使用微软企业库连接数据库时，对数据库连接字符串进行加密，多种数据库皆可行

微软企业库是开源的，原本是无法对数据库配置的连接字符串进行加密的，但是既然是开源的那就把源码下载下来，想怎么改就怎么改，比如说我这种改法，把Database类的ConnectionString由只读变为可写，那么便可如下方代码一样，对数据库的加密连接字符串进行解密了：

using Microsoft.Practices.EnterpriseLibrary.Common.Configuration;
using Microsoft.Practices.EnterpriseLibrary.Data;
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Common;
using System.IO;
using System.Linq;
using System.Security.Cryptography;
using System.Text;

namespace ShiYanXiangMu
{
    public static class DBHelper
    {
        /// <summary>
        /// 创建Database对象
        /// </summary>
        /// <param name="connectionStrings">使用的连接字符串名称，如果传空则使用配置文件中默认指定的</param>
        /// <param name="secretKey">如果连接字符串为DES密文，则传输DES解密密钥，如果为明文则传空即可</param>
        /// <returns></returns>
        static Database getDb(string connectionStrings = null, string secretKey = null)
        {
            DatabaseFactory.SetDatabaseProviderFactory(new DatabaseProviderFactory(new SystemConfigurationSource(false).GetSection), false);
            Database db;
            if (string.IsNullOrEmpty(connectionStrings))
            {
                db = DatabaseFactory.CreateDatabase();
            }
            else
            {
                db = DatabaseFactory.CreateDatabase(connectionStrings);
            }
            if (!string.IsNullOrEmpty(secretKey))//如果密钥入参不为空，那么使用该密钥对连接字符串进行解密
            {
                db.ConnectionString = Decrypt(db.ConnectionString, secretKey);
            }
            return db;
        }

        public static DataTable GetTableBySql(string sql, DbParameter[] parameters = null, DbTransaction trans = null, string connectionStrings = null, string secretKey = null)
        {
            Database db = getDb(connectionStrings,secretKey:"19950710");
            DbCommand command = db.GetSqlStringCommand(sql);
            if (parameters != null)
            {
                foreach (DbParameter param in parameters)
                {
                    db.AddInParameter(command, param.ParameterName, param.DbType, param.Value);
                }
            }
            DataTable dt = null;
            if (trans != null)
            {
                dt = db.ExecuteDataSet(command, trans).Tables[0];
            }
            else
            {
                dt = db.ExecuteDataSet(command).Tables[0];
            }

            if (dt != null)
            {
                dt.TableName = "tableName";//增加一个表名称，防止WCF方式因为TableName为空出错
            }

            return dt;
        }

        /// <summary>
        /// DES加密
        /// </summary>
        /// <param name="str">需要加密的</param>
        /// <param name="sKey">密匙</param>
        /// <returns></returns>
        private static string Encrypt(string str, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Encoding.Default.GetBytes(str);
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);// 密匙
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);// 初始化向量
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            cs.FlushFinalBlock();
            var retB = Convert.ToBase64String(ms.ToArray());
            return retB;
        }

        /// <summary>
        /// DES解密
        /// </summary>
        /// <param name="pToDecrypt">需要解密的</param>
        /// <param name="sKey">密匙</param>
        /// <returns></returns>
        private static string Decrypt(string pToDecrypt, string sKey)
        {
            DESCryptoServiceProvider des = new DESCryptoServiceProvider();
            byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);
            des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
            des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
            MemoryStream ms = new MemoryStream();
            CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
            cs.Write(inputByteArray, 0, inputByteArray.Length);
            // 如果两次密匙不一样，这一步可能会引发异常
            cs.FlushFinalBlock();
            return System.Text.Encoding.Default.GetString(ms.ToArray());
        }
    }
}

 

下面链接提供已进行修改的微软企业库dll文件，这是根据最新的企业库6作的修改，改动也就是上面所述的Database类的ConnectionString属性，别的都是原汁原味的功能，如有依赖微软企业库，又要对数据库连接字符串进行加密的同学可以拿去使用。

微软企业库数据库连接dll文件，含使用示例