Generated shell script doesn't output anything

Question

I have the following powershell script from original source. It is used for generating a machine key for validation of the viewstate MAC. However, when I run it in Powershell:

PS C:\Users\Documents> .\Generate-MachineKey.ps1 -decryptionAlgorithm AES -validationAlgorithm SHA1

Nothing is being output, the following is the script. What is the reason that nothing is output.

 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)
  }
}

Note: stackoverflow.com/q/39576902/45375 is closely related, but not quite a duplicate. — mklement0
– mklement0, Commented Mar 26, 2018 at 14:16

maoizm · Accepted Answer · 2018-03-26 15:25:38Z

2

Because by calling script file in your command you actually do not call the function Generate-MachineKey inside the script.

Correct way in your case would be "dot source" the script file and then call the function contained within the script:

. .\Generate-MachineKey.ps1
Generate-MachineKey -decryptionAlgorithm AES -validationAlgorithm SHA1

Please read dot sourcing Powershell scripts for more details and understand the difference between scripts, functions, calling and dot sourcing concepts

edited Mar 26, 2018 at 15:25

answered Mar 26, 2018 at 5:22

maoizm

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Comments

boxdog · Accepted Answer · 2018-03-26 05:24:29Z

1

You are calling the script, but no the function inside. Add a call to your function at the end of the script:

Generate-MachineKey -decryptionAlgorithm AES  -validationAlgorithm SHA1

Alternatively, you can take the code out of the function and just have the 'param' section as the parameters definition for the script instead.

answered Mar 26, 2018 at 5:24

boxdog

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