return symAlgorithmId;
+    }
+
+    public void encode(
+        BCPGOutputStream out)
+        throws IOException
+    {
+        super.encode(out);
+        out.write(0x3);
+        out.write(reserved);
+        out.write(hashFunctionId);
+        out.write(symAlgorithmId);
+    }
+
+    private void verifyHashAlgorithm()
+    {
+        switch (hashFunctionId)
+        {
+        case HashAlgorithmTags.SHA256:
+        case HashAlgorithmTags.SHA384:
+        case HashAlgorithmTags.SHA512:
+            break;
+
+        default:
+            throw new IllegalStateException("Hash algorithm must be SHA-256 or stronger.");
+        }
+    }
+
+    private void verifySymmetricKeyAlgorithm()
+    {
+        switch (symAlgorithmId)
+        {
+        case SymmetricKeyAlgorithmTags.AES_128:
+        case SymmetricKeyAlgorithmTags.AES_192:
+        case SymmetricKeyAlgorithmTags.AES_256:
+            break;
+
+        default:
+            throw new IllegalStateException("Symmetric key algorithm must be AES-128 or stronger.");
+        }
+    }
+}