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December 10th, 2008

Encoding and Decoding Binary data using Base64 with C# - 1

It is often necessary to convert binary data to and from strings. One common way of encoding such information is through Base-64 encoding. The following post shows you how to convert a byte array to a Base64 string , and back again.

What is Base64?

Base-64 encoded information uses the most common characters: A-Z,a-z and 0-9, allowing for save storage of binary date in places that do not support binary.

The most common situation is e-mail, but it is also often used to encode binary data in XML files or other text file formats.

An example of Base-64 encoded data:


Implementing it in C#

The following example shows how to convert a byte array to a base-64 encoded string and back again. All the actual work is done by the System.Convert class. In the example below we use System.Security.Cryptography to fill our test array with random data.

using System;
using System.Security.Cryptography;

namespace Base64
    class MainClass
        public static bool VerifyEqual(byte[] one, byte[] two)
            if (one.Length != two.Length) return false;
            for (int Lp = 0; Lp < one.Length; Lp++)
                if (!one[Lp].Equals(two[Lp])) return false;
            return true;
        public static void Main(string[] args)
            byte[] DataToEncode = new byte[30];
            // Fill the byte array with random data
            RandomNumberGenerator Generator = RandomNumberGenerator.Create();
            // Convert the byte array to a base-64 string
            string Base64String = Convert.ToBase64String(DataToEncode);

            // Convert the base-64 string back to a byte array
            byte[] DecodedData = Convert.FromBase64String(Base64String);

            // Verify that the data was decoded correctly
            if (!VerifyEqual(DecodedData,DataToEncode))
                Console.WriteLine("Byte[]'s do not match!");
                Console.WriteLine("Byte[]'s match!");
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One Response to “Encoding and Decoding Binary data using Base64 with C#”

  1. denglish Says:

    Thank you for the code, this helped me complete and important project. I referenced you in my blog documentation.

    Best regards, denglish

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