#
# Encrypt and Decrypt using Rijndael 256bit 
#

# change the following two secret phrases
$salt = "secretSentence"
$init = "anotherSecretSentence"

# supply a strong password
$password = "mySecretPassword!"

#
# check bottom of the script for Samples
#



function Encrypt-String([string]$String)
{
    $rijndaelCSP = New-Object System.Security.Cryptography.RijndaelManaged
    $pass = [Text.Encoding]::UTF8.GetBytes($password)
    $salt = [Text.Encoding]::UTF8.GetBytes($salt)
 
    $rijndaelCSP.Key = (New-Object Security.Cryptography.PasswordDeriveBytes $pass, $salt, "SHA1", 5).GetBytes(32) #256/8
    $rijndaelCSP.IV = (New-Object Security.Cryptography.SHA1Managed).ComputeHash( [Text.Encoding]::UTF8.GetBytes($init) )[0..15]
   
	$encryptor = $rijndaelCSP.CreateEncryptor()

	$memoryStream = New-Object System.IO.MemoryStream
	$encryptStream = New-Object Security.Cryptography.CryptoStream $memoryStream, $encryptor, "Write"

	$streamWriter = New-Object System.IO.StreamWriter $encryptStream
	$streamWriter.Write($String)
	$streamWriter.Close()

	$encryptStream.Close()
	$memoryStream.Close()
	$rijndaelCSP.Clear()
	[byte[]]$result = $memoryStream.ToArray()
	[Convert]::ToBase64String($result)
}
	 
function Decrypt-String([string]$Encrypted)
{
	$Encrypted = [Convert]::FromBase64String($Encrypted)

	$rijndaelCSP = New-Object System.Security.Cryptography.RijndaelManaged
	$pass = [System.Text.Encoding]::UTF8.GetBytes($password)
	$salt = [System.Text.Encoding]::UTF8.GetBytes($salt)
	 
	$rijndaelCSP.Key = (New-Object Security.Cryptography.PasswordDeriveBytes $pass, $salt, "SHA1", 5).GetBytes(32) #256/8
	$rijndaelCSP.IV = (New-Object Security.Cryptography.SHA1Managed).ComputeHash( [Text.Encoding]::UTF8.GetBytes($init) )[0..15]
	 
	$decryptor = $rijndaelCSP.CreateDecryptor()

	$memoryStream = New-Object IO.MemoryStream @(,$Encrypted)
	$decryptStream = New-Object Security.Cryptography.CryptoStream $memoryStream, $decryptor, "Read"

	$streamReader = New-Object System.IO.StreamReader $decryptStream
	Write-Output $streamReader.ReadToEnd()
	$streamReader.Close()

	$decryptStream.Close()
	$memoryStream.Close()
	$rijndaelCSP.Clear()
}


function Encrypt-File([string]$fileName, [string]$encryptedFile)
{
    if($encryptedFile -eq $null -or $encryptedFile -eq "")
    {
        $encryptedFile = $fileName
    }

    $rijndaelCSP = New-Object System.Security.Cryptography.RijndaelManaged
    $pass = [Text.Encoding]::UTF8.GetBytes($password)
    $salt = [Text.Encoding]::UTF8.GetBytes($salt)
 
    $rijndaelCSP.Key = (New-Object Security.Cryptography.PasswordDeriveBytes $pass, $salt, "SHA1", 5).GetBytes(32) #256/8
    $rijndaelCSP.IV = (New-Object Security.Cryptography.SHA1Managed).ComputeHash( [Text.Encoding]::UTF8.GetBytes($init) )[0..15]
   
	$encryptor = $rijndaelCSP.CreateEncryptor()

    $inputFileStream = New-Object System.IO.FileStream($fileName, [System.IO.FileMode]::Open, [System.IO.FileAccess]::Read)
    [int]$dataLen = $inputFileStream.Length
    [byte[]]$inputFileData = New-Object byte[] $dataLen
    [void]$inputFileStream.Read($inputFileData, 0, $dataLen)
    $inputFileStream.Close()

    $outputFileStream = New-Object System.IO.FileStream($encryptedFile, [System.IO.FileMode]::Create, [System.IO.FileAccess]::Write)
	
    $encryptStream = New-Object Security.Cryptography.CryptoStream $outputFileStream, $encryptor, "Write"
    $encryptStream.Write($inputFileData, 0, $dataLen)
	$encryptStream.Close()

    $outputFileStream.Close()
	$rijndaelCSP.Clear()
}
	 
function Decrypt-File([string]$encryptedFile, [string]$decryptedFile)
{
    if($decryptedFile -eq $null -or $decryptedFile -eq "")
    {
        $decryptedFile = $encryptedFile
    }

	$rijndaelCSP = New-Object System.Security.Cryptography.RijndaelManaged
	$pass = [System.Text.Encoding]::UTF8.GetBytes($password)
	$salt = [System.Text.Encoding]::UTF8.GetBytes($salt)
	 
	$rijndaelCSP.Key = (New-Object Security.Cryptography.PasswordDeriveBytes $pass, $salt, "SHA1", 5).GetBytes(32) #256/8
	$rijndaelCSP.IV = (New-Object Security.Cryptography.SHA1Managed).ComputeHash( [Text.Encoding]::UTF8.GetBytes($init) )[0..15]
	 
	$decryptor = $rijndaelCSP.CreateDecryptor()

    $inputFileStream = New-Object System.IO.FileStream($encryptedFile, [System.IO.FileMode]::Open, [System.IO.FileAccess]::Read)
	$decryptStream = New-Object Security.Cryptography.CryptoStream $inputFileStream, $decryptor, "Read"
    
    [int]$dataLen = $inputFileStream.Length
    [byte[]]$inputFileData = New-Object byte[] $dataLen
    [int]$decryptLength = $decryptStream.Read($inputFileData, 0, $dataLen)
    $decryptStream.Close()
    $inputFileStream.Close()

    $outputFileStream = New-Object System.IO.FileStream($decryptedFile, [System.IO.FileMode]::Create, [System.IO.FileAccess]::Write)
    $outputFileStream.Write($inputFileData, 0, $decryptLength)
    $outputFileStream.Close()

	$rijndaelCSP.Clear()
}


#
# Samples
#
# Note: change the file/folder names in the samples
#

# encrypt text
Encrypt-String "Hello"

# decrypt text
Decrypt-String "Zyy9onHG3BZewD7dMjqd8g=="

# encrypt single file
Encrypt-File "D:\test\z.zip" "D:\test\z1.zip"

# decrypt single file
Decrypt-File "D:\test\z1.zip" "D:\test\z2.zip"

# encrypt folder content
Get-ChildItem D:\test\ | % { Encrypt-File $_.FullName ($_.FullName + ".encrypted") }

# encrypt folder content, override existing file
Get-ChildItem D:\test\ | % { Encrypt-File $_.FullName }

# decrypt folder content
Get-ChildItem D:\test\ | % { Decrypt-File $_.FullName }
Get-ChildItem D:\test\ | % { Decrypt-File ($_.FullName + ".encrypted") }