Imports System

Imports System.Text

Imports System.Security.Cryptography

Public Module Module1   

    Public Class Utils

         public Main 

        Public Shared Function Decrypt(ByVal cipherText As String, _

                                   ByVal passPhrase As String, _

                                   ByVal saltValue As String, _

                                    ByVal passwordIterations As Integer, _

                                   ByVal initVector As String, _

                                   ByVal keySize As Integer) _

                           As String

        cipherText = "fTEzAfYDoz1YzkqhQkH6GQFYKp1XY5hm7bjOP86yYxE="

        passphrase = "N3st22"

        saltValue = "88552299"

        passwordIterations = 2

        initVector = "464R5DFA5DL6LE28"

        keySize = 256

        Dim initVectorBytes As Byte()

        initVectorBytes = Encoding.ASCII.GetBytes(initVector)

​

        Dim saltValueBytes As Byte()

        saltValueBytes = Encoding.ASCII.GetBytes(saltValue)

​

        Dim cipherTextBytes As Byte()

        cipherTextBytes = Convert.FromBase64String(cipherText)

​

        Dim password As New Rfc2898DeriveBytes(passPhrase, _

                                           saltValueBytes, _

                                           passwordIterations)

​

        Dim keyBytes As Byte()

        keyBytes = password.GetBytes(CInt(keySize / 8))

​

        Dim symmetricKey As New AesCryptoServiceProvider

        symmetricKey.Mode = CipherMode.CBC

​

        Dim decryptor As ICryptoTransform

        decryptor = symmetricKey.CreateDecryptor(keyBytes, initVectorBytes)

​

        Dim memoryStream As IO.MemoryStream

        memoryStream = New IO.MemoryStream(cipherTextBytes)

​

        Dim cryptoStream As CryptoStream

        cryptoStream = New CryptoStream(memoryStream, _

                                        decryptor, _

                                        CryptoStreamMode.Read)

​

        Dim plainTextBytes As Byte()

        ReDim plainTextBytes(cipherTextBytes.Length)

​

        Dim decryptedByteCount As Integer

        decryptedByteCount = cryptoStream.Read(plainTextBytes, _

                                               0, _

                                               plainTextBytes.Length)

​

        memoryStream.Close()

        cryptoStream.Close()

​

        Dim plainText As String

        plainText = Encoding.ASCII.GetString(plainTextBytes, _

                                            0, _

                                            decryptedByteCount)

​

        Return plainText

        End Function

    End Class   

End Module

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