SigParser Decoder Example

decoder.cs

///<summary>
/// Decode Base64 encoded string with URL and Filename Safe Alphabet using UTF-8.
///</summary>
///<param name="str">Base64 code</param>
///<returns>The decoded string.</returns>
public static string DecodeBase64(string str)
{
    if (str == null)
        return str;
    int padChars = (str.Length % 4) == 0 ? 0 : (4 - (str.Length % 4));
    StringBuilder result = new StringBuilder(str, str.Length + padChars);
    result.Append(String.Empty.PadRight(padChars, '='));
    result.Replace('-', '+');
    result.Replace('_', '/');
    var data = Convert.FromBase64String(result.ToString());

    string decodedString = Encoding.UTF8.GetString(data);
    return decodedString;
}