##############################################################################
#.SYNOPSIS
#   Demonstrate how to work with secure string objects.
#.NOTES
#    Date: 24.Sep.2013
# Version: 2.0
#   Notes: Credit for deobfuscation function goes to MoW, The PowerShell Guy:
#          http://thepowershellguy.com/blogs/posh/archive/2007/02/21/scripting-games-2007-advanced-powershell-event-7.aspx
#   Legal: 0BSD
##############################################################################


# Dialog box appears to ask for a username and password:
$cred = get-credential   


# The username can be displayed, but the password cannot:
$cred.username 
$cred.password 


# Unless you have PoSh 3.0+:
$cred.GetNetworkCredential().Password


# This function will return the plaintext of a "secure" string from either
# a secure string object or from a credential object's password property.
# It works on PoSh 1.0 and later:
Function Reveal-SecureString ($SecureObject)
{
    if ($SecureObject.GetType().FullName -eq "System.Management.Automation.PSCredential")
    { $SecureObject = $SecureObject.Password }

    $bstr = [System.Runtime.InteropServices.Marshal]::SecureStringToBSTR($SecureObject)
    [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($bstr)
}


# For example:
reveal-securestring -secureobject $cred




# Demonstrates a non-interactive way to convert a plaintext string into a secure string:
Function New-SecureString ($PlainText)
{
    $SecureString = New-Object -TypeName System.Security.SecureString
    $PlainText.ToCharArray() | ForEach-Object { $SecureString.AppendChar( $_ ) } 
    $SecureString
}




# Create a credential object for use with Start-Process, Invoke-Command and
# many other cmdlets (see 'get-command -ParameterName Credential' for the full list):
Function New-Credential ($UserName, $Password)
{
    $SecureString = New-Object -TypeName System.Security.SecureString
    $Password.ToCharArray() | ForEach-Object { $SecureString.AppendChar( $_ ) } 
    New-Object -Typename System.Management.Automation.PSCredential -Argumentlist $UserName,$SecureString
}



## Here is an example to run a process as the guest account with a password of "sekrit":
# Start-Process -FilePath "cmd.exe" -ArgumentList "/k" -Credential $(new-credential -username "guest" -password "sekrit")



##########################################################
#  Secure strings can be encrypted with a raw AES key
#  and used on another computer.
##########################################################

# Get 32 bytes for a 256-bit AES key with DOUBLE randomness, for free!  ;-)
[Byte[]] $Key = 1..100 | ForEach { Get-Random -Minimum 0 -Maximum 255 } | Get-Random -Count 32

# Save $Key as a binary file:
Set-Content -NoNewline -Encoding Byte -Value $Key -Path "$Env:TEMP\TheKey.bin"

# Create a secure string you need on another computer, perhaps with Get-Credential:
$SecureString = 'P@ssword' | ConvertTo-SecureString -AsPlainText -Force

# Encrypt and save that secure string to a base64 file, send to other computer:
$SecureString | ConvertFrom-SecureString -Key $Key | Out-File -FilePath "$Env:TEMP\TheEncryptedPassword.txt" 

# On the other computer, get the key somehow, preferably not involving the hard drive though:
$KeyFromFile = Get-Content -Encoding Byte -Path "$Env:TEMP\TheKey.bin" 

# On the other computer, decrypt the password to recreate the needed secure string:
$PasswordFromFile = New-Object -TypeName System.Management.Automation.PSCredential -ArgumentList @('TESTING\Administrator', $(Get-Content "$Env:TEMP\TheEncryptedPassword.txt" | ConvertTo-SecureString -Key $KeyFromFile))