I\'m working in PowerShell and I have code that successfully converts a user entered password into plain text:
$SecurePassword = Read-Host -AsSecureString \
You may also use PSCredential.GetNetworkCredential() :
$SecurePassword = Get-Content C:\Users\tmarsh\Documents\securePassword.txt | ConvertTo-SecureString $UnsecurePassword = (New-Object PSCredential "user",$SecurePassword).GetNetworkCredential().Password