Imports System

        Imports System.Text

        Imports System.Security.Cryptography

​

        Public Class Utils

​

            Public Shared Function DecryptString(EncryptedString As String) As String

                If String.IsNullOrEmpty(EncryptedString) Then

                    Return String.Empty

                Else

                    Return Decrypt(EncryptedString, "N3st22", "88552299", 2, "464R5DFA5DL6LE28", 256)

                End If

            End Function

​

            Public Shared Function EncryptString(PlainString As String) As String

                If String.IsNullOrEmpty(PlainString) Then

                    Return String.Empty

                Else

                    Return Encrypt(PlainString, "N3st22", "88552299", 2, "464R5DFA5DL6LE28", 256)

                End If

            End Function

​

            Public Shared Function Encrypt(ByVal plainText As String, _

                                           ByVal passPhrase As String, _

                                           ByVal saltValue As String, _

                                            ByVal passwordIterations As Integer, _

                                           ByVal initVector As String, _

                                           ByVal keySize As Integer) _

                                   As String

​

                Dim initVectorBytes As Byte() = Encoding.ASCII.GetBytes(initVector)

                Dim saltValueBytes As Byte() = Encoding.ASCII.GetBytes(saltValue)

                Dim plainTextBytes As Byte() = Encoding.ASCII.GetBytes(plainText)

                Dim password As New Rfc2898DeriveBytes(passPhrase, _

                                                   saltValueBytes, _

                                                   passwordIterations)

                Dim keyBytes As Byte() = password.GetBytes(CInt(keySize / 8))

                Dim symmetricKey As New AesCryptoServiceProvider

                symmetricKey.Mode = CipherMode.CBC

                Dim encryptor As ICryptoTransform = symmetricKey.CreateEncryptor(keyBytes, initVectorBytes)

                Using memoryStream As New IO.MemoryStream()

                    Using cryptoStream As New CryptoStream(memoryStream, _

                                                    encryptor, _

                                                    CryptoStreamMode.Write)

                        cryptoStream.Write(plainTextBytes, 0, plainTextBytes.Length)

                        cryptoStream.FlushFinalBlock()

                        Dim cipherTextBytes As Byte() = memoryStream.ToArray()

                        memoryStream.Close()

                        cryptoStream.Close()

                        Return Convert.ToBase64String(cipherTextBytes)

                    End Using

                End Using

            End Function

​

            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

​

                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

​

​

​

        Public Module Module1

​

            Public Sub Main()

                    Console.Write(Utils.DecryptString("yyEq0Uvvhq2uQOcWG8peLoeRQehqip/fKdeG/kjEVb4="))

            End Sub

​

        End Module