c# - ECDH Nodejs 和 C# key 交换

Question

我迷失了 self ，我需要帮助才能走上正确的方向:) 我有一个 Nodejs 服务器，它必须与用 C# 编写的服务器交换一些关键数据，所以在这种情况下，我希望我的数据以某种方式加密。我正在考虑 AES，为了安全地交换 key ，我想使用 ECDH，但我不知道如何使其正常工作...如果我的想法正确，我可以使我的 C#“allice”端像这样:

ECDiffieHellman alice = ECDiffieHellman.Create(ECCurve.NamedCurves.brainpoolP192t1);
var aliceKey = alice.PublicKey;
var ketyToExport = Convert.ToBase64String(aliceKey.ToByteArray());
//send ketyToExport to nodejs
//KEY FROM nodejs
var key1 = Convert.FromBase64String("BIzSJ1dmTXpSS8rqkVFISZ+vumhqXYMWfWoU5vB9GHhOtxxDInu/GZ92VJpqhrE3vw==").ToList();
var keyType = new byte[] { 0x45, 0x43, 0x4B, 0x31 };
var keyLength = new byte[] { 0x20, 0x00, 0x00, 0x00 };
key1.RemoveAt(0);
key1 = keyType.Concat(keyLength).Concat(key1).ToList();
byte[] bobKeyBytes = key1.ToArray();
//and I have a problem with that line bellow, I do not know how to make it work
var aliceSecret = alice.DeriveKeyMaterial(/*ECDiffieHellmanPublicKey bobKeyBytes*/);

nodejs“Bob”一侧是这样的:

const crypto = require("crypto");
const bob = crypto.createECDH('brainpoolP192t1')
const bobKey = bob.generateKeys('base64');
var bobLength = Buffer.from(bobKey, 'base64').length;
//send bobkey to c#
//recive alicekey
var tmp = "RUNLUBgAAAAR9C7kO2o+vxNT/UBvvEuJHNdI8NfU4fUxUT431ER1q3kJbeUVHepoG5SWUM2NHj8="
var aliceKeyBuffer = Buffer.from(tmp, 'base64');
var aliceKey = Buffer.alloc(bobLength)
aliceKeyBuffer.copy(aliceKey, 1, 8);
aliceKey[0] = 4;
bob.computeSecret(aliceKey);
//create aes 
//get mesage and iv ...

好吧，我已经对所有这些进行了一些调整，但现在我不知道该怎么处理这条线如何使其工作...... var aliceSecret = alice.DeriveKeyMaterial(/*ECDiffieHellmanPublicKey bobKeyBytes*/);

#大编辑 我在 ECDiffieHellmanPublicKey from ByteArray (using ECDiffieHellman NamedCurves) 获得了帮助 现在我有另一个问题-_- 我的 Node js 代码与上面没有改变，但 C# 看起来像:

using (ECDiffieHellman alice = ECDiffieHellman.Create(ECCurve.NamedCurves.brainpoolP256r1))
{
    var alicePublicKey = Convert.ToBase64String(alice.PublicKey.ToByteArray());
    //NODEJS brainpoolP256r1 publickey 
    var key1 = Convert.FromBase64String("BASsbkule53ARqlMBA8hYysyyoRi3xGxGnSzIJ2fS5FlLniQD/zYiiGUVydmO/BBkQwVTUo5f4OMCxVNtQ/LuMQ=");
    byte[] keyX = new byte[key1.Length / 2];
    byte[] keyY = new byte[keyX.Length];
    Buffer.BlockCopy(key1, 1, keyX, 0, keyX.Length);
    Buffer.BlockCopy(key1, 1 + keyX.Length, keyY, 0, keyY.Length);
    ECParameters parameters = new ECParameters
    {
        Curve = ECCurve.NamedCurves.brainpoolP256r1,
        Q =
        {
            X = keyX,
            Y = keyY,
        },
    };
    byte[] derivedKey;
    using (ECDiffieHellman bob = ECDiffieHellman.Create(parameters))
    using (ECDiffieHellmanPublicKey bobPublic = bob.PublicKey)
    {
        derivedKey = alice.DeriveKeyFromHash(bobPublic, HashAlgorithmName.SHA256);
    }
    var aliceKey = Convert.ToBase64String(derivedKey);
    byte[] encryptedMessage = null;
    byte[] iv = null;
    // Send(aliceKey, "Secret message", out encryptedMessage, out iv);
}

它正在工作，但它给了我不同的 key ...... 共 bob.computeSecret(aliceKey)我得到了iIoH9aJoWf3666QQ6X+kj4iUKrk9j+hbRuXbhgs7YzM= 并出 alice.DeriveKeyFromHash(bobPublic, HashAlgorithmName.SHA256); 我得到了wJ7O4Hm2Jxs1FcLx6KaMmENvqdTQJPZ/YNSs1+MQDOQ= 如果我的想法正确的话，它们应该是平等的。难道是我想错了？

#编辑完成!!

所以在 js 文件末尾添加这段代码给了我我所需要的。

const hash = crypto.createHash('sha256');
var tt = bob.computeSecret(aliceKey);
hash.update(tt);
console.log(hash.digest('base64'));

Answer 1

##解决方案##

C#

class Program
{
    static void Main(string[] args)
    {
        using (ECDiffieHellman alice = ECDiffieHellman.Create(ECCurve.NamedCurves.brainpoolP256r1))
        {
            var alicePublicKey = Convert.ToBase64String(alice.PublicKey.ToByteArray());
            //send alicePublicKey
            var nodejsKey = ""; //NODEJS brainpoolP256r1 publickey  base64
            byte[] nodejsKeyBytes= Convert.FromBase64String(nodejsKey);

            var aliceKey = Convert.ToBase64String(getDeriveKey(nodejsKeyBytes,alice));
            byte[] encryptedMessage = null;
            byte[] iv = null;
            // Send(aliceKey, "Secret message", out encryptedMessage, out iv);
        }
    }
    static byte[] getDeriveKey(byte[] key1, ECDiffieHellman alice)
    {
        byte[] keyX = new byte[key1.Length / 2];
        byte[] keyY = new byte[keyX.Length];
        Buffer.BlockCopy(key1, 1, keyX, 0, keyX.Length);
        Buffer.BlockCopy(key1, 1 + keyX.Length, keyY, 0, keyY.Length);
        ECParameters parameters = new ECParameters
        {
            Curve = ECCurve.NamedCurves.brainpoolP256r1,
            Q =
            {
                X = keyX,
                Y = keyY,
            },
        };
        byte[] derivedKey;
        using (ECDiffieHellman bob = ECDiffieHellman.Create(parameters))
        using (ECDiffieHellmanPublicKey bobPublic = bob.PublicKey)
        {
            return derivedKey = alice.DeriveKeyFromHash(bobPublic, HashAlgorithmName.SHA256);
        }
    }
}

NODEJS

const crypto = require("crypto");
const bob = crypto.createECDH('brainpoolP256r1')
bob.generateKeys();
const bobKey = bob.getPublicKey('base64');
var bobLength = Buffer.from(bobKey, 'base64').length;
//send bobkey to c#
//recive alicekey

var alicePublicKey = "RUNLUCAAAAB/xP7JhSIhYIYAijyC2zHu7obB5CwfK/ynQPxcRAIhBI6OLRRcHyPo61AhfSZN3qA2vGDfWO2mrdWWvqqhVaDf";
var aliceKeyBuffer = Buffer.from(alicePublicKey, 'base64');
var aliceKey = Buffer.alloc(bobLength)
aliceKeyBuffer.copy(aliceKey, 1, 8);
aliceKey[0] = 4;
const hash = crypto.createHash('sha256');
var tt = bob.computeSecret(aliceKey);
var bobSecretKey = hash.update(tt).digest('base64');

非常感谢 @bartonjs和 @Maarten Bodewes