1.首先在vs2008中，新建项目选择c#项目->类库
编写一下代码
using System;
using System.IO;using System.Text;using System.Security.Cryptography;using System.Runtime.InteropServices;namespace JCCT.Security
{ /*应用于VB6的dll调用*/ //首先建立接口，这个是Com必须使用的 [ComVisible(true)] [Guid("4B6FD86C-B096-4e6a-AC7F-442A51FA0776")] public interface IEncrypt { string AESEncrypt(string plainStr); string AESDecrypt(string encryptStr); }//写接口的实现
[ComVisible(true)] [Guid("367BF149-DBB3-4184-9A5C-978CC8C10787")] [ProgId("ClassLibrary1.AES")] public class AES : IEncrypt {/// <summary>
/// 获取密钥 /// </summary> private static string Key { get { return @"HJ(S<?l78242^&WL%#jCD8dkiI39(euw"; } }/// <summary>
/// 获取向量 /// </summary> private static string IV { get { return @""; } }/// <summary>
/// AES加密 /// </summary> /// <param name="plainStr">明文字符串</param> /// <returns>密文</returns> public string AESEncrypt(string plainStr) { byte[] bKey = Encoding.UTF8.GetBytes(Key); byte[] bIV = Encoding.UTF8.GetBytes(IV); byte[] byteArray = Encoding.UTF8.GetBytes(plainStr);string encrypt = null;
Rijndael aes = Rijndael.Create(); try { using (MemoryStream mStream = new MemoryStream()) { using (CryptoStream cStream = new CryptoStream(mStream, aes.CreateEncryptor(bKey, bIV), CryptoStreamMode.Write)) { cStream.Write(byteArray, 0, byteArray.Length); cStream.FlushFinalBlock(); encrypt = Convert.ToBase64String(mStream.ToArray()); } } } catch { } aes.Clear();return encrypt;
}/// <summary>
/// AES解密 /// </summary> /// <param name="encryptStr">密文字符串</param> /// <returns>明文</returns> public string AESDecrypt(string encryptStr) { string decrypt = null; Rijndael aes = Rijndael.Create(); try { byte[] bKey = Encoding.UTF8.GetBytes(Key); byte[] bIV = Encoding.UTF8.GetBytes(IV); byte[] byteArray = Convert.FromBase64String(encryptStr); using (MemoryStream mStream = new MemoryStream()) { using (CryptoStream cStream = new CryptoStream(mStream, aes.CreateDecryptor(bKey, bIV), CryptoStreamMode.Write)) { cStream.Write(byteArray, 0, byteArray.Length); cStream.FlushFinalBlock(); decrypt = Encoding.UTF8.GetString(mStream.ToArray()); } } } catch { decrypt = encryptStr; } aes.Clear();return decrypt;
} } }2.在文件AssemblyInfo.cs中，设置[assembly: ComVisible(true)]，默认是false的,需要设置成true
3.选择项目属性，在生成标签卡中，勾选为com互操作注册.
4.生成项目dll文件。
Guid生成:在工具->创建Guid生成，格式选择第四种，点复制之后需要把两边的{}除掉.
5.注册.regasm ClassLibrary1.dll /tlb:ClassLibrary1.tlb
如果点项目右键属性：
6.在vb6 中引用ClassLibrary1.tlb文件，注意不是ClassLibrary1.dll文件
引用的话，在vb6编写时可以看到ClassLibrary1的类的方法。
Dim obj As Object
Set obj = CreateObject("ClassLibrary1.AES") Form1.Text2.Text = obj.AESDecrypt(Form1.Text1.Text)当用VB6生成的应用程序，拷贝到其它机上，又不能运行了，提示：ACTIVEX 不能创建对象。后终于找到解决办法：
用命令：regasm path +ClassLibrary.dll /tlb:ClassLibrary.tlb /codebase如果用vb6生成dll文件在c#访问方法：
方法很简单 只需要生成dll, 然后在C#中引用就行了。