Decode password using C#

public string base64Decode(string sData)

{

System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();

System.Text.Decoder utf8Decode = encoder.GetDecoder();

byte[] todecode_byte = Convert.FromBase64String(sData);

int charCount = utf8Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length);

char[] decoded_char = new char[charCount];

utf8Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);

string result = new String(decoded_char);

return result;

}