cer.cs

使用RSACryptoServiceProvider和X509Certificate2进行证书加密解密

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Xml;
using System.Security.Cryptography;
using System.Security.Permissions;
using System.Security.Cryptography.X509Certificates;
using System.Runtime.InteropServices;
using System.ComponentModel;

namespace WindowsApplication1
{
    /// <summary>
    /// 使用RSACryptoServiceProvider和X509Certificate2进行证书加密解密
    /// 平台：.NET 2.0
    /// </summary>
    public class CertificateEncryptedDecrypted
    {
        static string mDigitalCertificateName = "";

        [Description("证书名称")]
        public static string DigitalCertificateName
        {
            get
            {
                return mDigitalCertificateName;
            }
            set
            {
                mDigitalCertificateName = value;
            }
        }

        /// <summary>
        /// 获取密文
        /// </summary>
        /// <param name="cPlainStringToEncrypt">明文</param>
        /// <returns></returns>
        public static string GetEncryptedText(string cPlainStringToEncrypt)
        {
            X509Store store = new X509Store(StoreName.My);
            X509Certificate2 x509_2 = null;
            store.Open(OpenFlags.ReadWrite);
            if (mDigitalCertificateName.Length > 0)
            {
                foreach (X509Certificate2 cert in store.Certificates)
                {
                    if (cert.SubjectName.Name.Contains(mDigitalCertificateName))
                    {
                        x509_2 = cert;
                        break;
                    }
                }
                if (x509_2 == null)
                    throw new Exception("不能找到证书：" + mDigitalCertificateName);
            }
            else
            {
                x509_2 = store.Certificates[0];
            }
            try
            {
                string PlainString = cPlainStringToEncrypt.Trim();
                byte[] cipherbytes = ASCIIEncoding.ASCII.GetBytes(PlainString);
                RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)x509_2.PublicKey.Key;
                byte[] cipher = rsa.Encrypt(cipherbytes, false);
                return Convert.ToBase64String(cipher);
            }
            catch (Exception e)
            {
                throw e;
            }
        }

        /// <summary>
        /// 获取译文
        /// </summary>
        /// <param name="cEncryptedStringToDecrypt">密文</param>
        /// <returns></returns>
        public static string GetDecryptedText(string cEncryptedStringToDecrypt)
        {
            X509Store store = new X509Store(StoreName.My);
            X509Certificate2 x509_2 = null;
            store.Open(OpenFlags.ReadWrite);
            if (mDigitalCertificateName.Length > 0)
            {
                foreach (X509Certificate2 cert in store.Certificates)
                {
                    if (cert.SubjectName.Name.Contains(mDigitalCertificateName))
                    {
                        x509_2 = cert;
                        break;
                    }
                }
                if (x509_2 == null)
                    throw new Exception("不能找到证书：" + mDigitalCertificateName);
            }
            else
            {
                x509_2 = store.Certificates[0];
            }
            try
            {
                byte[] cipherbytes = Convert.FromBase64String(cEncryptedStringToDecrypt);
                if (x509_2.HasPrivateKey)
                {
                    RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)x509_2.PrivateKey;
                    byte[] plainbytes = rsa.Decrypt(cipherbytes, false);
                    System.Text.ASCIIEncoding enc = new System.Text.ASCIIEncoding();
                    return enc.GetString(plainbytes);
                }
                else
                {
                    throw new Exception("证书没有使用私钥");
                }
            }
            catch (Exception e)
            {
                throw e;
            }
        }
    }
}