.NET使用OpenSSL生成的pem密钥文件(增加size为2048的密钥转换)

上篇随笔 .NET使用OpenSSL生成的pem密钥文件【做电子商务的朋友可能需要】http://www.zzzyk.com/kf/201202/121297.html 的算法只支持1024位的密钥文件导入.NET，今天把2048位的支持加上：

using System;
using System.Text;
using System.Security.Cryptography;
using System.Web;
using System.IO;

namespace Thinhunan.Cnblogs.Com.RSAUtility
{
    /// <summary>
    /// Author http://thinhunan.cnblogs.com
    /// </summary>
    public class PemConverter
    {
        /// <summary>
        /// 将pem格式公钥(1024 or 2048)转换为RSAParameters
        /// </summary>
        /// <param name="pemFileConent">pem公钥内容</param>
        /// <returns>转换得到的RSAParamenters</returns>
        public static RSAParameters ConvertFromPemPublicKey(string pemFileConent)
        {
            if (string.IsNullOrEmpty(pemFileConent))
            {
                throw new ArgumentNullException("pemFileConent", "This arg cann't be empty.");
            }
            pemFileConent = pemFileConent.Replace("-----BEGIN PUBLIC KEY-----", "").Replace("-----END PUBLIC KEY-----", "").Replace("\n", "").Replace("\r", "");
            byte[] keyData = Convert.FromBase64String(pemFileConent);
            bool keySize1024 = (keyData.Length == 162);
            bool keySize2048 = (keyData.Length == 294);
            if (!( keySize1024 || keySize2048 ))
            {
                throw new ArgumentException("pem file content is incorrect, Only support the key size is 1024 or 2048");
            }
            byte[] pemModulus = (keySize1024? new byte[128] : new byte[256]);
            byte[] pemPublicExponent = new byte[3];
            Array.Copy(keyData, (keySize1024? 29:33), pemModulus, 0,(keySize1024? 128:256));
            Array.Copy(keyData, (keySize1024? 159:291), pemPublicExponent, 0, 3);
            RSAParameters para = new RSAParameters();
            para.Modulus = pemModulus;
            para.Exponent = pemPublicExponent;
            return para;
        }

        /// <summary>
        /// 将pem格式私钥(1024 or 2048)转换为RSAParameters
        /// </summary>
        /// <param name="pemFileConent">pem私钥内容</param>
        /// <returns>转换得到的RSAParamenters</returns>
        public static RSAParameters ConvertFromPemPrivateKey(string pemFileConent)
        {
            if (string.IsNullOrEmpty(pemFileConent))
            {
                throw new ArgumentNullException("pemFileConent", "This arg cann't be empty.");
            }
            pemFileConent = pemFileConent.Replace("-----BEGIN RSA PRIVATE KEY-----", "").Replace("-----END RSA PRIVATE KEY-----", "").Replace("\n", "").Replace("\r","");
            byte[] keyData = Convert.FromBase64String(pemFileConent);

            bool keySize1024 = (keyData.Length == 609 || keyData.Length == 610);
            bool keySize2048 = (keyData.Length == 1190 || keyData.Length == 1192);

            if (!(keySize1024 || keySize2048))
            {
                throw new ArgumentException("pem file content is incorrect, Only support the key size is 1024 or 2048");
            }

            int index = ( keySize1024 ? 11 : 12);
            byte[] pemModulus = ( keySize1024 ? new byte[128]:new byte[256]);
            Array.Copy(keyData, index, pemModulus, 0, pemModulus.Length);

            index += pemModulus.Length;
            index += 2;
            byte[] pemPublicExponent = new byte[3];
            Array.Copy(keyData, index, pemPublicExponent, 0, 3);

            index += 3;
            index += 4;
            if ((int)keyData[index] == 0)
            {
                index++;
            }
            byte[] pemPrivateExponent = (keySize1024 ? new byte[128] : new byte[256]);
            Array.Copy(keyData, index , pemPrivateExponent, 0, pemPrivateExponent.Length);

index += pemPrivateExponent.Le

补充：Web开发 , ASP.Net ,