Encode int to the Base64-encoded byte array : Encoding Based64 « I18N Internationalization « C# / CSharp Tutorial

using System;
using System.IO;
using System.Text;

class MainClass
{
    public static void Main() 
    {

        // Get a byte representation of the int.
        byte[] b = BitConverter.GetBytes(123);

        // Return the Base64-encoded int.
        string str =  Convert.ToBase64String(b);
        Console.WriteLine(str);
        
        b = Convert.FromBase64String(str);

        // Return the decoded int.
        int i =  BitConverter.ToInt32(b,0);
        
        Console.WriteLine(i);
    }
}

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21.11.Encoding Based64
	21.11.1.	Base64 encode a Unicode string as a string
	21.11.2.	Decode a Base64-encoded Unicode string from a string
	21.11.3.	Decode the Base64-encoded int to a byte array
	21.11.4.	Encode int to the Base64-encoded byte array