Powershell module to do machine-specific encryption.

MachineEncryption.psm1

Add-Type -AssemblyName "System.Security"

function ConvertTo-EncryptedString{
    [cmdletbinding()]
    [OutputType([string])]
    param(
        [parameter(Mandatory=$true, ValueFromPipeline=$true)]
        [ValidateNotNull()]
        [string]$stringToEncrypt)
    Process{
        [System.Reflection.Assembly]::LoadWithPartialName("System.Security")
        $bytesToEncrypt = [System.Text.Encoding]::UTF8.GetBytes($stringToEncrypt)
        $encryptedBytes = [System.Security.Cryptography.ProtectedData]::Protect(
            $bytesToEncrypt,
            $null,
            [System.Security.Cryptography.DataProtectionScope]::LocalMachine)
        [System.Convert]::ToBase64String($encryptedBytes)
    }
}

function ConvertTo-DecryptedString{
    [cmdletbinding()]
    [OutputType([string])]
    param(
        [parameter(Mandatory=$true, ValueFromPipeline=$true)]
        [ValidateNotNull()]
        [string]$stringToDecrypt)
    Process{
        $bytesToDecrypt = [System.Convert]::FromBase64String($stringToDecrypt)
        $decryptedBytes = [System.Security.Cryptography.ProtectedData]::Unprotect(
            $bytesToDecrypt, 
            $null, 
            [System.Security.Cryptography.DataProtectionScope]::LocalMachine)
        [System.Text.Encoding]::UTF8.GetString($decryptedBytes)
    }
}

Export-ModuleMember -Function 'ConvertTo-*'