feat(crypto): Introduce separate crypto-only module

Author: harrytmthy

safebox-crypto/.gitignore

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

safebox-crypto/build.gradle.kts

@@ -0,0 +1,111 @@
+/*
+ * Copyright 2025 Harry Timothy Tumalewa
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import com.vanniktech.maven.publish.SonatypeHost
+
+plugins {
+    id("com.android.library")
+    id("org.jetbrains.kotlin.android")
+    id("org.jetbrains.dokka")
+    id("com.vanniktech.maven.publish")
+}
+
+group = "io.github.harrytmthy"
+version = "1.3.0-alpha01"
+
+android {
+    namespace = "com.harrytmthy.safebox.cryptography"
+    compileSdk = 36
+
+    defaultConfig {
+        minSdk = 23
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        consumerProguardFiles("proguard-consumer-rules.pro")
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_11
+        targetCompatibility = JavaVersion.VERSION_11
+    }
+
+    kotlinOptions {
+        jvmTarget = "11"
+    }
+}
+
+dependencies {
+    implementation(libs.androidx.annotation)
+    implementation(libs.bouncy.castle.provider)
+
+    androidTestImplementation(libs.androidx.test.ext)
+    androidTestImplementation(libs.androidx.test.runner)
+    androidTestImplementation(libs.kotlin.test)
+}
+
+dokka {
+    dokkaSourceSets {
+        configureEach {
+            includes.from("README.md")
+        }
+    }
+}
+
+tasks.register<Jar>("sourcesJar") {
+    archiveClassifier.set("sources")
+    from(android.sourceSets["main"].java.srcDirs)
+}
+
+tasks.register<Jar>("javadocJar") {
+    dependsOn("dokkaJavadoc")
+    archiveClassifier.set("javadoc")
+    from(tasks.named("dokkaJavadoc").map { it.outputs.files })
+}
+
+mavenPublishing {
+    publishToMavenCentral(SonatypeHost.CENTRAL_PORTAL)
+    signAllPublications()
+
+    pom {
+        name.set("SafeBox Crypto")
+        description.set("Cryptography core used by SafeBox, including ChaCha20-Poly1305 and AES-GCM keystore wrapping.")
+        url.set("https://github.com/harrytmthy/safebox")
+
+        licenses {
+            license {
+                name.set("MIT License")
+                url.set("https://opensource.org/licenses/MIT")
+            }
+        }
+
+        developers {
+            developer {
+                id.set("harrytmthy")
+                name.set("Harry Timothy Tumalewa")
+                email.set("harrytmthy@gmail.com")
+            }
+        }
+        scm {
+            connection.set("scm:git:git://github.com/harrytmthy/safebox.git")
+            developerConnection.set("scm:git:ssh://github.com:harrytmthy/safebox.git")
+            url.set("https://github.com/harrytmthy/safebox")
+        }
+    }
+}

safebox/proguard-consumer-rules.pro renamed to safebox-crypto/proguard-consumer-rules.pro

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     Copyright 2025 Harry Timothy Tumalewa
+
+     Licensed under the Apache License, Version 2.0 (the "License");
+     you may not use this file except in compliance with the License.
+     You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+     Unless required by applicable law or agreed to in writing, software
+     distributed under the License is distributed on an "AS IS" BASIS,
+     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+     See the License for the specific language governing permissions and
+     limitations under the License.
+-->
+<manifest />

safebox/src/androidTest/java/com/harrytmthy/safebox/cryptography/AesGcmCipherProviderTest.kt renamed to safebox-crypto/src/androidTest/java/com/harrytmthy/safebox/cryptography/AesGcmCipherProviderTest.kt

@@ -21,7 +21,6 @@ import android.security.keystore.KeyProperties.ENCRYPTION_PADDING_NONE
 import android.security.keystore.KeyProperties.KEY_ALGORITHM_AES
 import android.security.keystore.KeyProperties.PURPOSE_DECRYPT
 import android.security.keystore.KeyProperties.PURPOSE_ENCRYPT
-import com.harrytmthy.safebox.extensions.requireAes
 import com.harrytmthy.safebox.keystore.AndroidKeyStoreKeyProvider
 import com.harrytmthy.safebox.keystore.KeyProvider
 import javax.crypto.Cipher
@@ -44,7 +43,7 @@ internal class AesGcmCipherProvider private constructor(
 
     override fun encrypt(plaintext: ByteArray): ByteArray {
         val key = keyProvider.getOrCreateKey()
-        requireAes(key)
+        check(key.algorithm == KEY_ALGORITHM_AES) { "Only AES keys are supported" }
         val cipher = Cipher.getInstance(TRANSFORMATION)
         cipher.init(Cipher.ENCRYPT_MODE, key)
         aad?.let(cipher::updateAAD)
@@ -55,7 +54,7 @@ internal class AesGcmCipherProvider private constructor(
 
     override fun decrypt(ciphertext: ByteArray): ByteArray {
         val key = keyProvider.getOrCreateKey()
-        requireAes(key)
+        check(key.algorithm == KEY_ALGORITHM_AES) { "Only AES keys are supported" }
         val iv = ciphertext.copyOfRange(0, IV_SIZE)
         val actualData = ciphertext.copyOfRange(IV_SIZE, ciphertext.size)
         val spec = GCMParameterSpec(GCM_TAG_LENGTH_BITS, iv)