Create project

androidhkdf/.gitignore

@@ -0,0 +1 @@
+/build

androidhkdf/build.gradle

@@ -0,0 +1,44 @@
+apply plugin: 'com.android.library'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-android-extensions'
+
+android {
+    compileSdkVersion 29
+    buildToolsVersion "29.0.2"
+
+    defaultConfig {
+        minSdkVersion 16
+        targetSdkVersion 29
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        consumerProguardFiles 'consumer-rules.pro'
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+
+}
+
+repositories {
+    maven {
+        url  "https://dl.bintray.com/terl/lazysodium-maven"
+    }
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+    implementation 'androidx.core:core-ktx:1.2.0'
+    testImplementation 'junit:junit:4.12'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    implementation "com.goterl.lazycode:lazysodium-android:4.1.0@aar"
+    implementation 'net.java.dev.jna:jna:5.5.0@aar'
+}

androidhkdf/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

androidhkdf/src/androidTest/java/com/ticeapp/androidhkdf/ExampleInstrumentedTest.kt

@@ -0,0 +1,24 @@
+package com.ticeapp.androidhkdf
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.ticeapp.androidhkdf.test", appContext.packageName)
+    }
+}

androidhkdf/src/main/AndroidManifest.xml

@@ -0,0 +1,2 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.ticeapp.androidhkdf" />

androidhkdf/src/main/java/com/ticeapp/androidhkdf/HKDF.kt

@@ -0,0 +1,47 @@
+package com.ticeapp.androidhkdf
+
+import com.goterl.lazycode.lazysodium.LazySodiumAndroid
+import com.goterl.lazycode.lazysodium.SodiumAndroid
+import com.goterl.lazycode.lazysodium.exceptions.SodiumException
+import com.goterl.lazycode.lazysodium.interfaces.Auth
+
+fun deriveHKDFKey(ikm: ByteArray, salt: ByteArray? = null, info: String = "", L: Int): ByteArray {
+    val sodium = LazySodiumAndroid(SodiumAndroid())
+
+    val hashOutputLength = Auth.BYTES
+
+    val saltBytes = salt ?: ByteArray(hashOutputLength)
+
+    if (L > 255 * hashOutputLength)
+        throw IllegalArgumentException("Invalid parameter 'L'")
+
+    if (saltBytes.size != Auth.KEYBYTES)
+        throw IllegalArgumentException("Invalid parameter 'salt'")
+
+    // Step 1: Extract
+    val prk = ByteArray(hashOutputLength)
+    if (!sodium.cryptoAuth(prk, ikm, ikm.size.toLong(), saltBytes)) {
+        throw SodiumException("Extraction step failed.")
+    }
+
+    // Step 2: Expand
+    val N = (L + hashOutputLength - 1) / hashOutputLength // equivalent to rounding up L/hashOutputLength
+    var T = ByteArray(0)
+
+    var lastTi = ByteArray(0)
+    for (i in 0 until N) {
+        var message = lastTi.clone()
+        message += sodium.bytes(info)
+        message += i.toByte()
+
+        val currentTi = ByteArray(hashOutputLength)
+        if (!sodium.cryptoAuth(currentTi, message, message.size.toLong(), prk)) {
+            throw SodiumException("Expanding step failed.")
+        }
+
+        T += currentTi
+        lastTi = currentTi
+    }
+
+    return T.slice(0..L-1).toByteArray()
+}

app/.gitignore

@@ -0,0 +1 @@
+/build

app/build.gradle

@@ -0,0 +1,46 @@
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply plugin: 'kotlin-android-extensions'
+
+android {
+    compileSdkVersion 29
+    buildToolsVersion "29.0.2"
+
+    defaultConfig {
+        applicationId "com.ticeapp.androidhkdfapp"
+        minSdkVersion 16
+        targetSdkVersion 29
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+
+}
+
+repositories {
+    maven {
+        url  "https://dl.bintray.com/terl/lazysodium-maven"
+    }
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+    implementation 'androidx.appcompat:appcompat:1.1.0'
+    implementation 'androidx.core:core-ktx:1.2.0'
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    testImplementation 'junit:junit:4.12'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
+    implementation project(":androidhkdf")
+    implementation "com.goterl.lazycode:lazysodium-android:4.1.0@aar"
+    implementation 'net.java.dev.jna:jna:5.5.0@aar'
+}

app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile