C

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. C

#include <C_CkPrng.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPrng fortuna;
    const char *strRandHex;
    const char *strRandBase64;
    const char *strRandBase58;
    HCkPrng fortuna2;

    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");

    printf("hex random bytes: %s\n",strRandHex);
    printf("base64 random bytes: %s\n",strRandBase64);
    printf("base58 random bytes: %s\n",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");

    printf("hex random bytes: %s\n",strRandHex);
    printf("base64 random bytes: %s\n",strRandBase64);
    printf("base58 random bytes: %s\n",strRandBase58);


    CkPrng_Dispose(fortuna);
    CkPrng_Dispose(fortuna2);

    }