Generate Psuedo-Random Data using ARC4 as a PRNG

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This example demonstrates how to use the ARC4 stream encryption algorithm as a pseudo-random number generator (PRNG). This example generates the random data as hex encoded strings. The EncryptStringENC method can be replaced with EncryptBytes to generate random bytes. Note: This example uses new features available in the pre-release, or any official new version released after 17-October-2007.

Dim crypt As New ChilkatCrypt2

Dim success As Long
success = crypt.UnlockComponent("Anything for 30-day trial")
If (success <> 1) Then
    MsgBox "Crypt component unlock failed"
    Exit Sub
End If

crypt.CryptAlgorithm = "arc4"
crypt.KeyLength = 128

crypt.SetEncodedKey "000102030405060708090A0B0C0D0E0F","hex"

crypt.EncodingMode = "hex"

'  We will repeatedly feed these 8-bytes of data to
'  the ARC4 stream encryptor to generate our pseudo-random
'  sequence.
Dim strData As String
strData = "012345678"

'  Set FirstChunk to 1 to initialize the ARC4 PRNG with the key.
crypt.FirstChunk = 1
crypt.LastChunk = 0

Dim encryptedText As String
encryptedText = crypt.EncryptStringENC(strData)
Text1.Text = Text1.Text & encryptedText & vbCrLf
Text1.Refresh

'  Set FirstChunk to 0 to continue encrypting
'  without re-initializing the ARC4 PRNG
crypt.FirstChunk = 0

Dim i As Long
For i = 1 To 15
    '  Repeatedly encrypting the same 8 bytes of data
    '  produces then pseudo-random sequence.
    encryptedText = crypt.EncryptStringENC(strData)
    Text1.Text = Text1.Text & encryptedText & vbCrLf
    Text1.Refresh
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