如何编码和解码base64字符串？

编码

public static string base64Enpre(string plainText) {  var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);  return System.Convert.Tobase64String(plainTextBytes);}

解码

public static string base64Depre(string base64EnpredData) {  var base64EnpredBytes = System.Convert.Frombase64String(base64EnpredData);  return System.Text.Encoding.UTF8.GetString(base64EnpredBytes);}