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lib/tool/encryption_util.dart

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+import 'dart:convert';
+import 'dart:typed_data';
+import 'package:encrypt/encrypt.dart' as enc;
+import 'package:archive/archive.dart';
+
+class EncryptionUtil {
+  // 固定密钥（和后端保持一致）
+  static const String _keyStr = ",Lscj312.;[]sc`1dsajcjc;;wislacx";
+  static const String _ivStr = ",>ew:[7890;,wd[2";
+
+  // 对外简易方法（你 Service / Provider 里直接用）
+  static String encrypt(String data) => encryptAndCompress(data);
+  static String decrypt(String encryptedBase64) => decompressAndDecrypt(encryptedBase64);
+
+  /// 加密：字符串 → GZIP → AES → Base64
+  static String encryptAndCompress(String plainText) {
+    // 强制 32位 Key / 16位 IV（AES 标准）
+    final key = enc.Key.fromUtf8(_keyStr.padRight(32).substring(0, 32));
+    final iv = enc.IV.fromUtf8(_ivStr.padRight(16).substring(0, 16));
+    final encrypter = enc.Encrypter(enc.AES(key, mode: enc.AESMode.cbc));
+
+    // GZIP 压缩
+    final utf8Bytes = utf8.encode(plainText);
+    final compressed = GZipEncoder().encode(utf8Bytes)!;
+
+    // AES 加密
+    final encrypted = encrypter.encryptBytes(
+      Uint8List.fromList(compressed),
+      iv: iv,
+    );
+
+    return encrypted.base64;
+  }
+
+  /// 解密：Base64 → AES → GZIP → 字符串
+  static String decompressAndDecrypt(String encryptedBase64) {
+    final key = enc.Key.fromUtf8(_keyStr.padRight(32).substring(0, 32));
+    final iv = enc.IV.fromUtf8(_ivStr.padRight(16).substring(0, 16));
+    final encrypter = enc.Encrypter(enc.AES(key, mode: enc.AESMode.cbc));
+
+    // 解密
+    final encrypted = enc.Encrypted.fromBase64(encryptedBase64);
+    final decryptedBytes = encrypter.decryptBytes(encrypted, iv: iv);
+
+    // GZIP 解压
+    final decompressed = GZipDecoder().decodeBytes(decryptedBytes);
+
+    return utf8.decode(decompressed);
+  }
+}