1 files changed, 103 insertions, 0 deletions
diff --git a/java/src/main/java/org/whispersystems/libaxolotl/ecc/Curve.java b/java/src/main/java/org/whispersystems/libaxolotl/ecc/Curve.java
new file mode 100644
index 00000000..5d47e3aa
--- /dev/null
+++ b/java/src/main/java/org/whispersystems/libaxolotl/ecc/Curve.java
@@ -0,0 +1,103 @@
+/**
+ * Copyright (C) 2013 Open Whisper Systems
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.whispersystems.libaxolotl.ecc;
+
+import org.whispersystems.curve25519.Curve25519KeyPair;
+import org.whispersystems.libaxolotl.InvalidKeyException;
+import org.whispersystems.curve25519.Curve25519;
+
+import java.security.NoSuchAlgorithmException;
+import java.security.SecureRandom;
+
+public class Curve {
+
+  public  static final int DJB_TYPE   = 0x05;
+
+  public static boolean isNative() {
+    return Curve25519.isNative();
+  }
+
+  public static ECKeyPair generateKeyPair() {
+    SecureRandom      secureRandom = getSecureRandom();
+    Curve25519KeyPair keyPair      = Curve25519.generateKeyPair(secureRandom);
+
+    return new ECKeyPair(new DjbECPublicKey(keyPair.getPublicKey()),
+                         new DjbECPrivateKey(keyPair.getPrivateKey()));
+  }
+
+  public static ECPublicKey decodePoint(byte[] bytes, int offset)
+      throws InvalidKeyException
+  {
+    int type = bytes[offset] & 0xFF;
+
+    switch (type) {
+      case Curve.DJB_TYPE:
+        byte[] keyBytes = new byte[32];
+        System.arraycopy(bytes, offset+1, keyBytes, 0, keyBytes.length);
+        return new DjbECPublicKey(keyBytes);
+      default:
+        throw new InvalidKeyException("Bad key type: " + type);
+    }
+  }
+
+  public static ECPrivateKey decodePrivatePoint(byte[] bytes) {
+    return new DjbECPrivateKey(bytes);
+  }
+
+  public static byte[] calculateAgreement(ECPublicKey publicKey, ECPrivateKey privateKey)
+      throws InvalidKeyException
+  {
+    if (publicKey.getType() != privateKey.getType()) {
+      throw new InvalidKeyException("Public and private keys must be of the same type!");
+    }
+
+    if (publicKey.getType() == DJB_TYPE) {
+      return Curve25519.calculateAgreement(((DjbECPublicKey)publicKey).getPublicKey(),
+                                           ((DjbECPrivateKey)privateKey).getPrivateKey());
+    } else {
+      throw new InvalidKeyException("Unknown type: " + publicKey.getType());
+    }
+  }
+
+  public static boolean verifySignature(ECPublicKey signingKey, byte[] message, byte[] signature)
+      throws InvalidKeyException
+  {
+    if (signingKey.getType() == DJB_TYPE) {
+      return Curve25519.verifySignature(((DjbECPublicKey)signingKey).getPublicKey(), message, signature);
+    } else {
+      throw new InvalidKeyException("Unknown type: " + signingKey.getType());
+    }
+  }
+
+  public static byte[] calculateSignature(ECPrivateKey signingKey, byte[] message)
+      throws InvalidKeyException
+  {
+    if (signingKey.getType() == DJB_TYPE) {
+      return Curve25519.calculateSignature(getSecureRandom(), ((DjbECPrivateKey)signingKey).getPrivateKey(), message);
+    } else {
+      throw new InvalidKeyException("Unknown type: " + signingKey.getType());
+    }
+  }
+
+  private static SecureRandom getSecureRandom() {
+    try {
+      return SecureRandom.getInstance("SHA1PRNG");
+    } catch (NoSuchAlgorithmException e) {
+      throw new AssertionError(e);
+    }
+  }
+}