Base32 Decoding

Question

I have a base32 string which I need to convert to a byte array. And I\'m having trouble finding a conversion method in the .NET framework. I can find methods for base64 but

Answer 1

Here are my functions for encoding and decoding. I feel that they are much shorter and concise than the other suggestions. So if you need a small one, try these.

public static string BytesToBase32(byte[] bytes) {
    const string alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
    string output = "";
    for (int bitIndex = 0; bitIndex < bytes.Length * 8; bitIndex += 5) {
        int dualbyte = bytes[bitIndex / 8] << 8;
        if (bitIndex / 8 + 1 < bytes.Length)
            dualbyte |= bytes[bitIndex / 8 + 1];
        dualbyte = 0x1f & (dualbyte >> (16 - bitIndex % 8 - 5));
        output += alphabet[dualbyte];
    }

    return output;
}

public static byte[] Base32ToBytes(string base32) {
    const string alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
    List output = new List();
    char[] bytes = base32.ToCharArray();
    for (int bitIndex = 0; bitIndex < base32.Length * 5; bitIndex += 8) {
        int dualbyte = alphabet.IndexOf(bytes[bitIndex / 5]) << 10;
        if (bitIndex / 5 + 1 < bytes.Length)
            dualbyte |= alphabet.IndexOf(bytes[bitIndex / 5 + 1]) << 5;
        if (bitIndex / 5 + 2 < bytes.Length)
            dualbyte |= alphabet.IndexOf(bytes[bitIndex / 5 + 2]);

        dualbyte = 0xff & (dualbyte >> (15 - bitIndex % 5 - 8));
        output.Add((byte)(dualbyte));
    }
    return output.ToArray();
}