New-EncryptedCredentialFile.ps1

<#

Author: I. Strachan
Version: 1.0
Version History:

Purpose: Create an encrypted password file and saves the password as
         a Credential object
#>
function New-EncryptedCredentialFile {
    [CmdletBinding()]
    param(
        [String]$ThumbPrint = '0460483ADEF613D3B1781FAE393DF2AEAE1060ED',

        [String]$PasswordFile = 'C:\scripts\source\txt\Password.txt',

        [ValidateRange(20, 128)] 
        [Int]$PasswordLength = 100
    )

    #Load "System.Web" assembly in PowerShell console 
    $null = [Reflection.Assembly]::LoadWithPartialName("System.Web")

    #Calling Generated Password Method 
    $ClearPassword = [System.Web.Security.Membership]::GeneratePassword($PasswordLength, 0)
    $ClearPassword |
        Protect-CmsMessage -OutFile $PasswordFile -To $ThumbPrint 

    #return Credential for encryption
    $Credential = [PSCredential]::new($ThumbPrint, $($ClearPassword | ConvertTo-SecureString -AsPlainText -Force))
    $Credential
}

$Cred = New-EncryptedCredentialFile -ThumbPrint '0A5A254C42D710E2C0B1BC77B142FAEC7EA7B93B' 

#Region Compress and password protect 7zip file
$param7Zip = @{
    Path            = 'c:\scripts\export\dsa\20062017'
    ArchiveFileName = 'pshirwin-20062017.7zp'
    Format          = 'SevenZip'
    SecurePassword  = $Cred.Password
}

Compress-7Zip @param7Zip
#Endregion

#Region Expand 7Zip protected password file
#Retrieve exported Credentials
$thumbPrint = '0A5A254C42D710E2C0B1BC77B142FAEC7EA7B93B'

$passwd = Unprotect-CmsMessage -LiteralPath 'C:\scripts\sources\txt\Password.txt' -To $thumbPrint | 
    ConvertTo-SecureString -AsPlainText -Force

$Creds = [PSCredential]::new($thumbPrint, $passwd)
    
Expand-7Zip -ArchiveFileName 'pshirwin-20062017.7zp' -TargetPath .\temp\pshirwin-20062017 -SecurePassword $Creds.Password
#Endregion