Pin code: add some tests

libraries/cryptography/api/src/main/kotlin/io/element/android/libraries/cryptography/api/AESEncryptionSpecs.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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.
+ */
+
+package io.element.android.libraries.cryptography.api
+
+import android.security.keystore.KeyProperties
+
+object AESEncryptionSpecs {
+    const val BLOCK_MODE = KeyProperties.BLOCK_MODE_GCM
+    const val PADDINGS = KeyProperties.ENCRYPTION_PADDING_NONE
+    const val ALGORITHM = KeyProperties.KEY_ALGORITHM_AES
+    const val KEY_SIZE = 128
+    const val CIPHER_TRANSFORMATION = "$ALGORITHM/$BLOCK_MODE/$PADDINGS"
+}

libraries/cryptography/api/src/main/kotlin/io/element/android/libraries/cryptography/api/EncryptionDecryptionService.kt

@@ -20,10 +20,9 @@ import javax.crypto.Cipher
 import javax.crypto.SecretKey
 
 /**
- * Simple service to provide cryptographic operations.
+ * Simple service to provide encryption and decryption operations.
  */
-interface CryptoService {
-    fun getOrCreateSecretKey(alias: String): SecretKey
+interface EncryptionDecryptionService {
     fun createEncryptionCipher(key: SecretKey): Cipher
     fun createDecryptionCipher(key: SecretKey, initializationVector: ByteArray): Cipher
     fun encrypt(key: SecretKey, input: ByteArray): EncryptionResult

libraries/cryptography/api/src/main/kotlin/io/element/android/libraries/cryptography/api/EncryptionResult.kt

@@ -14,10 +14,13 @@
  * limitations under the License.
  */
 
+@file:OptIn(ExperimentalEncodingApi::class)
+
 package io.element.android.libraries.cryptography.api
 
-import android.util.Base64
 import java.nio.ByteBuffer
+import kotlin.io.encoding.Base64
+import kotlin.io.encoding.ExperimentalEncodingApi
 
 /**
  * Holds the result of an encryption operation.
@@ -34,7 +37,7 @@ class EncryptionResult(
                 .put(initializationVector)
                 .put(encryptedByteArray)
                 .array()
-        return Base64.encodeToString(cipherTextWithIv, Base64.NO_WRAP)
+        return Base64.encode(cipherTextWithIv)
     }
 
     companion object {
@@ -43,7 +46,7 @@ class EncryptionResult(
          * @return the [EncryptionResult] from the base64 representation.
          */
         fun fromBase64(base64: String): EncryptionResult {
-            val cipherTextWithIv = Base64.decode(base64, Base64.NO_WRAP)
+            val cipherTextWithIv = Base64.decode(base64)
             val buffer = ByteBuffer.wrap(cipherTextWithIv)
             val initializationVectorSize = buffer.int
             val initializationVector = ByteArray(initializationVectorSize)

libraries/cryptography/api/src/main/kotlin/io/element/android/libraries/cryptography/api/SecretKeyProvider.kt

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) 2023 New Vector Ltd
+ *
+ * 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.
+ */
+
+package io.element.android.libraries.cryptography.api
+
+import javax.crypto.SecretKey
+
+/**
+ * Simple interface to get or create a secret key for a given alias.
+ * Implementation should be able to store the generated key securely.
+ */
+interface SecretKeyProvider {
+    fun getOrCreateKey(alias: String): SecretKey
+}