B4X

Generating Repeatable Random Data for Testing/Debugging

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Demonstrates how to use the Fortuna PRNG to generate random-looking but repeatable non-random data for the purpose of testing and debugging. B4X

Dim success As Boolean = False

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

success = False

Dim fortuna As ChilkatPrng
fortuna.Initialize

'  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 = fortuna.AddEntropy("01020304", "hex")
success = fortuna.AddEntropy("hello world", "ascii")

'  Generate some random data:
Dim strRandHex As String = fortuna.GenRandom(16, "hex")
Dim strRandBase64 As String = fortuna.GenRandom(22, "base64")
Dim strRandBase58 As String = fortuna.GenRandom(32, "base58")

Log("hex random bytes: " & strRandHex)
Log("base64 random bytes: " & strRandBase64)
Log("base58 random bytes: " & strRandBase58)

'  Try it again with a different object to verify that the same results are obtained:
Dim fortuna2 As ChilkatPrng
fortuna2.Initialize

success = fortuna2.AddEntropy("01020304", "hex")
success = fortuna2.AddEntropy("hello world", "ascii")

strRandHex = fortuna2.GenRandom(16, "hex")
strRandBase64 = fortuna2.GenRandom(22, "base64")
strRandBase58 = fortuna2.GenRandom(32, "base58")

Log("hex random bytes: " & strRandHex)
Log("base64 random bytes: " & strRandBase64)
Log("base58 random bytes: " & strRandBase58)