Question

Have been trying to encrypt an xml file to a string so that I may transfer it over a service. The transmission is from server to server using a symetric key compiled into the code.

I have been using the AES sample from MSDN and then converting the byte arry to and from a string like so:

    ' Encrypt the string to an array of bytes.
    Dim encrypted As Byte() = crypto.EncryptString(original, _key, _iv)

    Dim encrypStr As String = Encoding.Unicode.GetString(encrypted)
    '''' >>> Transmit...
    Dim postTrans As Byte() = Encoding.Unicode.GetBytes(encrypStr)

    ' Decrypt the bytes to a string.
    Dim roundtrip As String = crypto.DecryptString(postTrans, _key, _iv)

Without the middle two line the encrypt/decrypt works fine, with the middle two lines included I either recieve a badly formed xml document that cannot be parsed or a “Padding is invalid and cannot be removed” error.

Is this not a good method for string encryption? It works perfectly without converting the byte() to string ad back.

Answer 1

Do not use Encoding.GetString(), will not always work. Use ToBase64()

Thanks to Henk Holterman for the answer.