Question

I’m currently trying to encode data before storing it to my database.

try
{
    byte[] byteEncString = new byte[_strToConvert.Length];
    byteEncString = System.Text.Encoding.UTF8.GetBytes(_strToConvert);
    string strEncoded = Convert.ToBase64String(byteEncString);
    return strEncoded;
}

Does anybody know how long a 15 character string will be after it is encoded via utf8 and base64string? Also, is there a max? My field on sql server is only 50 and i want to limit it in that range. Thoughts?

Answer 1

Well, for one thing there’s no point in creating a byte array and then ignoring it – so your code would be simpler as:

byte[] byteEncString = Encoding.UTF8.GetBytes(_strToConvert);
return Convert.ToBase64String(byteEncString);

A .NET char can end up as 3 bytes when UTF-8 encoded¹, so that gets to a 45 byte maximum. However, base64 converts 3 bytes to 4 characters, so that gives a 60 character maximum base64 encoded string as the result.

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¹ This is because any characters not in the basic multilingual plane are represented as a surrogate pair. That pair would end up as 4 bytes, but having taken 2 input characters, so the average “bytes per char” in that case is only 2.