Flutter数据加密插件prefix_encrypt的使用

Flutter数据加密插件prefix_encrypt的使用

简介

prefix_encrypt 是一个 Dart 包，允许使用 AEAD XChaCha20 Poly1305 和 XChaCha20 对文本进行加密，并在加密文本中添加前缀以处理 ASCII 表中超过255的符号。这确保这些符号在解密时能被正确处理。

示例：

import 'package:flutter/cupertino.dart';
import 'package:prefix_encrypt/prefix_encrypt.dart';

void main() async {
  // 所有值必须为十六进制

  String key = "0000000000000000000000000000000000000000000000000000000000000000"; // 必须为64个字符
  String nonce = "000000000000000000000000000000000000000000000000"; // 必须为48个字符
  String plaintext = "Hello World!😄";
  String encrypt = await XChaCha20withPrefix.encrypt(key: key, nonce: nonce, plaintext: plaintext);

  debugPrint(encrypt);
  // 输出 "49aaacbbdd0ebb45e2a996a9d95b3f1f806acd5a60886ea9"
  // 解密后的文本: "Hello World!😄"
  // 解密后的文本带前缀: 14:28.6:;Hello World!😄
}

由于解密总是在两个对一组进行处理，因此具有超过两个十六进制位的符号也会被分成两组。例如，💚（01F49A）会变成 01 F4 9A。为了避免这种情况，会在文本的开头添加前缀，以指示符号的位置及其长度。例如：“28.6:”。第一个数字表示位数，第二个数字表示符号在十六进制中的长度。如果没有更多符号或没有符号，则前缀以分号结束。

AEAD XChaCha20 Poly1305 和 XChaCha 的算法来自以下资源：

• https://datatracker.ietf.org/doc/html/draft-arciszewski-xchacha-03
• https://www.rfc-editor.org/rfc/rfc8439

完整示例代码

import 'package:flutter/cupertino.dart';
import 'package:prefix_encrypt/prefix_encrypt.dart';

void main() {
  // 所有值必须为十六进制

  String aad = "000000000000000000000000"; // 必须至少为1个字符
  String key = 
      "0000000000000000000000000000000000000000000000000000000000000000"; // 密钥必须为64个字符
  String iv = "0000000000000000"; // 必须至少为16个字符
  String constant = "00000000"; // 必须为8个字符
  String hNonce = 
      "000000000000000000000000000000000000000000000000"; // 必须为48个字符
  String plaintextPrefix = "Hello World!😄";
  String plaintextWithoutPrefix = "Hello World!";

  Future<void> aeadXchacha20poly1305prefix() async {
    List encrypt = await AEADxChaCha20poly1305withPrefix.encrypt(
        aad: aad,
        iv: iv,
        key: key,
        constant: constant,
        hNonce: hNonce,
        plaintext: plaintextPrefix);
    String decrypt = await AEADxChaCha20poly1305withPrefix.decrypt(
        aad: aad,
        iv: iv,
        key: key,
        constant: constant,
        hNonce: hNonce,
        ciphertext: encrypt[0],
        savedTag: encrypt[1]);

    debugPrint("$encrypt\n$decrypt");
  }

  Future<void> xChaChaPrefix() async {
    String encrypt = await XChaCha20withPrefix.encrypt(
        key: key, nonce: hNonce, plaintext: plaintextPrefix);
    String decrypt = await XChaCha20withPrefix.decrypt(
        key: key, nonce: hNonce, ciphertext: encrypt);

    debugPrint("$encrypt\n$decrypt");
  }

  Future<void> aeadXchacha20poly1305() async {
    List encrypt = await AEADxChaCha20poly1305.encrypt(
        aad: aad,
        iv: iv,
        key: key,
        constant: constant,
        hNonce: hNonce,
        plaintext: plaintextWithoutPrefix);
    String decrypt = await AEADxChaCha20poly1305.decrypt(
        aad: aad,
        iv: iv,
        key: key,
        constant: constant,
        hNonce: hNonce,
        ciphertext: encrypt[0],
        savedTag: encrypt[1]);

    debugPrint("$encrypt\n$decrypt");
  }

  Future<void> xChaCha20() async {
    String encrypt = await XChaCha20.encrypt(
        key: key, nonce: hNonce, plaintext: plaintextWithoutPrefix);
    String decrypt = 
        await XChaCha20.decrypt(key: key, nonce: hNonce, ciphertext: encrypt);

    debugPrint("$encrypt\n$decrypt");
  }

  aeadXchacha20poly1305prefix();
  xChaChaPrefix();
  aeadXchacha20poly1305();
  xChaCha20();
}