<經驗雜談>C#對CA證書加密解密的簡單介紹

最近做項目接觸了一些關於用CA證書加密解密的知識，現在分享一下，加密主要分為對稱加密和非對稱加密以及單項加密這三種，CA是一個權威的第三方認證機構，CA加密有公鑰和私鑰之分。

以下是C#讀取證書文件進行加密解密的Code，供各位參考

 CA 加密：

public static string CAEncryption(string xml)
        {
            X509Certificate2 pubcrt =new X509Certificate2(AppDomain.CurrentDomain.BaseDirectory + BaseConfig.CaPubkey);
            return Core.CaUtilHelper.Encrypt(xml, pubcrt);
        }


public static String Encrypt(String plaintext, X509Certificate2 pubcrt)
        {
            X509Certificate2 _X509Certificate2 = pubcrt;
            using (RSACryptoServiceProvider RSACryptography = _X509Certificate2.PublicKey.Key as RSACryptoServiceProvider)
            {
                Byte[] PlaintextData = Encoding.UTF8.GetBytes(plaintext);
                int MaxBlockSize = RSACryptography.KeySize / 8 - 11;    //加密塊最大長度限制  
                if (PlaintextData.Length <= MaxBlockSize)
                    return Convert.ToBase64String(RSACryptography.Encrypt(PlaintextData, false));
                using (MemoryStream PlaiStream = new MemoryStream(PlaintextData))
                using (MemoryStream CrypStream = new MemoryStream())
                {
                    Byte[] Buffer = new Byte[MaxBlockSize];
                    int BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);
                    while (BlockSize > 0)
                    {
                        Byte[] ToEncrypt = new Byte[BlockSize];
                        Array.Copy(Buffer, 0, ToEncrypt, 0, BlockSize);
                        Byte[] Cryptograph = RSACryptography.Encrypt(ToEncrypt, false);
                        CrypStream.Write(Cryptograph, 0, Cryptograph.Length);
                        BlockSize = PlaiStream.Read(Buffer, 0, MaxBlockSize);
                    }
                    return Convert.ToBase64String(CrypStream.ToArray(), Base64FormattingOptions.None);
                }
            }
        }

CA 解密：

public static string CADecrypt(string content)
        {
            X509Certificate2 prvcrt = new X509Certificate2(AppDomain.CurrentDomain.BaseDirectory + BaseConfig.CaPrvkey,BaseConfig.CaPwd, X509KeyStorageFlags.Exportable);
            return Core.CaUtilHelper.Decrypt(content, prvcrt);
        }


public static String Decrypt(String ciphertext, X509Certificate2 prvpfx)
        {
            X509Certificate2 _X509Certificate2 = prvpfx;
            using (RSACryptoServiceProvider RSACryptography = _X509Certificate2.PrivateKey as RSACryptoServiceProvider)
            {
                Byte[] CiphertextData = Convert.FromBase64String(ciphertext);
                int MaxBlockSize = RSACryptography.KeySize / 8; //解密塊最大長度限制  
                if (CiphertextData.Length <= MaxBlockSize)
                    return Encoding.UTF8.GetString(RSACryptography.Decrypt(CiphertextData, false));
                using (MemoryStream CrypStream = new MemoryStream(CiphertextData))
                using (MemoryStream PlaiStream = new MemoryStream())
                {
                    Byte[] Buffer = new Byte[MaxBlockSize];
                    int BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
                    while (BlockSize > 0)
                    {
                        Byte[] ToDecrypt = new Byte[BlockSize];
                        Array.Copy(Buffer, 0, ToDecrypt, 0, BlockSize);
                        Byte[] Plaintext = RSACryptography.Decrypt(ToDecrypt, false);
                        PlaiStream.Write(Plaintext, 0, Plaintext.Length);
                        BlockSize = CrypStream.Read(Buffer, 0, MaxBlockSize);
                    }
                    return Encoding.UTF8.GetString(PlaiStream.ToArray());
                }
            }
        }