AesCng持久化密钥导出/导入：导入失败，出现CryptographicException：提供的句柄无效。 [英] AesCng persisted key export/import: Import fails with CryptographicException: The supplied handle is invalid.

问题描述

我可以创建持久的AES密钥

I can create the persisted AES key

        public static bool CreateContainer(string name)
        {
            if (CngKey.Exists(name))
            {
                return false;
            }

            CngKeyCreationParameters keyCreationParameters = new CngKeyCreationParameters()
            {
                ExportPolicy = CngExportPolicies.AllowPlaintextExport,
                KeyCreationOptions = CngKeyCreationOptions.OverwriteExistingKey
            };
            CngKey cngKey = CngKey.Create(new CngAlgorithm("AES"), name, keyCreationParameters);
            cngKey.Dispose();
            return true;
        }

然后用它来加密/解密

        public static byte[] Encrypt(string keyContainerName, byte[] clearText, byte[] iv)
        {
            AesCng aesCng = null;
            ICryptoTransform crypto = null;
            byte[] cipher = null;
            try
            {
                aesCng = new AesCng(keyContainerName);
                aesCng.IV = (iv == null ? new byte[aesCng.IV.Length] : iv);
                crypto = aesCng.CreateEncryptor();
                cipher = crypto.TransformFinalBlock(clearText, 0, clearText.Length);
            }
            finally
            {
                if (crypto != null)
                {
                    crypto.Dispose();
                }
                if (aesCng != null)
                {
                    aesCng.Clear();
                    aesCng.Dispose();
                }
            }
            return cipher;
        }

        public static byte[] Decrypt(string keyContainerName, byte[] cipher, byte[] iv)
        {
            AesCng aesCng = null;
            ICryptoTransform crypto = null;
            byte[] clearText = null;
            try
            {
                aesCng = new AesCng(keyContainerName);
                aesCng.IV = (iv == null ? new byte[aesCng.IV.Length] : iv);
                crypto = aesCng.CreateDecryptor();
                clearText = crypto.TransformFinalBlock(cipher, 0, cipher.Length);
            }
            finally
            {
                if (crypto != null)
                {
                    crypto.Dispose();
                }
                if (aesCng != null)
                {
                    aesCng.Clear();
                    aesCng.Dispose();
                }
            }
            return clearText;
        }

我可以导出密钥

I am able to export the key

        public static bool ExportKey(string name, out byte[] blob)
        {
            blob = null;
            if (!CngKey.Exists(name))
            {
                return false;
            }

            CngKey cngKey = CngKey.Open(name);
            blob = cngKey.Export(CngKeyBlobFormat.OpaqueTransportBlob);
            cngKey.Dispose();
            return true;
        }

但是，当我尝试导入blob时，我收到一个CryptographicException：提供的句柄无效。

However, when I try to import the blob, I get a CryptographicException: The supplied handle is invalid.

        public static void ImportKey(string name, byte[] blob)
        {
            CngKey cngKey = CngKey.Import(blob, CngKeyBlobFormat.OpaqueTransportBlob);
            cngKey.Dispose();
        }

我无法解释失败原因。

任何人都可以解决问题在这？谢谢。

Can anyone shed some light on this? Thanks.

推荐答案

您好L_E_R，

Hi L_E_R,

感谢您在此发帖。

为您服务问题，在加密操作期间发生错误时抛出CryptographicException。我猜你在AES和CNG会话之间使用了错误的格式。

For your question, CryptographicException is thrown when an error occurs during a cryptographic operation. I guess you use the wrong format between AES and CNG conversation.

这是一个关于CNG导入密钥的代码示例供你参考。

Here is a code sample about CNG to import key for your reference.

using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;
using System;

namespace SecureTranferTest
{
    class Program
    {
        /// <summary>
        /// Anli's private key
        /// </summary>
        public static System.Security.Cryptography.CngKey anlikey = null;

        //Anli's public key
        public static byte[] anlipulicKey = null;
        //bob's private key
        public static System.Security.Cryptography.CngKey bobkey = null;
        public static byte[] bobpulicKey = null;

        static void Main(string[] args)
        {
            CreateKey();
            AnliSendMessage("Nice day");//Anli send message to bob
            AnliSendMessage("hello");//Anli send message to bob
            Console.ReadKey();
        }

        public static void CreateKey()
        {

            
            anlikey = CngKey.Create(CngAlgorithm.ECDiffieHellmanP256);
           
            anlipulicKey = anlikey.Export(CngKeyBlobFormat.EccPublicBlob);
            
            bobkey = CngKey.Create(CngAlgorithm.ECDiffieHellmanP256);
            
            bobpulicKey = bobkey.Export(CngKeyBlobFormat.EccPublicBlob);

        }

        public static void AnliSendMessage(string message)
        {
            byte[] rowData = Encoding.UTF8.GetBytes(message); 
          
            using (ECDiffieHellmanCng cng = new ECDiffieHellmanCng(anlikey))
            {
              
                using (CngKey bobkey = CngKey.Import(bobpulicKey, CngKeyBlobFormat.EccPublicBlob))
                {
                   
                    var sumKey = cng.DeriveKeyMaterial(bobkey);
                  
                    using (var aes = new AesCryptoServiceProvider())
                    {
                        aes.Key = sumKey; 
                        aes.GenerateIV();
                      
                        using (ICryptoTransform encryptor = aes.CreateEncryptor())
                        {
                            using (MemoryStream ms = new MemoryStream())
                            {
                              
                                var cs = new CryptoStream(ms, encryptor, CryptoStreamMode.Write);
                           
                                ms.Write(aes.IV, 0, aes.IV.Length);
                           
                                cs.Write(rowData, 0, rowData.Length);
                                cs.Close();
                                var data = ms.ToArray();
                               
                                Console.WriteLine("Anli send message to bob");
                                BobReceivesData(data);
                            }
                            aes.Clear();
                        }
                    }
                }
            }
        }

       
        public static void BobReceivesData(byte[] data)
        {
            Console.WriteLine("Get the message, to encrypt");
            byte[] rowData = null;
            
            using (var aes = new AesCryptoServiceProvider())
            {
                var ivlength = aes.BlockSize >> 3;
                byte[] ivdata = new byte[ivlength];
                Array.Copy(data, ivdata, ivlength);
               
                using (ECDiffieHellmanCng cng = new ECDiffieHellmanCng(bobkey))
                {
                    
                    using (CngKey anikey = CngKey.Import(anlipulicKey, CngKeyBlobFormat.EccPublicBlob))
                    {
                      
                        var sumKey = cng.DeriveKeyMaterial(anikey);
                        aes.Key = sumKey;
                        aes.IV = ivdata;
                        using (ICryptoTransform decryptor = aes.CreateDecryptor())
                        using (MemoryStream me = new MemoryStream())
                        {
                            
                            var cs = new CryptoStream(me, decryptor, CryptoStreamMode.Write);
                            cs.Write(data, ivlength, data.Length - ivlength);
                            cs.Close();
                            rowData = me.ToArray();
                            Console.WriteLine("Decrypt successfully!");
                            Console.WriteLine(Encoding.UTF8.GetString(rowData));
                        }
                    }
                }
            }



        }


    }
}

最好的问候，

Wendy

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