您可以使用公共密钥加密技术将数据（在您的情况下为私钥）从一侧安全地发送到另一侧。双方都可以访问公钥，而只有一侧可以访问私钥。使用公钥加密数据时，使用私钥解密数据。可以通过这种方式加密的数据大小是有限的（通常只有128-256字节）。因此，通常该技术用于加密/解密另一个加密/解密实际数据的加密密钥（AES ...）。

class Program
{
    static void Main(string[] args)
    {
        // your data you want to securely send from B to A without revealing the content
        byte[] data = new byte[] { 1,2,3,4,5,6 };

        // side A
        System.Security.Cryptography.RSACryptoServiceProvider full_rsa = new System.Security.Cryptography.RSACryptoServiceProvider(1024);

        byte[] publickey = full_rsa.ExportCspBlob(false);

        // send the public key to B
        // send(publickey)...

        // side B
        //send encrypted data back to side A
        byte[] encrypteddata = EncryptData(publickey,data); 

        // side A
        // decrypt the data encryped by side B
        byte[] decrypteddata = DecryptData(full_rsa,encrypteddata); 

        // decrypteddata = 1,6
    }

    public static byte[] DecryptData(System.Security.Cryptography.RSACryptoServiceProvider full_rsa,byte[] data)
    {
        System.IO.BinaryReader br = new System.IO.BinaryReader(new System.IO.MemoryStream(data));
        int encryptedkeylength = br.ReadInt32();
        int aeskeylength = br.ReadInt32();
        int aesivlength = br.ReadInt32();
        byte[] encryptedaeskey = br.ReadBytes(encryptedkeylength);
        byte[] encrypteddata = br.ReadBytes( (int)(data.Length - br.BaseStream.Position));
        br.Close();

        byte[] decryptedkey = full_rsa.Decrypt(encryptedaeskey,false);

        br = new System.IO.BinaryReader(new System.IO.MemoryStream(decryptedkey));
        using (System.Security.Cryptography.Aes myAes = System.Security.Cryptography.Aes.Create())
        {
            byte[] aeskey = br.ReadBytes(aeskeylength);
            byte[] aesiv = br.ReadBytes(aesivlength);
            System.Security.Cryptography.ICryptoTransform decryptor = myAes.CreateDecryptor(aeskey,aesiv);

            using (System.IO.MemoryStream msDecrypt = new System.IO.MemoryStream())
            {
                using (System.Security.Cryptography.CryptoStream csEncrypt = new System.Security.Cryptography.CryptoStream(msDecrypt,decryptor,System.Security.Cryptography.CryptoStreamMode.Write))
                {
                    using (System.IO.BinaryWriter bw = new System.IO.BinaryWriter(csEncrypt))
                    {
                        bw.Write(encrypteddata);
                    }
                    return msDecrypt.ToArray();
                }
            }
        }
    }

    public static byte[] EncryptData(byte[] publickey,byte[] data)
    {
        using (System.Security.Cryptography.Aes myAes = System.Security.Cryptography.Aes.Create())
        {
            System.Security.Cryptography.ICryptoTransform encryptor = myAes.CreateEncryptor(myAes.Key,myAes.IV);

            using (System.IO.MemoryStream msEncrypt = new System.IO.MemoryStream())
            {
                using (System.Security.Cryptography.CryptoStream csEncrypt = new System.Security.Cryptography.CryptoStream(msEncrypt,encryptor,System.Security.Cryptography.CryptoStreamMode.Write))
                {
                    System.IO.MemoryStream headerms = new System.IO.MemoryStream();
                    System.IO.BinaryWriter headerbw = new System.IO.BinaryWriter(headerms);

                    using (System.IO.BinaryWriter bw = new System.IO.BinaryWriter(csEncrypt))
                    {
                        System.Security.Cryptography.RSACryptoServiceProvider public_key = new System.Security.Cryptography.RSACryptoServiceProvider(1024);
                        public_key.ImportCspBlob(publickey);

                        byte[] encryptedkey = public_key.Encrypt(Combine(myAes.Key,myAes.IV),false);
                        headerbw.Write(encryptedkey.Length);
                        headerbw.Write(myAes.Key.Length);
                        headerbw.Write(myAes.IV.Length);
                        headerbw.Write(encryptedkey);
                        headerbw.Flush();
                        bw.Write(data);
                    }                            

                    byte[] result = Combine(headerms.ToArray(),msEncrypt.ToArray());
                    headerbw.Close();
                    return result;
                }
            }
        }
    }

    static byte[] Combine(byte[] first,byte[] second)
    {
        byte[] ret = new byte[first.Length + second.Length];
        Buffer.BlockCopy(first,ret,first.Length);
        Buffer.BlockCopy(second,first.Length,second.Length);
        return ret;
    }
}