Test_SynCrypto_AES_GUI.dpr

program Test_SynCrypto_AES_GUI;

uses
  Vcl.Forms,
  uMainForm in 'uMainForm.pas' {MainForm};

{$R *.res}

begin
  Application.Initialize;
  Application.MainFormOnTaskbar := True;
  Application.CreateForm(TMainForm, MainForm);
  Application.Run;
end.

uMainForm.dfm

object MainForm: TMainForm
  Left = 0
  Top = 0
  Caption = 'MainForm'
  ClientHeight = 603
  ClientWidth = 635
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  PixelsPerInch = 96
  TextHeight = 13
  object btnEncrypt: TButton
    Left = 64
    Top = 376
    Width = 153
    Height = 113
    Caption = 'btnEncrypt'
    TabOrder = 0
    OnClick = btnEncryptClick
  end
  object btnDecrypt: TButton
    Left = 312
    Top = 376
    Width = 193
    Height = 113
    Caption = 'btnDecrypt'
    TabOrder = 1
    OnClick = btnDecryptClick
  end
  object mmoPlain: TMemo
    Left = 48
    Top = 64
    Width = 217
    Height = 273
    Lines.Strings = (
      #27979#35797#26126#25991#31532'1'#34892
      #27979#35797#26126#25991#31532'2'#34892)
    TabOrder = 2
  end
  object mmoCipher: TMemo
    Left = 271
    Top = 64
    Width = 290
    Height = 273
    TabOrder = 3
  end
end

uMainForm.pas

unit uMainForm;

interface

uses
  Windows, Messages,
  SysUtils, Variants, Classes,
  Graphics, Controls, Forms, Dialogs, StdCtrls;

type
  TMainForm = class(TForm)
    btnEncrypt: TButton;
    btnDecrypt: TButton;
    mmoPlain: TMemo;
    mmoCipher: TMemo;
    procedure btnEncryptClick(Sender: TObject);
    procedure btnDecryptClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  MainForm: TMainForm;

implementation

{$R *.dfm}
uses
  SynCommons, SynLog, SynCrypto;

const
  TEST_KEY: string = 'TEST_KEY';

procedure TMainForm.btnEncryptClick(Sender: TObject);
var
  Key: TSHA256Digest;
  plain, cipher: RawByteString;
begin
  SHA256Weak(TEST_KEY, Key);
  plain := StringToUTF8(mmoPlain.Text);
//  mmoPlain.Text := UTF8ToString(plain);
//  mmoPlain.Text := UTF8ToString(AnyAnsiToUTF8(plain));
//  Exit;
  cipher := SynCrypto.AES(Key, 256, plain, true);
  mmoCipher.Text :=  UTF8ToString(BinToBase64(cipher));
end;

type
  ChineseString = type Ansistring(936); // https://stackoverflow.com/questions/7222615/how-can-i-convert-string-encoded-with-windows-codepage-1251-to-a-unicode-string

procedure TMainForm.btnDecryptClick(Sender: TObject);
var
  Key: TSHA256Digest;
  plain, cipher: RawByteString;
  ChineseStr: ChineseString;
begin
  SHA256Weak(TEST_KEY, Key);
  cipher := Base64ToBin(StringToUTF8(mmoCipher.Text));
  plain := SynCrypto.AES(Key, 256, cipher, false);

  mmoPlain.Text := UTF8ToString(AnyAnsiToUTF8(plain)); // Does not work
//  mmoPlain.Text := UTF8ToString(CurrentAnsiConvert.AnsiToUTF8(plain)); // Does not work
//  mmoPlain.Text := UTF8ToUnicodeString(CurrentAnsiConvert.AnsiToUTF8(plain)); // Does not work

//  ChineseStr := UTF8ToString(AnyAnsiToUTF8(plain)); // Does not work
//  mmoPlain.Text := ChineseStr;
end;

end.