Powershell 之加解密

285572001

#################　　
# Powershell Allows The Loading of .NET Assemblies
　　
# Load the Security assembly to use with this script
　　
#################
　　
[Reflection.Assembly]::LoadWithPartialName("System.Security")
　　
#################
　　
# This function is to Encrypt A String.
　　
# $string is the string to encrypt, $passphrase is a second security "password" that has to be passed to decrypt.
　　
# $salt is used during the generation of the crypto password to prevent password guessing.
　　
# $init is used to compute the crypto hash -- a checksum of the encryption
　　
#################
　　
function Encrypt-String($String, $Passphrase, $salt="SaltCrypto", $init="IV_Password", [switch]$arrayOutput)
　　
{
　　
    # Create a COM Object for RijndaelManaged Cryptography
　　
    $r = new-Object System.Security.Cryptography.RijndaelManaged
　　
    # Convert the Passphrase to UTF8 Bytes
　　
    $pass = [Text.Encoding]::UTF8.GetBytes($Passphrase)
　　
    # Convert the Salt to UTF Bytes
　　
    $salt = [Text.Encoding]::UTF8.GetBytes($salt)
　　

　　
    # Create the Encryption Key using the passphrase, salt and SHA1 algorithm at 256 bits
　　
    $r.Key = (new-Object Security.Cryptography.PasswordDeriveBytes $pass, $salt, "SHA1", 5).GetBytes(32) #256/8
　　
    # Create the Intersecting Vector Cryptology Hash with the init
　　
    $r.IV = (new-Object Security.Cryptography.SHA1Managed).ComputeHash( [Text.Encoding]::UTF8.GetBytes($init) )[0..15]
　　

　　
    # Starts the New Encryption using the Key and IV
　　
    $c = $r.CreateEncryptor()
　　
    # Creates a MemoryStream to do the encryption in
　　
    $ms = new-Object IO.MemoryStream
　　
    # Creates the new Cryptology Stream --> Outputs to $MS or Memory Stream
　　
    $cs = new-Object Security.Cryptography.CryptoStream $ms,$c,"Write"
　　
    # Starts the new Cryptology Stream
　　
    $sw = new-Object IO.StreamWriter $cs
　　
    # Writes the string in the Cryptology Stream
　　
    $sw.Write($String)
　　
    # Stops the stream writer
　　
    $sw.Close()
　　
    # Stops the Cryptology Stream
　　
    $cs.Close()
　　
    # Stops writing to Memory
　　
    $ms.Close()
　　
    # Clears the IV and HASH from memory to prevent memory read attacks
　　
    $r.Clear()
　　
    # Takes the MemoryStream and puts it to an array
　　
    [byte[]]$result = $ms.ToArray()
　　
    # Converts the array from Base 64 to a string and returns
　　
    return [Convert]::ToBase64String($result)
　　
}
　　

　　

　　
function Decrypt-String($Encrypted, $Passphrase, $salt="SaltCrypto", $init="IV_Password")
　　
{
　　
    # If the value in the Encrypted is a string, convert it to Base64
　　
    if($Encrypted -is [string]){
　　
        $Encrypted = [Convert]::FromBase64String($Encrypted)
　　
    }
　　

　　
    # Create a COM Object for RijndaelManaged Cryptography
　　
    $r = new-Object System.Security.Cryptography.RijndaelManaged
　　
    # Convert the Passphrase to UTF8 Bytes
　　
    $pass = [Text.Encoding]::UTF8.GetBytes($Passphrase)
　　
    # Convert the Salt to UTF Bytes
　　
    $salt = [Text.Encoding]::UTF8.GetBytes($salt)
　　

　　
    # Create the Encryption Key using the passphrase, salt and SHA1 algorithm at 256 bits
　　
    $r.Key = (new-Object Security.Cryptography.PasswordDeriveBytes $pass, $salt, "SHA1", 5).GetBytes(32) #256/8
　　
    # Create the Intersecting Vector Cryptology Hash with the init
　　
    $r.IV = (new-Object Security.Cryptography.SHA1Managed).ComputeHash( [Text.Encoding]::UTF8.GetBytes($init) )[0..15]
　　

　　
    # Create a new Decryptor
　　
    $d = $r.CreateDecryptor()
　　
    # Create a New memory stream with the encrypted value.
　　
    $ms = new-Object IO.MemoryStream @(,$Encrypted)
　　
    # Read the new memory stream and read it in the cryptology stream
　　
    $cs = new-Object Security.Cryptography.CryptoStream $ms,$d,"Read"
　　
    # Read the new decrypted stream
　　
    $sr = new-Object IO.StreamReader $cs
　　
    # Return from the function the stream
　　
    Write-Output $sr.ReadToEnd()
　　
    # Stops the stream
　　
    $sr.Close()
　　
    # Stops the crypology stream
　　
    $cs.Close()
　　
    # Stops the memory stream
　　
    $ms.Close()
　　
    # Clears the RijndaelManaged Cryptology IV and Key
　　
    $r.Clear()
　　
}
　　
# This clears the screen of the output from the loading of the assembly. cls
　　
# $me will never = 1, so It will run indefinately $me = 0
　　
    write-host "To End This Application, Close the Window"
　　
    Write-host ""
　　
do
　　
{
　　
    # Prompt the user for the password
　　
    $string = read-host "Please Enter User Password"
　　
    # Encrypt the string and store it into the $encrypted variable
　　
    $encrypted = Encrypt-String $string "MyStrongPassword"
　　
    # Write result to the screen
　　
    write-host "Encrypted Password is: $encrypted"
　　
    write-host ""
　　

　　
    write-host "Testing Decryption of Password..."
　　

　　
    # Decrypts the string and stores the decrypted value in $decrypted
　　
    $decrypted = Decrypt-String $encrypted "MyStrongPassword"
　　
    # Writes the decrpted value to the screen
　　
    write-host "Decrypted Password is: $decrypted"
　　
    write-host ""
　　
}
　　
while ($me -ne 1)