test powershell rc4

posh-rc4.ps1

function RC4 {
    param([Byte[]]$buffer)

	$key = ([system.Text.Encoding]::UTF8).GetBytes("abcdefghjikjlmnopqrstuvwxyz")

    $s = New-Object Byte[] 256;
    $k = New-Object Byte[] 256;

    for ($i = 0; $i -lt 256; $i++)
    {
        $s[$i] = [Byte]$i;
        $k[$i] = $key[$i % $key.Length];
    }

    $j = 0;
    for ($i = 0; $i -lt 256; $i++)
    {
        $j = ($j + $s[$i] + $k[$i]) % 256;
        $temp = $s[$i];
        $s[$i] = $s[$j];
        $s[$j] = $temp;
    }

    $i = $j = 0;
    for ($x = 0; $x -lt $buffer.Length; $x++)
    {
        $i = ($i + 1) % 256;
        $j = ($j + $s[$i]) % 256;
        $temp = $s[$i];
        $s[$i] = $s[$j];
        $s[$j] = $temp;
        [int]$t = ($s[$i] + $s[$j]) % 256;
        $buffer[$x] = $buffer[$x] -bxor $s[$t];
    }

    $buffer
}

RC4(@(1..10))

$cleartext = @()
$x = 123
1 .. 10000 | % { $x = (43*$x + 23) % 256;  $cleartext += $x }
Get-FileHash -InputStream ([System.IO.MemoryStream]::New($cleartext))
$ciphertext = RC4($cleartext)
Get-FileHash -InputStream ([System.IO.MemoryStream]::New(($ciphertext)))