(Excel) 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.

Download Excel Class Modules Chilkat Excel Class Modules

' All Chilkat classes can be unlocked at once at the beginning of a program
' by calling UnlockBundle.  It requires a Bundle unlock code.
Dim chilkatGlob As Chilkat.CkGlobal
Set chilkatGlob = Chilkat.NewCkGlobal

success = chilkatGlob.UnlockBundle("Anything for 30-day trial.")
If (success <> True) Then
    Debug.Print chilkatGlob.LastErrorText
    Exit Sub
End If

Dim fortuna As Chilkat.Prng
Set fortuna = Chilkat.NewPrng

' 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:

strRandHex = fortuna.GenRandom(16,"hex")

strRandBase64 = fortuna.GenRandom(22,"base64")

strRandBase58 = fortuna.GenRandom(32,"base58")

Debug.Print "hex random bytes: "; strRandHex
Debug.Print "base64 random bytes: "; strRandBase64
Debug.Print "base58 random bytes: "; strRandBase58

' Try it again with a different object to verify that the same results are obtained:
Dim fortuna2 As Chilkat.Prng
Set fortuna2 = Chilkat.NewPrng

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")

Debug.Print "hex random bytes: "; strRandHex
Debug.Print "base64 random bytes: "; strRandBase64
Debug.Print "base58 random bytes: "; strRandBase58