Powershell data read from file contains dollar sign $ - powershell

Question

I have a powershell script that is reading a password from a file, the password has been 'secured' using a generated AES Key. There are three files used in the process
AES Key File Generation:
$KeyFile = "\\server\path\AES.key"
$Key = New-Object Byte[] 16
[Security.Cryptography.RNGCryptoServiceProvider]::Create().GetBytes($Key)
$Key | out-file $KeyFile
Password File Generation:
$PasswordFile = "\\server\path\Password.txt"
$KeyFile = "\\server\path\AES.key"
$Key = Get-Content $KeyFile
$Password = "Sy$tem#dmin" | ConvertTo-SecureString -AsPlainText -Force
$Password | ConvertFrom-SecureString -key $Key | Out-File $PasswordFile
Script That Grabs Password File and Converts back to Plain Text:
$User = "myuser"
$PasswordFile = "\\server\path\Password.txt"
$KeyFile = "\\server\path\AES.key"
$key = Get-Content $KeyFile
$MyCredential = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList $User, (Get-Content $PasswordFile | ConvertTo-SecureString -Key $key)
$PlainPassword2 = $MyCredential.GetNetworkCredential().Password
$PlainPassword2
The conversion back to plain text is really being done just so we can verify that the data is the same as what was initially created.
When we display the data contained in $PlainPassword2 instead of seeing Sy$tem#dmin as is expected, we are seeing Sy#dmin.
What can we do to correct this?

Answer 1

You are using double-quotes when converting the original password string:
$Password = "Sy$tem#dmin" | ConvertTo-SecureString -AsPlainText -Force
Since " allow for string interpolation, the parser tries to expand $tem, which, since it probably doesn't exist results in an empty string, thus you end up with the string you see in your output.
Use single-quotes instead:
$Password = 'Sy$tem#dmin' | ConvertTo-SecureString -AsPlainText -Force