[Casimiro Notevi]

He hecho una prueba:

Código simple "chapuzero" :

Código Delphi [-]
unit uMain;

interface

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

type
  TForm19 = class(TForm)
    ed1: TEdit;
    bt1: TButton;
    ed2: TEdit;
    ed3: TEdit;
    bt2: TButton;
    procedure bt1Click(Sender: TObject);
    procedure bt2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form19: TForm19;

implementation

uses
  uBase58;

{$R *.dfm}

procedure TForm19.bt1Click(Sender: TObject);
var
  cValor : UInt64;
begin
  cValor := StrToInt64(ed1.Text);
  ed2.Text := uBase58.Base58Encode( cValor );
end;

procedure TForm19.bt2Click(Sender: TObject);
var
  cValor : UInt64;
  i64 : Int64;
begin
  uBase58.Base58Decode(ed2.Text,cValor);
  i64 := cValor;   
  ed3.Text := IntToStr(i64);
end;

end.