Question

我迷失了自我，我需要帮助才能朝着正确的方向发展：) 我有nodejs服务器，它必须与用C＃编写的服务器交换一些关键数据，因此在这种情况下，我希望以某种方式对我的数据进行加密。我在考虑AES，并且为了安全地交换密钥，我想使用ECDH，但是我不知道如何使其正常工作...如果我想的正确，我可以像这样使C＃的“ allice”面：

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*/);

而nodejs的“鲍勃”面像这样：

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，但是现在我不知道该行怎么做才能使其正常工作... var aliceSecret = alice.DeriveKeyMaterial(/*ECDiffieHellmanPublicKey bobKeyBytes*/);

#BIG EDIT 我在ECDiffieHellmanPublicKey from ByteArray (using ECDiffieHellman NamedCurves)中获得了帮助现在我有另一个问题-_- 我的节点js代码没有从上面改变，但是c＃看起来像这样：

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，但是它给了我不同的密钥... 从bob.computeSecret(aliceKey)中我得到了iIoH9aJoWf3666QQ6X+kj4iUKrk9j+hbRuXbhgs7YzM= 在alice.DeriveKeyFromHash(bobPublic, HashAlgorithmName.SHA256);中我得到了wJ7O4Hm2Jxs1FcLx6KaMmENvqdTQJPZ/YNSs1+MQDOQ= 如果我在想的正确的话，他们应该是平等的。我在想错吗？

#EDIT完成!!

因此，将这段代码添加到js文件的末尾可以满足我的需求。

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

Answer 1

## SOLUTION ##

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

Answer 2

以上答案对我有很大帮助。我正在使用secp521r1 / nistP521在NodeJS和C＃中进行密钥生成。就我而言，调用alice.PublicKey.ToByteArray()会导致异常：

Unhandled exception. System.PlatformNotSupportedException: Operation is not supported on this platform.
   at System.Security.Cryptography.ECDiffieHellmanImplementation.ECDiffieHellmanSecurityTransforms.ECDiffieHellmanSecurityTransformsPublicKey.ToByteArray()

根据与dotnet运行时团队here一起记录的问题：

ECDiffieHellmanPublicKey.ToByteArray（）没有（标准）定义的导出格式。 ECDiffieHellmanPublicKeyCng使用的版本特定于Windows，仅适用于NIST P-256（secp256r1），NIST P-384（secp384r1）和NIST P-521（secp521r1）。

要创建键的副本，应使用ExportParameters（）方法获取丰富的ECParameters对象；然后可以通过ECDiffieHellman.Create（ECParameters）发送该消息，并读取该对象的PublicKey属性以获取ECDiffieHellmanPublicKey的第二个实例。

假设我将Alice中的X和Y发送给Bob（我使用hex而不是base64），则在NodeJS端获得相同共享密钥的相应过程如下所示：

// Alice's public key X, Y coordinates from DotNet Core
const aliceHexX = '00248F624728B17196B22005742C13D80D3DFF75BCA74AF865195E5A29F41C013653B0931BC544245402EDD7922F38692F38DCCF780CF1A9E27D3CFB5E09E53883C0';
const aliceHexY = '0043517F3B2EF33ED70EFA2BC4163E9B99558A7C2ECB7C659A12EA4024633CFA8B9FC997F0A42D30759B4280FDADC13A67A3E7BB0227047C907FAAE92E7716E8A10D';

const alicePublicKeyXBytes = Buffer.from(aliceHexX, 'hex');
const alicePublicKeyYBytes = Buffer.from(aliceHexY, 'hex');
const alicePublicKey = Buffer.concat([Buffer.from([0x04]), alicePublicKeyXBytes, alicePublicKeyYBytes])
const bobSecret = bob.computeSecret(alicePublicKey);

const hash = crypto.createHash('sha256');
hash.update(bobSecret);
const sharedSecret = hash.digest('hex');
console.log(`Shared Secret: ${sharedSecret.toString('hex')}`);

ECDH nodejs和C＃密钥交换

2 个答案: