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.

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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