How to generate machinekey for web.config?

# Generates a <machineKey> element that can be copied + pasted into a Web.config file.

function Generate-MachineKey {

  [CmdletBinding()]

  param (

    [ValidateSet("AES", "DES", "3DES")]

    [string]$decryptionAlgorithm = 'AES',

    [ValidateSet("MD5", "SHA1", "HMACSHA256", "HMACSHA384", "HMACSHA512")]

    [string]$validationAlgorithm = 'HMACSHA256'

  )

  process {

    function BinaryToHex {

        [CmdLetBinding()]

        param($bytes)

        process {

            $builder = new-object System.Text.StringBuilder

            foreach ($b in $bytes) {

              $builder = $builder.AppendFormat([System.Globalization.CultureInfo]::InvariantCulture, "{0:X2}", $b)

            }

            $builder

        }

    }

    switch ($decryptionAlgorithm) {

      "AES" { $decryptionObject = new-object System.Security.Cryptography.AesCryptoServiceProvider }

      "DES" { $decryptionObject = new-object System.Security.Cryptography.DESCryptoServiceProvider }

      "3DES" { $decryptionObject = new-object System.Security.Cryptography.TripleDESCryptoServiceProvider }

    }

    $decryptionObject.GenerateKey()

    $decryptionKey = BinaryToHex($decryptionObject.Key)

    $decryptionObject.Dispose()

    switch ($validationAlgorithm) {

      "MD5" { $validationObject = new-object System.Security.Cryptography.HMACMD5 }

      "SHA1" { $validationObject = new-object System.Security.Cryptography.HMACSHA1 }

      "HMACSHA256" { $validationObject = new-object System.Security.Cryptography.HMACSHA256 }

      "HMACSHA385" { $validationObject = new-object System.Security.Cryptography.HMACSHA384 }

      "HMACSHA512" { $validationObject = new-object System.Security.Cryptography.HMACSHA512 }

    }

    $validationKey = BinaryToHex($validationObject.Key)

    $validationObject.Dispose()

    [string]::Format([System.Globalization.CultureInfo]::InvariantCulture,

      "<machineKey decryption=`"{0}`" decryptionKey=`"{1}`" validation=`"{2}`" validationKey=`"{3}`" />",

      $decryptionAlgorithm.ToUpperInvariant(), $decryptionKey,

      $validationAlgorithm.ToUpperInvariant(), $validationKey)
  }
}