Wanna ask about my licensing algorithm, I create some code for encrypt a serialize object with symmetric key (Rijndael) and then encrypt the symmetric key with asymmetric key (RSA). Data is encrypt with Public-APP key but sign with Private-LS key. Then put RSA-encrypted key, RSA-encrypted IV, Rijndael-encrypted data, and signdata into an serialize object, serialize it and put to file. But when I load the data to verified it, it always failed to verified data (using verifydata). When I skip the verifying step to deserializing step, it always throw exception
System.Runtime.Serialization.SerializationException: 'End of Stream encountered before parsing was completed.'
this is code for creating file
Private Sub Button3_Click(sender As Object, e As EventArgs) Handles Button3.Click
varLicense = New LicenseInfo With {
..LICENSE INFO..
}
sfd.ShowDialog()
Dim FilePath As String = sfd.FileName
'Convert License to Byte
Dim ms As New MemoryStream
Dim bf As New BinaryFormatter()
bf.Serialize(ms, varLicense)
Dim byteLicense As Byte() = ms.ToArray
ms.Close()
'Generate random symetricKey
Dim validPassChar As String = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@#$%^&*()-+="
Dim res As New StringBuilder()
Dim rnd As New Random()
Dim lPass As Integer = 50
While (0 < lPass)
res.Append(validPassChar(rnd.Next(validPassChar.Length)))
lPass = lPass - 1
End While
'Generate key
Dim rmEnc As New RijndaelManaged()
rmEnc.BlockSize = 256
Dim pwdGen As New Rfc2898DeriveBytes(res.ToString, 1993)
Dim key As Byte() = pwdGen.GetBytes(rmEnc.KeySize / 8)
Dim IV As Byte() = pwdGen.GetBytes(rmEnc.BlockSize / 8)
'Encrypt Data License with Symetric Key
Dim varDataEnc As Byte() = symEncrypt(key, IV, byteLicense)
'Encrypt Symetric Key with RSA Public APP Key
Dim RSA = New RSACryptoServiceProvider()
RSA.FromXmlString(Project1.My.Resources.public_key_APP)
Dim keyCipher = RSA.Encrypt(key, True)
Dim ivCipher = RSA.Encrypt(IV, True)
'sign the hash with RSA Private LS Key
RSA = New RSACryptoServiceProvider()
RSA.FromXmlString(Project1.My.Resources.private_key_LS)
Dim hash = RSA.SignData(byteLicense, New SHA512CryptoServiceProvider)
'initialize final license
Dim fnLicense As New FinalLicense
fnLicense.secret_key = keyCipher
fnLicense.secret_IV = ivCipher
fnLicense.data = varDataEnc
fnLicense.hash_sign = hash
'save license to file
Dim fs As New FileStream(FilePath, FileMode.OpenOrCreate)
bf.Serialize(fs, fnLicense)
fs.Close()
MsgBox("License Created!", vbOKOnly)
End Sub
This is for reading file
Public Function LoadLicense() As Boolean
Dim fs As New FileStream(ofd.FileName, FileMode.Open)
Dim bf As New BinaryFormatter()
Dim fnlLicense As FinalLicense = bf.Deserialize(fs)
fs.Close()
'Decrypt Symetric Key with RSA
Dim RSA = New RSACryptoServiceProvider()
RSA.FromXmlString(Project1.My.Resources.private_key_APP)
Dim symKey = RSA.Decrypt(fnlLicense.secret_key, True)
Dim symIV = RSA.Decrypt(fnlLicense.secret_IV, True)
'Decrypt data with sym key
Dim data As Byte() = symDecrypt(symKey, symIV, fnlLicense.data)
'SIGNATURE CHECK
Dim RSAX = New RSACryptoServiceProvider()
RSAX.FromXmlString(Project1.My.Resources.public_key_LS)
If (RSAX.VerifyData(data, New SHA512CryptoServiceProvider, fnlLicense.hash_sign)) Then
'decapsulation
'tried jump here but throw
'System.Runtime.Serialization.SerializationException: 'End of Stream encountered before parsing was completed.'
Dim ms As New MemoryStream(data)
ms.Position = 0
Dim varLicense As LicenseInfo = bf.Deserialize(ms)
ms.Close()
Me.LICENSE_INFO = varLicense
Return True
Else
Return False
End If
End Function
and this is what i use for symmetric encryption
Public Function symEncrypt(key As Byte(), IV As Byte(), data As Byte()) As Byte()
Dim rmEnc As New RijndaelManaged()
rmEnc.BlockSize = 256
rmEnc.Key = key
rmEnc.IV = IV
Dim ms As New MemoryStream
Dim cs As New CryptoStream(ms, rmEnc.CreateEncryptor, CryptoStreamMode.Write)
Dim output As Byte()
cs.Write(data, 0, data.Length)
output = ms.ToArray
ms.Close()
Return output
End Function
Private Function symDecrypt(key As Byte(), iv As Byte(), data As Byte()) As Byte()
Dim rmEnc As New RijndaelManaged()
rmEnc.BlockSize = 256
rmEnc.Key = key
rmEnc.IV = iv
Dim ms As New MemoryStream
Dim cs As New CryptoStream(ms, rmEnc.CreateDecryptor, CryptoStreamMode.Write)
Dim output As Byte()
cs.Write(data, 0, data.Length)
output = ms.ToArray
ms.Close()
Return output
End Function
