C#做的一个加密/解密的类

     摘要：前两年写的东西，现在整理一下发出来！以前公司需要做WebService，并且对WebService的SoapHeader进行加密，所以就写了这么个东东！使用这个类，需要密钥管理！为了保证数据的安全性往往要对数据进行加密，但是加密的缺点之一，就是影响程序的运行效率，所以，当时我的思路是只对用户的登录信息（用户名，密码）进行加密！数据用明文传输，用户信息验证没有通过的情况下, 不进行数据传输。

     前两年写的东西，现在整理一下发出来！以前公司需要做WebService，并且对WebService的SoapHeader进行加密，所以就写了这么个东东！使用这个类，需要密钥管理！为了保证数据的安全性往往要对数据进行加密，但是加密的缺点之一，就是影响程序的运行效率，所以，当时我的思路是只对用户的登录信息（用户名，密码）进行加密！数据用明文传输，用户信息验证没有通过的情况下, 不进行数据传输。

     实际在网络通讯中，使用密钥匙的方式并非无懈可击，如果黑客可以捕捉到用密钥加密的，用户验证信息，然后，做个模拟请求，向提供WebService的服务器发请求，还是可以获得请求数据！所以，我又使用了IP或者域名绑定的方式！毕竟，WebService不是直接对最终用户提供的！所以，加上以上这些手段后，就算有不良企图者想通过非法方式获得WebService提供的服务，就再费点劲吧！

     还有一点安全建议，就是定期的更换密钥，在这个例子中，我用的是对称加密，加密方和解密方的密钥一致！定期的更换密钥可以让安全性提高一大截！

     大家要有更好的方法，或者建议，可以留言讨论一下！共同提高！

代码如下：

using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;
 
namespace SEDO
{
    /// <summary>
    /// SEDO 的摘要说明。
    /// SEDO 实现的是用一个封装了4种对称加密方法(Des,Rc2,Rijndael,TripleDes)的组件
    ///
    /// 注意事项：
    /// 1:TripleDes和Rijndael加密/解密对象使用16或者24位byte的Key
    /// 2:Rijndael只能使用16位的初始化向量IV
    /// 3:Des和Rc2均使用8位Byte的Key和IV
    /// 4:对需要加密/解密的数据流采用何种方法进行编码/解码，由调用组件的用户自己决定
    /// 5:密钥和初始化向量IV由使用者自己定义
    /// 程序员： 罗旭成2010-10-30 lxc880615@163.com
    /// </summary>
 
    //定义加密类型的枚举
    public enum EncryptionAlgorithm { Des = 1, Rc2, Rijndael, TripleDes };
 
    //定义加密类
    internal class EncryptTransformer
    {
        private EncryptionAlgorithm algorithmID;
        private byte[] initVec;
        private byte[] encKey;
 
        internal EncryptTransformer(EncryptionAlgorithm algId)
        {
            //Save the algorithm being used.
            algorithmID = algId;
        }
 
        internal ICryptoTransform GetCryptoServiceProvider(byte[] bytesKey)
        {
            //当数据密钥Key或者初始化向量IV为空的时候，
            //将使用加密对象自动产生的密钥Key或者初始化向量IV
            switch (algorithmID)
            {
                case EncryptionAlgorithm.Des:
                    {
                        DES des = new DESCryptoServiceProvider();
                        des.Mode = CipherMode.CBC;
 
                        // See if a key was provided
                        if (null == bytesKey)
                        {
                            encKey = des.Key;
                        }
                        else
                        {
                            des.Key = bytesKey;
                            encKey = des.Key;
                        }
                        // See if the client provided an initialization vector
                        if (null == initVec)
                        { // Have the algorithm create one
                            initVec = des.IV;
                        }
                        else
                        { //No, give it to the algorithm
                            des.IV = initVec;
                        }
                        return des.CreateEncryptor();
                    }
                case EncryptionAlgorithm.TripleDes:
                    {
                        TripleDES des3 = new TripleDESCryptoServiceProvider();
                        des3.Mode = CipherMode.CBC;
                        // See if a key was provided
                        if (null == bytesKey)
                        {
                            encKey = des3.Key;
                        }
                        else
                        {
                            des3.Key = bytesKey;
                            encKey = des3.Key;
                        }
                        // See if the client provided an IV
                        if (null == initVec)
                        { //Yes, have the alg create one
                            initVec = des3.IV;
                        }
                        else
                        { //No, give it to the alg.
                            des3.IV = initVec;
                        }
                        return des3.CreateEncryptor();
                    }
                case EncryptionAlgorithm.Rc2:
                    {
                        RC2 rc2 = new RC2CryptoServiceProvider();
                        rc2.Mode = CipherMode.CBC;
                        // Test to see if a key was provided
                        if (null == bytesKey)
                        {
                            encKey = rc2.Key;
                        }
                        else
                        {
                            rc2.Key = bytesKey;
                            encKey = rc2.Key;
                        }
                        // See if the client provided an IV
                        if (null == initVec)
                        { //Yes, have the alg create one
                            initVec = rc2.IV;
                        }
                        else
                        { //No, give it to the alg.
                            rc2.IV = initVec;
                        }
                        return rc2.CreateEncryptor();
                    }
                case EncryptionAlgorithm.Rijndael:
                    {
                        Rijndael rijndael = new RijndaelManaged();
                        rijndael.Mode = CipherMode.CBC;
                        // Test to see if a key was provided
                        if (null == bytesKey)
                        {
                            encKey = rijndael.Key;
                        }
                        else
                        {
                            rijndael.Key = bytesKey;
                            encKey = rijndael.Key;
                        }
                        // See if the client provided an IV
                        if (null == initVec)
                        { //Yes, have the alg create one
                            initVec = rijndael.IV;
                        }
                        else
                        { //No, give it to the alg.
                            rijndael.IV = initVec;
                        }
                        return rijndael.CreateEncryptor();
                    }
                default:
                    {
                        throw new CryptographicException("Algorithm ID '" +
                        algorithmID +
                        "' not supported.");
                    }
            }
        }
 
        //加密的偏移向量
        internal byte[] IV
        {
            get { return initVec; }
            set { initVec = value; }
        }
        //加密的密钥
        internal byte[] Key
        {
            get { return encKey; }
            set { encKey = value; }
        }
 
    }
 
    //定义解密类
    internal class DecryptTransformer
    {
        private EncryptionAlgorithm algorithmID;
        private byte[] initVec;
        private byte[] encKey;
 
        internal DecryptTransformer(EncryptionAlgorithm deCryptId)
        {
            algorithmID = deCryptId;
        }
 
        //加密的偏移向量
        internal byte[] IV
        {
            get { return initVec; }
            set { initVec = value; }
        }
 
        //加密的密钥
        internal byte[] Key
        {
            get { return encKey; }
            set { encKey = value; }
        }
 
        internal ICryptoTransform GetCryptoServiceProvider(byte[] bytesKey)
        {
            //当数据密钥Key或者初始化向量IV为空的时候，
            //将使用加密对象自动产生的密钥Key或者初始化向量IV
            switch (algorithmID)
            {
                case EncryptionAlgorithm.Des:
                    {
                        DES des = new DESCryptoServiceProvider();
                        des.Mode = CipherMode.CBC;
                        des.Key = bytesKey;
                        des.IV = initVec;
                        return des.CreateDecryptor();
                    }
                case EncryptionAlgorithm.TripleDes:
                    {
                        TripleDES des3 = new TripleDESCryptoServiceProvider();
                        des3.Mode = CipherMode.CBC;
                        return des3.CreateDecryptor(bytesKey, initVec);
                    }
                case EncryptionAlgorithm.Rc2:
                    {
                        RC2 rc2 = new RC2CryptoServiceProvider();
                        rc2.Mode = CipherMode.CBC;
                        return rc2.CreateDecryptor(bytesKey, initVec);
                    }
                case EncryptionAlgorithm.Rijndael:
                    {
                        Rijndael rijndael = new RijndaelManaged();
                        rijndael.Mode = CipherMode.CBC;
                        return rijndael.CreateDecryptor(bytesKey, initVec);
                    }
                default:
                    {
                        throw new CryptographicException("Algorithm ID '" +
                        algorithmID +
                        "' not supported.");
                    }
            }
        } //end GetCryptoServiceProvider
 
    }
 
    //定义加密者类
    public class Encryptor
    {
        private EncryptTransformer transformer;
        private byte[] initVec;
        private byte[] encKey;
 
        public Encryptor(EncryptionAlgorithm algId)
        {
            transformer = new EncryptTransformer(algId);
        }
 
        public byte[] Encrypt(byte[] bytesData, byte[] bytesKey, byte[] bytesIV)
        {
            //设置流对象用来保存加密数据字节流.
            MemoryStream memStreamEncryptedData = new MemoryStream();
 
            transformer.IV = bytesIV;
            transformer.Key = bytesKey;
 
            ICryptoTransform transform =
                transformer.GetCryptoServiceProvider(bytesKey);
            CryptoStream encStream =
                new CryptoStream(memStreamEncryptedData,
                    transform, CryptoStreamMode.Write);
 
            try
            {
                //将加密数据写进流对象
                encStream.Write(bytesData, 0, bytesData.Length);
            }
            catch (Exception ex)
            {
                throw new Exception("在数据加密的时候出现错误！"+
                    "错误提示： 
" + ex.Message);
            }
 
            //设置加密的Key和初始向量IV属性
            encKey = transformer.Key;
            initVec = transformer.IV;
 
            encStream.FlushFinalBlock();
            encStream.Close();
 
            //Send the data back.
            return memStreamEncryptedData.ToArray();
        }
 
        public byte[] IV
        {
            get { return initVec; }
            set { initVec = value; }
        }
 
        public byte[] Key
        {
            get { return encKey; }
            set { encKey = value; }
        }
 
    }
 
 
    //定义解密者类
    public class Decryptor
    {
        private DecryptTransformer transformer;
        private byte[] initVec;
        private byte[] encKey;
 
        public Decryptor(EncryptionAlgorithm algId)
        {
            transformer = new DecryptTransformer(algId);
        }
 
        public byte[] Decrypt(byte[] bytesData,
            byte[] bytesKey, byte[] bytesIV)
        {
            //设置流对象用来保存解密数据字节流.
            MemoryStream memStreamDecryptedData =
                new MemoryStream();
 
            //Pass in the initialization vector.
            transformer.IV = bytesIV;
            transformer.Key = bytesKey;
 
            ICryptoTransform transform =
                transformer.GetCryptoServiceProvider(bytesKey);
            CryptoStream decStream =
                new CryptoStream(memStreamDecryptedData,
                    transform, CryptoStreamMode.Write);
 
            try
            {
                decStream.Write(bytesData, 0, bytesData.Length);
            }
            catch (Exception ex)
            {
                throw new Exception("在数据解密的时候出现错误！"+
                    "错误提示： 
" + ex.Message);
            }
            decStream.FlushFinalBlock();
            decStream.Close();
            // 返回解密数据.
            return memStreamDecryptedData.ToArray();
        }
 
        public byte[] IV
        {
            get { return initVec; }
            set { initVec = value; }
        }
 
        public byte[] Key
        {
            get { return encKey; }
            set { encKey = value; }
        }
 
    }
 
    //类描述：文件加密/解密类
    public class SecurityFile
    {
        private DecryptTransformer Dec_Transformer; //解密转换器
        private EncryptTransformer Enc_Transformer; //加密转换器
        private byte[] initVec;
        private byte[] encKey;
 
        public SecurityFile(EncryptionAlgorithm algId)
        {
            Dec_Transformer = new DecryptTransformer(algId);
            Enc_Transformer = new EncryptTransformer(algId);
        }
 
        //加密的偏移向量
        internal byte[] IV
        {
            get { return initVec; }
            set { initVec = value; }
        }
        //加密的密钥
        internal byte[] Key
        {
            get { return encKey; }
            set { encKey = value; }
        }
 
        //功能描述：加密文件
        public void EncryptFile(string inFileName,
            string outFileName, byte[] bytesKey, byte[] bytesIV)
        {
            try
            {
                FileStream fin =
                    new FileStream(inFileName, FileMode.Open,
                        FileAccess.Read);
                FileStream fout = new FileStream(outFileName,
                    FileMode.OpenOrCreate, FileAccess.Write);
                fout.SetLength(0);
 
                //Create variables to help with read and write.
                //This is intermediate storage for the encryption.
                byte[] bin = new byte[100];
                //This is the total number of bytes written.
                long rdlen = 0;
                //This is the total length of the input file.
                long totlen = fin.Length;
                //This is the number of bytes to be written at a time.
                int len; 
 
                Enc_Transformer.IV = bytesIV;
                Enc_Transformer.Key = bytesKey;
 
                ICryptoTransform transform =
                    Enc_Transformer.GetCryptoServiceProvider(bytesKey);
                CryptoStream encStream =
                    new CryptoStream(fout, transform, CryptoStreamMode.Write);
 
                //Read from the input file, then encrypt and write to the output file.
                while (rdlen < totlen)
                {
                    len = fin.Read(bin, 0, 100);
                    encStream.Write(bin, 0, len);
                    rdlen = rdlen + len;
                }
 
                encStream.Close();
                fout.Close();
                fin.Close();
            }
            catch (Exception ex)
            {
                throw new Exception("在文件加密的时候出现错误！"+
                    "错误提示： 
" + ex.Message);
            }
        }
 
        //功能描述：解密文件
        public void DecryptFile(string inFileName,
            string outFileName, byte[] bytesKey, byte[] bytesIV)
        {
            try
            {
                FileStream fin =
                    new FileStream(inFileName, FileMode.Open,
                        FileAccess.Read);
                FileStream fout =
                    new FileStream(outFileName,
                        FileMode.OpenOrCreate, FileAccess.Write);
                fout.SetLength(0);
 
                //Create variables to help with read and write.
                //This is intermediate storage for the encryption.
                byte[] bin = new byte[100];
                //This is the total number of bytes written.
                long rdlen = 0;
                //This is the total length of the input file.
                long totlen = fin.Length;
                //This is the number of bytes to be written at a time.
                int len; 
 
                Dec_Transformer.IV = bytesIV;
                Dec_Transformer.Key = bytesKey;
 
                ICryptoTransform transform =
                    Dec_Transformer.GetCryptoServiceProvider(bytesKey);
                CryptoStream encStream =
                    new CryptoStream(fout, transform, CryptoStreamMode.Write);
 
                //Read from the input file, then encrypt and
                //write to the output file.
                while (rdlen < totlen)
                {
                    len = fin.Read(bin, 0, 100);
                    encStream.Write(bin, 0, len);
                    rdlen = rdlen + len;
                }
                encStream.Close();
                fout.Close();
                fin.Close();
            }
            catch (Exception ex)
            {
                throw new Exception("在文件加密的时候出现"+
                    "错误！错误提示： 
" + ex.Message);
            }
        }
    }
}