关于DES 过程密钥和密钥分散
目前要做个项目 涉及到过程密钥及密钥分散，我想问下过程密钥、密钥分散的含义分别是什么，请举例说明
------解决方案--------------------
  public class DES
        {
            //默认密钥向量
            private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };

            /// <summary>
            /// DES加密字符串
            /// </summary>
            /// <param name="encryptString">待加密的字符串</param>
            /// <param name="encryptKey">加密密钥,要求为8位</param>
            /// <returns>加密成功返回加密后的字符串,失败返回源串</returns>
            public static string Encode(string encryptString, string encryptKey)
            {
                encryptKey = GF_GET.GetSubString(encryptKey, 8, "");
                encryptKey = encryptKey.PadRight(8, ' ');
                byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));
                byte[] rgbIV = Keys;
                byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
                DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
                MemoryStream mStream = new MemoryStream();