[C#] long(Int64) 與 base64 互轉

// long(Int64) 轉 base64

var buffer1 = BitConverter.GetBytes(long.MaxValue);

string str = Convert.ToBase64String(buffer1);

// base6轉long(Int64)

var buffer2 = Convert.FromBase64String(str);

long val = BitConverter.ToInt64(buffer2, 0);