PowerShell trouble with base64 encoding

Question

I need to turn an array of comma-seperated values (a .csv) into a bit of JSON that looks like this:

"traits": {
  "file": {
    "content": "R0lGODlhABAQAIAAAAAAAP///yH7BAEAAAAALAAAAAAEAABAAAIBRAA5",
    "file_name": "test.png"
  }
}

I am using the following:

$traits = New-Object PSObject
$file = New-Object PSObject
$file | Add-Member -Type NoteProperty -Name file_name -Value "file.csv"
$file | Add-Member -Type NoteProperty -Name content -Value $([Convert]::ToBase64String([System.Text.Encoding]::Unicode.GetBytes(($domain.GPOs | ConvertTo-Csv))))
$traits | Add-Member -Type NoteProperty -Name group-policies -Value $file

It seems that the content of "content" is incorrectly encoded. To troubleshoot, I copied the content to www.freeformatter.com/base64-encoder.html and found that they don't match.

What am I missing?

Edit: Here is the content of the .csv. This is what I pasted into https://www.freeformatter.com/base64-encoder.html#ad-output:

#TYPE Selected.System.Xml.XmlElement
"Name","GUID","Linked To","Computer Settings","User Settings"
"Autodiscover - Shared Namespace","249b1923-523a-40b6-9180-cc2727414b9b","@{OU Name=servers; OU Path=domain.local/location/servers; Enabled=true; Enforced=false}","@{Enabled=true; Settings=}","@{Enabled=true; Settings=}"

Powershell outputs this:

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

The website spits out:

I1RZUEUgU2VsZWN0ZWQuU3lzdGVtLlhtbC5YbWxFbGVtZW50DQoiTmFtZSIsIkdVSUQiLCJMaW5rZWQgVG8iLCJDb21wdXRlciBTZXR0aW5ncyIsIlVzZXIgU2V0dGluZ3MiDQoiQXV0b2Rpc2NvdmVyIC0gU2hhcmVkIE5hbWVzcGFjZSIsIjI0OWIxOTIzLTUyM2EtNDBiNi05MTgwLWNjMjcyNzQxNGI5YiIsIkB7T1UgTmFtZT1zZXJ2ZXJzOyBPVSBQYXRoPWRvbWFpbi5sb2NhbC9sb2NhdGlvbi9zZXJ2ZXJzOyBFbmFibGVkPXRydWU7IEVuZm9yY2VkPWZhbHNlfSIsIkB7RW5hYmxlZD10cnVlOyBTZXR0aW5ncz19IiwiQHtFbmFibGVkPXRydWU7IFNldHRpbmdzPX0i

Answer 1

There are three (potential) problems:

• Character encoding:

  • www.freeformatter.com bases the Base64 encoding on the input string's UTF-8 encoding.
  • Your PowerShell code uses UTF-16LE ("Unicode") encoding as the basis; use [System.Text.Encoding]::UTF8.GetBytes() instead, if you want UTF-8.

• Style of newlines (line endings)

  • Newlines in text pasted at www.freeformatter.com are quietly converted to Windows-style CRLF newlines, whereas your input may have Unix-style LF-only newlines.

• Newlines getting lost:

  • You're passing the output from ConvertTo-Csv, which is an array of strings to [System.Text.Encoding]::Unicode.GetBytes(), which expects a single string. In the process PowerShell stringifies the array, which means that its elements are joined with a space as the separator, so the original newlines are replaced with spaces, resulting in different encoded output.
  • Therefore, instead of ($domain.GPOs | ConvertTo-Csv), use ($domain.GPOs | ConvertTo-Csv) -join [Environment]::NewLine (which uses the platform-appropriate newline sequence; alternatively, use "`n" or "`r`n" explicitly; also, you may want to append a trailing newline).