TinyCrypt.cs

    ///
    /// <summary>
    /// Encrypt and compress data in one. Invented by gigajew.
    /// </summary>
    ///
    public class TinyCrypt {

        private Random _random;
        private byte[] _key;

        public byte[] Key {
            get {
                return _key;
            }
            private set {
                _key = value;
            }
        }

        public byte[] Encrypt(byte[] data, byte[] key = null) {
            if(key != null) {
                Key = key;
            }
            using (MemoryStream memory = new MemoryStream()) {
                data = Compress(data);
                for (int i = 0; i < data.Length; i++)
                {
                    data[i] ^= Key[i % Key.Length];
                    memory.WriteByte(data[i]);
                }
                return memory.ToArray();
            }
        }

        public byte[] Decrypt(byte[] data, byte[] key = null) {
            if(key != null) {
                Key = key;
            }
            using (MemoryStream memory = new MemoryStream(data)) {
                byte[] buffer = new byte[memory.Length];
                for(int i = 0 ; i < buffer.Length; i++) {
                    buffer[i] = (byte) ((int) memory.ReadByte() ^ (int) Key[i % Key.Length]);
                }
                return Decompress(buffer);
            }
        }

        private byte[] Compress(byte[] data) {
            using (MemoryStream output = new MemoryStream())
            {
                using (GZipStream zip = new GZipStream(output, CompressionMode.Compress, true)) {
                    zip.Write(data, 0, data.Length);
                }
                return output.ToArray();
            }
        }

        private byte[] Decompress(byte[] data)
        {
            using (MemoryStream memory = new MemoryStream(data))
            using (GZipStream zip = new GZipStream(memory, CompressionMode.Decompress))
            {
                const int size = 4096;
                byte[] buffer = new byte[size];
                using (MemoryStream output = new MemoryStream())
                {
                    int count = 0;
                    do
                    {
                        count = zip.Read(buffer, 0, size);
                        if (count > 0)
                        {
                            output.Write(buffer, 0, count);
                        }
                    }
                    while (count > 0);
                    return output.ToArray();
                }
            }
        }

        public void RandomizeKey() {
            _key = new byte[4096];
            _random.NextBytes(_key);
        }

        public void RandomizeSeed() {
            _random = new Random(Guid.NewGuid().GetHashCode());
        }

        public TinyCrypt() {
            RandomizeSeed();
            RandomizeKey();
        }
    }