<%@ WebHandler Language="VB" Class="ver" %>

Imports System
Imports System.Web

Public Class ver : Implements IHttpHandler
    
    Public Sub ProcessRequest(ByVal context As HttpContext) Implements IHttpHandler.ProcessRequest
        context.Response.ContentType = "text/plain"
        context.Response.Write(Encrypt(Now))
    End Sub
 
    Public ReadOnly Property IsReusable() As Boolean Implements IHttpHandler.IsReusable
        Get
            Return False
        End Get
    End Property
    Public Function Encrypt(ByVal plainText As String) As String

        Dim passPhrase As String = "date"
        Dim saltValue As String = "mySaltValue"
        Dim hashAlgorithm As String = "SHA1"

        Dim passwordIterations As Integer = 2
        Dim initVector As String = "@1B2c3D4e5F6g7H8"
        Dim keySize As Integer = 256

        Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)
        Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)

        Dim plainTextBytes As Byte() = Encoding.UTF8.GetBytes(plainText)


        Dim password As New System.Security.Cryptography.PasswordDeriveBytes(passPhrase, saltValueBytes, hashAlgorithm, passwordIterations)

        Dim keyBytes As Byte() = password.GetBytes(keySize \ 8)
        Dim symmetricKey As New System.Security.Cryptography.RijndaelManaged()

        symmetricKey.Mode = System.Security.Cryptography.CipherMode.CBC

        Dim encryptor As System.Security.Cryptography.ICryptoTransform = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)

        Dim memoryStream As New IO.MemoryStream()
        Dim cryptoStream As New System.Security.Cryptography.CryptoStream(memoryStream, encryptor, System.Security.Cryptography.CryptoStreamMode.Write)

        cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length)
        cryptoStream.FlushFinalBlock()
        Dim cipherTextBytes As Byte() = memoryStream.ToArray()
        memoryStream.Close()
        cryptoStream.Close()
        Dim cipherText As String = Convert.ToBase64String(cipherTextBytes)
        Return cipherText
    End Function
End Class