Generate Psuedo-Random Data using ARC4 as a PRNG

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.

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Dim crypt As New Chilkat.Crypt2()

Dim success As Boolean
success = crypt.UnlockComponent("Anything for 30-day trial")
If (success <> true) 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 True to initialize the ARC4 PRNG with the key.
crypt.FirstChunk = true
crypt.LastChunk = false

Dim encryptedText As String
encryptedText = crypt.EncryptStringENC(strData)
TextBox1.Text = TextBox1.Text & encryptedText & vbCrLf
TextBox1.Refresh()

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

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)
    TextBox1.Text = TextBox1.Text & encryptedText & vbCrLf
    TextBox1.Refresh()
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