Simple AES wrapper

Aes.cs

using System.Security.Cryptography;

public static class Aes
{
    public static byte[] Encrypt(byte[] data, byte[] key)
    {
        if (data == null)
            throw new ArgumentNullException("data");
        if (key == null)
            throw new ArgumentNullException("key");

        using (var aes = new RijndaelManaged {Key = GetKey(key), Mode = CipherMode.ECB})
        {
            var enc = aes.CreateEncryptor();
            return enc.TransformFinalBlock(data, 0, data.Length);
        }
    }

    public static byte[] Decrypt(byte[] data, byte[] key)
    {
        if (data == null)
            throw new ArgumentNullException("data");
        if (key == null)
            throw new ArgumentNullException("key");

        using (var aes = new RijndaelManaged {Key = GetKey(key), Mode = CipherMode.ECB})
        {
            var enc = aes.CreateDecryptor();
            return enc.TransformFinalBlock(data, 0, data.Length);
        }
    }

    private static byte[] GetKey(byte[] key)
    {
        using (var provider = new SHA256CryptoServiceProvider())
        {
            return provider.ComputeHash(key);
        }
    }
}