Base32 Encoding and Decoding in C#

You might have to do some Base32 Encoding or Decoding in C# (or PowerShell). Here's a simple .NET implementation in C# you can use!

using System; using System.Linq; using System.Text; public static class Base32 { /// <summary> /// The different characters allowed in Base32 encoding. /// </summary> /// <remarks> /// This is a 32-character subset of the twenty-six letters A–Z and six digits 2–7. /// <see cref="https://en.wikipedia.org/wiki/Base32" /> /// </remarks> private const string Base32AllowedCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"; /// <summary> /// Converts a byte array into a Base32 string. /// </summary> /// <param name="input">The string to convert to Base32.</param> /// <param name="addPadding">Whether or not to add RFC3548 '='-padding to the string.</param> /// <returns>A Base32 string.</returns> /// <remarks> /// https://tools.ietf.org/html/rfc3548#section-2.2 indicates padding MUST be added unless the reference to the RFC tells us otherswise. /// https://github.com/google/google-authenticator/wiki/Key-Uri-Format indicates that padding SHOULD be omitted. /// To meet both requirements, you can omit padding when required. /// </remarks> public static string ToBase32String(this byte[] input, bool addPadding = true) { if (input == null || input.Length == 0) { return string.Empty; } var bits = input.Select(b => Convert.ToString(b, 2).PadLeft(8, '0')).Aggregate((a, b) => a + b).PadRight((int)(Math.Ceiling((input.Length * 8) / 5d) * 5), '0'); var result = Enumerable.Range(0, bits.Length / 5).Select(i => Base32AllowedCharacters.Substring(Convert.ToInt32(bits.Substring(i * 5, 5), 2), 1)).Aggregate((a, b) => a + b); if (addPadding) { result = result.PadRight((int)(Math.Ceiling(result.Length / 8d) * 8), '='); } return result; } public static string EncodeAsBase32String(this string input, bool addPadding = true) { if (string.IsNullOrEmpty(input)) { return string.Empty; } var bytes = Encoding.UTF8.GetBytes(input); var result = bytes.ToBase32String(addPadding); return result; } public static string DecodeFromBase32String(this string input) { if (string.IsNullOrEmpty(input)) { return string.Empty; } var bytes = input.ToByteArray(); var result = Encoding.UTF8.GetString(bytes); return result; } /// <summary> /// Converts a Base32 string into the corresponding byte array, using 5 bits per character. /// </summary> /// <param name="input">The Base32 String</param> /// <returns>A byte array containing the properly encoded bytes.</returns> public static byte[] ToByteArray(this string input) { if (string.IsNullOrEmpty(input)) { return new byte[0]; } var bits = input.TrimEnd('=').ToUpper().ToCharArray().Select(c => Convert.ToString(Base32AllowedCharacters.IndexOf(c), 2).PadLeft(5, '0')).Aggregate((a, b) => a + b); var result = Enumerable.Range(0, bits.Length / 8).Select(i => Convert.ToByte(bits.Substring(i * 8, 8), 2)).ToArray(); return result; } }

(Sorry about the formatting, but Visual Studio will sort it out for you!)