33 lines
1.3 KiB
Dart
33 lines
1.3 KiB
Dart
import 'dart:convert';
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import 'dart:typed_data';
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import 'package:crypto/crypto.dart';
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import 'package:encrypt/encrypt.dart';
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/// 新版本解密（项目自定义协议：12 字节 nonce + sha256 派生 key/iv + AES-CBC）
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String aesDecryptEx(String cipher, String key) {
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// final t1 = DateTime.now();
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const nonceLen = 12;
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final cipherBytes = base64Decode(cipher);
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final nonce = cipherBytes.sublist(0, nonceLen);
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final largeShaRaw = [...utf8.encode(key), ...nonce];
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final largeShaRawMid = largeShaRaw.length ~/ 2;
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final msgKeyLarge = sha256.convert(largeShaRaw).bytes;
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final msgKey = msgKeyLarge.sublist(8, 24);
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final shaRawA = [...msgKey, ...largeShaRaw.sublist(0, largeShaRawMid)];
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final sha256a = sha256.convert(shaRawA).bytes;
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final shaRawB = [...largeShaRaw.sublist(largeShaRawMid), ...msgKey];
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final sha256b = sha256.convert(shaRawB).bytes;
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final aesKey = [...sha256a.sublist(0, 8), ...sha256b.sublist(8, 24), ...sha256a.sublist(24)];
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final aesIV = [...sha256b.sublist(0, 4), ...sha256a.sublist(12, 20), ...sha256b.sublist(28)];
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final encrypter = Encrypter(AES(Key(Uint8List.fromList(aesKey)), mode: AESMode.cbc));
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final decrypted = encrypter.decryptBytes(Encrypted(cipherBytes.sublist(nonceLen)), iv: IV(Uint8List.fromList(aesIV)));
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final text = const Utf8Decoder().convert(decrypted);
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return text;
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}
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