Delphi DLL

Generating Repeatable Random Data for Testing/Debugging

See more PRNG Examples

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

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

...

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

begin
success := False;

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

success := False;

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);

CkPrng_Dispose(fortuna);
CkPrng_Dispose(fortuna2);

end;