1 files changed, 109 insertions, 0 deletions
diff --git a/jni/curve25519-jni.c b/jni/curve25519-jni.c
new file mode 100644
index 00000000..5d058a91
--- /dev/null
+++ b/jni/curve25519-jni.c
@@ -0,0 +1,109 @@
+/**
+ * Copyright (C) 2013-2014 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/>.
+ */
+
+#include <string.h>
+#include <stdint.h>
+
+#include <jni.h>
+#include "curve25519-donna.h"
+#include "curve_sigs.h"
+
+JNIEXPORT jbyteArray JNICALL Java_org_whispersystems_libaxolotl_ecc_Curve25519_generatePrivateKey
+  (JNIEnv *env, jclass clazz, jbyteArray random)
+{
+  uint8_t* privateKey = (uint8_t*)(*env)->GetByteArrayElements(env, random, 0);
+
+  privateKey[0] &= 248;
+  privateKey[31] &= 127;
+  privateKey[31] |= 64;
+
+  (*env)->ReleaseByteArrayElements(env, random, privateKey, 0);
+
+  return random;
+}
+
+JNIEXPORT jbyteArray JNICALL Java_org_whispersystems_libaxolotl_ecc_Curve25519_generatePublicKey
+  (JNIEnv *env, jclass clazz, jbyteArray privateKey)
+{
+    static const uint8_t  basepoint[32] = {9};
+
+    jbyteArray publicKey       = (*env)->NewByteArray(env, 32);
+    uint8_t*   publicKeyBytes  = (uint8_t*)(*env)->GetByteArrayElements(env, publicKey, 0);
+    uint8_t*   privateKeyBytes = (uint8_t*)(*env)->GetByteArrayElements(env, privateKey, 0);
+
+    curve25519_donna(publicKeyBytes, privateKeyBytes, basepoint);
+
+    (*env)->ReleaseByteArrayElements(env, publicKey, publicKeyBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, privateKey, privateKeyBytes, 0);
+
+    return publicKey;
+}
+
+JNIEXPORT jbyteArray JNICALL Java_org_whispersystems_libaxolotl_ecc_Curve25519_calculateAgreement
+  (JNIEnv *env, jclass clazz, jbyteArray privateKey, jbyteArray publicKey)
+{
+    jbyteArray sharedKey       = (*env)->NewByteArray(env, 32);
+    uint8_t*   sharedKeyBytes  = (uint8_t*)(*env)->GetByteArrayElements(env, sharedKey, 0);
+    uint8_t*   privateKeyBytes = (uint8_t*)(*env)->GetByteArrayElements(env, privateKey, 0);
+    uint8_t*   publicKeyBytes  = (uint8_t*)(*env)->GetByteArrayElements(env, publicKey, 0);
+
+    curve25519_donna(sharedKeyBytes, privateKeyBytes, publicKeyBytes);
+
+    (*env)->ReleaseByteArrayElements(env, sharedKey, sharedKeyBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, publicKey, publicKeyBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, privateKey, privateKeyBytes, 0);
+
+    return sharedKey;
+}
+
+JNIEXPORT jbyteArray JNICALL Java_org_whispersystems_libaxolotl_ecc_Curve25519_calculateSignature
+  (JNIEnv *env, jclass clazz, jbyteArray random, jbyteArray privateKey, jbyteArray message)
+{
+    jbyteArray signature       = (*env)->NewByteArray(env, 64);
+    uint8_t*   signatureBytes  = (uint8_t*)(*env)->GetByteArrayElements(env, signature, 0);
+    uint8_t*   randomBytes     = (uint8_t*)(*env)->GetByteArrayElements(env, random, 0);
+    uint8_t*   privateKeyBytes = (uint8_t*)(*env)->GetByteArrayElements(env, privateKey, 0);
+    uint8_t*   messageBytes    = (uint8_t*)(*env)->GetByteArrayElements(env, message, 0);
+    jsize      messageLength   = (*env)->GetArrayLength(env, message);
+
+    int result = curve25519_sign(signatureBytes, privateKeyBytes, messageBytes, messageLength, randomBytes);
+
+    (*env)->ReleaseByteArrayElements(env, signature, signatureBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, random, randomBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, privateKey, privateKeyBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, message, messageBytes, 0);
+
+    if (result == 0) return signature;
+    else             (*env)->ThrowNew(env, (*env)->FindClass(env, "java/lang/AssertionError"), "Signature failed!");
+}
+
+JNIEXPORT jboolean JNICALL Java_org_whispersystems_libaxolotl_ecc_Curve25519_verifySignature
+  (JNIEnv *env, jclass clazz, jbyteArray publicKey, jbyteArray message, jbyteArray signature)
+{
+    uint8_t*   signatureBytes = (uint8_t*)(*env)->GetByteArrayElements(env, signature, 0);
+    uint8_t*   publicKeyBytes = (uint8_t*)(*env)->GetByteArrayElements(env, publicKey, 0);
+    uint8_t*   messageBytes   = (uint8_t*)(*env)->GetByteArrayElements(env, message, 0);
+    jsize      messageLength  = (*env)->GetArrayLength(env, message);
+
+    jboolean result = (curve25519_verify(signatureBytes, publicKeyBytes, messageBytes, messageLength) == 0);
+
+    (*env)->ReleaseByteArrayElements(env, signature, signatureBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, publicKey, publicKeyBytes, 0);
+    (*env)->ReleaseByteArrayElements(env, message, messageBytes, 0);
+
+    return result;
+}