المثال الذي وضعته لك يشفر كل أنواع الملفات مثل الصور و التكست و قواعد البيانات و حتى ملفات التنفيذية أي يشفر كل أنواع الملفات بلا استثناء .
إذا كنت تقصد تشفير ما بداخل الملف فهذا مثال على ذلك مأخوذ من هذه المشاركة ( منقول ) :
كود :
Public Function Encrypt(ByVal text As String, ByVal key As String) As String
Try
Dim crp As New TripleDESCryptoServiceProvider
Dim uEncode As New UnicodeEncoding
Dim bytPlainText() As Byte = uEncode.GetBytes(text)
Dim stmCipherText As New MemoryStream
Dim slt() As Byte = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}
Dim pdb As New Rfc2898DeriveBytes(key, slt)
Dim bytDerivedKey() As Byte = pdb.GetBytes(24)
crp.Key = bytDerivedKey
crp.IV = pdb.GetBytes(8)
Dim csEncrypted As New CryptoStream(stmCipherText, crp.CreateEncryptor(), CryptoStreamMode.Write)
csEncrypted.Write(bytPlainText, 0, bytPlainText.Length)
csEncrypted.FlushFinalBlock()
Return Convert.ToBase64String(stmCipherText.ToArray())
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
Return Nothing
End Try
End Function
Function Decrypt(ByVal text As String, ByVal key As String) As String
Dim crp As TripleDESCryptoServiceProvider
Try
crp = New TripleDESCryptoServiceProvider
Dim uEncode As New UnicodeEncoding
Dim bytCipherText() As Byte = Convert.FromBase64String(text)
Dim stmPlainText As New MemoryStream
Dim stmCipherText As New MemoryStream(bytCipherText)
Dim slt() As Byte = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}
Dim pdb As New Rfc2898DeriveBytes(key, slt)
Dim bytDerivedKey() As Byte = pdb.GetBytes(24)
crp.Key = bytDerivedKey
crp.IV = pdb.GetBytes(8)
Dim csDecrypted As New CryptoStream(stmCipherText, crp.CreateDecryptor(), CryptoStreamMode.Read)
Dim sw As New StreamWriter(stmPlainText)
Dim sr As New StreamReader(csDecrypted)
sw.Write(sr.ReadToEnd)
sw.Flush()
csDecrypted.Clear()
crp.Clear()
Return uEncode.GetString(stmPlainText.ToArray())
Catch ex As Exception
MsgBox(ex.Message, MsgBoxStyle.Critical, "Error")
Return Nothing
End Try
End Function