(Delphi DLL) Generating Repeatable Random Data for Testing/Debugging

Demonstrates how to use the Fortuna PRNG to generate random-looking but repeatable non-random data for the purpose of testing and debugging.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Prng, Global;

...

procedure TForm1.Button1Click(Sender: TObject);
var
chilkatGlob: HCkGlobal;
success: Boolean;
fortuna: HCkPrng;
strRandHex: PWideChar;
strRandBase64: PWideChar;
strRandBase58: PWideChar;
fortuna2: HCkPrng;

begin
// All Chilkat classes can be unlocked at once at the beginning of a program
// by calling UnlockBundle.  It requires a Bundle unlock code.
chilkatGlob := CkGlobal_Create();
success := CkGlobal_UnlockBundle(chilkatGlob,'Anything for 30-day trial.');
if (success <> True) then
  begin
    Memo1.Lines.Add(CkGlobal__lastErrorText(chilkatGlob));
    Exit;
  end;

fortuna := CkPrng_Create();

// Normally an application would seed the PRNG with entropy from
// some real random source.  However, sometimes we want the same
// random sequence of bytes for testing and debugging purposes.
// This a reason why GetEntropy and AddEntropy are two different methods.
// An application could omit the call to GetEntropy, and instead pass
// non-random data to AddEntropy. For example:

// Seed the PRNG with non-entropy, so we get a repeatable sequence.
// Note: AddEntropy can be called any number of times.
success := CkPrng_AddEntropy(fortuna,'01020304','hex');
success := CkPrng_AddEntropy(fortuna,'hello world','ascii');

// Generate some random data:
strRandHex := CkPrng__genRandom(fortuna,16,'hex');
strRandBase64 := CkPrng__genRandom(fortuna,22,'base64');
strRandBase58 := CkPrng__genRandom(fortuna,32,'base58');

Memo1.Lines.Add('hex random bytes: ' + strRandHex);
Memo1.Lines.Add('base64 random bytes: ' + strRandBase64);
Memo1.Lines.Add('base58 random bytes: ' + strRandBase58);

// Try it again with a different object to verify that the same results are obtained:
fortuna2 := CkPrng_Create();

success := CkPrng_AddEntropy(fortuna2,'01020304','hex');
success := CkPrng_AddEntropy(fortuna2,'hello world','ascii');

strRandHex := CkPrng__genRandom(fortuna2,16,'hex');
strRandBase64 := CkPrng__genRandom(fortuna2,22,'base64');
strRandBase58 := CkPrng__genRandom(fortuna2,32,'base58');

Memo1.Lines.Add('hex random bytes: ' + strRandHex);
Memo1.Lines.Add('base64 random bytes: ' + strRandBase64);
Memo1.Lines.Add('base58 random bytes: ' + strRandBase58);

CkGlobal_Dispose(chilkatGlob);
CkPrng_Dispose(fortuna);
CkPrng_Dispose(fortuna2);

end;