Add encryption stream

Author: SessionHero01

gradle/libs.versions.toml

@@ -3,6 +3,10 @@ agp = "8.12.0"
 kotlin = "2.2.0"
 
 [libraries]
+junit = { module = "junit:junit", version = "4.13.2" }
+androidx-test-runner = { module = "androidx.test:runner", version = "1.7.0" }
+androidx-test-rules = { module = "androidx.test:rules", version = "1.7.0" }
+androidx-test-ext = { module = "androidx.test.ext:junit", version = "1.3.0" }
 
 [plugins]
 android-library = { id = "com.android.library", version.ref = "agp" }

library/build.gradle.kts

@@ -94,4 +94,8 @@ publishing {
 }
 
 dependencies {
+    androidTestImplementation(libs.junit)
+    androidTestImplementation(libs.androidx.test.runner)
+    androidTestImplementation(libs.androidx.test.rules)
+    androidTestImplementation(libs.androidx.test.ext)
 }

library/src/androidTest/kotlin/network/loki/messenger/libsession_util/EncryptionStreamTest.kt

@@ -0,0 +1,53 @@
+package network.loki.messenger.libsession_util
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import network.loki.messenger.libsession_util.encrypt.DecryptionStream
+import network.loki.messenger.libsession_util.encrypt.EncryptionStream
+import org.junit.Assert.assertArrayEquals
+import org.junit.Test
+import org.junit.runner.RunWith
+import java.io.ByteArrayInputStream
+import java.io.ByteArrayOutputStream
+import java.security.SecureRandom
+
+@RunWith(AndroidJUnit4::class)
+class EncryptionStreamTest {
+
+    private fun testEncryptionCase(
+        chunkSize: Int,
+        dataSize: Int,
+    ) {
+        try {
+            val key = ByteArray(32)
+            SecureRandom().nextBytes(key)
+
+            val expectData = ByteArray(dataSize)
+            SecureRandom().nextBytes(expectData)
+
+            val encrypted = ByteArrayOutputStream().let { outputStream ->
+                EncryptionStream(outputStream, key, chunkSize).use {
+                    it.write(expectData)
+                }
+
+                outputStream.toByteArray()
+            }
+
+            val actualData = DecryptionStream(
+                ByteArrayInputStream(encrypted),
+                key
+            ).use { it.readAllBytes() }
+
+            assertArrayEquals(expectData, actualData)
+        } catch (e: Exception) {
+            throw RuntimeException("Encryption/Decryption failed for chunkSize: $chunkSize, dataSize: $dataSize", e)
+        }
+    }
+
+    @Test
+    fun shouldEncryptDecrypt() {
+        testEncryptionCase(chunkSize = 24, dataSize = 25)
+        testEncryptionCase(chunkSize = 24, dataSize = 24)
+        testEncryptionCase(chunkSize = 24, dataSize = 12)
+        testEncryptionCase(chunkSize = 24, dataSize = 48)
+    }
+}

library/src/main/cpp/encryption.cpp

@@ -179,7 +179,7 @@ Java_network_loki_messenger_libsession_1util_encrypt_EncryptionStream_00024Compa
 
     auto state = std::make_unique<crypto_secretstream_xchacha20poly1305_state>();
     crypto_secretstream_xchacha20poly1305_init_push(state.get(),
-                                                    reinterpret_cast<unsigned char*>(env->GetDirectBufferAddress(javaHeaderOut)),
+                                                    headerOut.get().data(),
                                                     key.get().data());
 
     return reinterpret_cast<jlong>(state.release());
@@ -272,12 +272,11 @@ Java_network_loki_messenger_libsession_1util_encrypt_DecryptionStream_00024Compa
     JavaByteArrayRef in_buf(env, java_in_buf);
 
     unsigned long long mlen = out_buf.get().size();
-    unsigned char tag;
 
     if (crypto_secretstream_xchacha20poly1305_pull(
             reinterpret_cast<crypto_secretstream_xchacha20poly1305_state*>(native_state_ptr),
             out_buf.get().data(), &mlen, // Plaintext data out
-            &tag,
+            nullptr, // Tag (not used here)
             in_buf.get().data(), in_buf_len, // Ciphertext data in
             nullptr, 0 // Additional data (not used here)
             )) {

library/src/main/java/network/loki/messenger/libsession_util/encrypt/DecryptionStream.kt

@@ -28,6 +28,7 @@ class DecryptionStream(
             ))
 
             plaintextBuffer = ByteBuffer.allocate(chunkSize)
+            plaintextBuffer.limit(0) // Should be empty initially
 
             // Read the initial header from the input stream
             check(inStream.read(cipherBuffer, 0, EncryptionStream.encryptionStreamHeaderSize())

library/src/main/java/network/loki/messenger/libsession_util/encrypt/EncryptionStream.kt

@@ -87,6 +87,10 @@ class EncryptionStream(
 
 
     companion object {
+        init {
+            System.loadLibrary("session_util")
+        }
+
         external fun encryptionStreamHeaderSize(): Int
         external fun encryptionStreamChunkOverhead(): Int