From b95c88b7082b1d46eea34508fe704ef7e724f2d0 Mon Sep 17 00:00:00 2001
From: Hugo Pointcheval <hugo@gitlab.pointcheval.fr>
Date: Sat, 18 Apr 2020 11:28:29 +0200
Subject: [PATCH] Rename api

---
 ...ical_crypto.dart => symmetric_crypto.dart} | 107 +++++++++++-------
 1 file changed, 63 insertions(+), 44 deletions(-)
 rename lib/{symmetrical_crypto.dart => symmetric_crypto.dart} (64%)

diff --git a/lib/symmetrical_crypto.dart b/lib/symmetric_crypto.dart
similarity index 64%
rename from lib/symmetrical_crypto.dart
rename to lib/symmetric_crypto.dart
index 38f19e4..437666c 100644
--- a/lib/symmetrical_crypto.dart
+++ b/lib/symmetric_crypto.dart
@@ -11,34 +11,64 @@ enum KeySize { bits128, bits192, bits256 }
 /// Defines all available ciphers.
 enum Cipher { AES }
 
+/// Key Helper
+///
+/// You can generate Secret keys of different sizes.
+class KeyGenerator {
+  /// Generate a secret key.
+  ///
+  /// You can specify a `keySize`. Default is 256 bits.
+  Future<Uint8List> secretKey({KeySize keySize}) async {
+    int size;
+    switch (keySize) {
+      case KeySize.bits128:
+        size = 128;
+        break;
+      case KeySize.bits192:
+        size = 192;
+        break;
+      case KeySize.bits256:
+        size = 256;
+        break;
+      default:
+        // Default size = 256 bits
+        size = 256;
+        break;
+    }
+    return await NativeCrypto().symKeygen(size);
+  }
+}
+
 /// AES Helper
 ///
-/// You can generate AES keys, encrypt and decrypt data.
+/// You can encrypt and decrypt data.
 class AES {
-  /// This key is used for encryption and decryption.
-  Uint8List key;
+  Uint8List _key;
 
   bool _isInitialized = false;
 
-  /// Check if the AES object is intialized with a valid key before perform any operation.
-  bool get isInitialized => _isInitialized;
-
   KeySize _keySize;
 
-  /// Defines the size of the generated or passed key.
-  KeySize get keySize => _keySize;
-  
   /// You can pass a key in constructor.
-  AES({this.key}) {
+  AES({Uint8List key}) {
+    this._key = key;
     try {
-      bool isValidKey = _testKey();
-      this._isInitialized = isValidKey;
+      this._isInitialized = _testKey();
     } on KeyException {
       this._isInitialized = false;
       throw KeyException('Invalid key length: ${this.key.length} Bytes');
     }
   }
 
+  /// This key is used for encryption and decryption.
+  Uint8List get key => this._key;
+
+  /// Check if the AES object is intialized with a valid key before perform any operation.
+  bool get isInitialized => this._isInitialized;
+
+  /// Defines the size of the generated or passed key.
+  KeySize get keySize => this._keySize;
+
   /// [Private]
   /// Tests if the key is valid.
   ///
@@ -66,34 +96,16 @@ class AES {
 
   /// Generate an AES key.
   ///
-  /// You can specify a `keySize`. Default is 256 bits.
+  /// You have to specify a `keySize`.
   /// Return `null` if the key is already set.
-  init({KeySize keySize}) async {
+  init(KeySize keySize) async {
     if (this.key != null) return null;
 
-    int size;
     this._keySize = keySize;
-    
-    switch (keySize) {
-      case KeySize.bits128:
-        size = 128;
-        break;
-      case KeySize.bits192:
-        size = 192;
-        break;
-      case KeySize.bits256:
-        size = 256;
-        break;
-      default:
-        // Default size = 256 bits
-        size = 256;
-        break;
-    }
+    this._key = await KeyGenerator().secretKey(keySize: keySize);
 
-    this.key = await NativeCrypto().symKeygen(size);
     try {
-      bool isValidKey = _testKey();
-      this._isInitialized = isValidKey;
+      this._isInitialized = _testKey();
     } on KeyException {
       this._isInitialized = false;
       throw KeyException('Invalid key length: ${this.key.length} Bytes');
@@ -104,14 +116,18 @@ class AES {
   ///
   /// Takes `Uint8List` data as parameter.
   /// And returns an `Uint8List` **list**.
-  /// 
+  ///
+  /// You can pass a different key.
+  ///
   /// The first member of this list is the `cipher data`,
   /// and the second member is the `IV`.
-  Future<List<Uint8List>> encrypt(Uint8List data) async {
-    if (!this._isInitialized)
-      throw EncryptionException('Instance not initialized.');
+  Future<List<Uint8List>> encrypt(Uint8List data, {Uint8List key}) async {
+    if (!this._isInitialized && key == null)
+      throw EncryptionException(
+          'Instance not initialized. You can pass a key directly in encrypt method.');
+
     List<Uint8List> encryptedPayload =
-        await NativeCrypto().symEncrypt(data, this.key);
+        await NativeCrypto().symEncrypt(data, key ?? this.key);
     return encryptedPayload;
   }
 
@@ -119,11 +135,14 @@ class AES {
   ///
   /// Takes `Uint8List` **list** as parameter.
   /// And returns plain text data as `Uint8List`.
-  Future<Uint8List> decrypt(List<Uint8List> encryptedPayload) async {
-    if (!this._isInitialized)
-      throw DecryptionException('Instance not initialized.');
+  /// 
+  /// You can pass a different key.
+  Future<Uint8List> decrypt(List<Uint8List> encryptedPayload, {Uint8List key}) async {
+    if (!this._isInitialized && key == null)
+      throw DecryptionException(
+          'Instance not initialized. You can pass a key directly in encrypt method.');
     Uint8List decryptedPayload =
-        await NativeCrypto().symDecrypt(encryptedPayload, this.key);
+        await NativeCrypto().symDecrypt(encryptedPayload, key ?? this.key);
     return decryptedPayload;
   }
-}
\ No newline at end of file
+}