Public key to string

Question

Hello experts

I need to insert a certificate public key to a vcf contact file as Base64 string.

According to RFC 2426 section 3.7.2

It's like:

KEY;X509;ENCODING=BASE64:
 A1UEBhMCSVQxEDAOBgNVBAgCB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8x
 A1UEBhMCSVQxEDAOBgNVBAgCB0JlcmdhbW8xGTAXBgNVBAcMEFBvbnRlIFNhbiBQaWV0cm8x
 fNtkzg==

On the beginning of each line there's space, then 72 chars and line wrap, this is the public key indeed, anyone knows about the existing functions in .net 4 that will do the task?

Thanks in advance.

Answer 1

Hi @StewartBW ,

You can use the Convert.ToBase64String method to convert the certificate to a Base64 string.

Then format the Base64 string to adhere to the RFC 2426 specification by spliting the Base64 string into 72-character lines, prefixed by a space.

    Function FormatBase64String(ByVal base64String As String) As String
        Const lineLength As Integer = 72
        Dim formattedString As New StringBuilder()
        Dim currentIndex As Integer = 0

        While currentIndex < base64String.Length
            Dim length As Integer = Math.Min(lineLength, base64String.Length - currentIndex)
            formattedString.Append(" ") ' Add a space at the beginning of each line
            formattedString.AppendLine(base64String.Substring(currentIndex, length))
            currentIndex += length
        End While

        Return formattedString.ToString()
    End Function

Best Regards.

Jiachen Li

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