5

我有一个非常小的节点脚本来创建公钥/私钥有没有办法在客户端执行它而无需浏览孔加密模块？

var crypto    = require('crypto');

var userCurve = crypto.createECDH('prime256v1');
var userPublicKey = userCurve.generateKeys()
var userPrivateKey = userCurve.getPrivateKey();

到目前为止，我已经尝试过：

// https://github.com/diafygi/webcrypto-examples#ecdh---generatekey
window.crypto.subtle.generateKey(
    {
        name: "ECDH",
        namedCurve: "P-256", //can be "P-256", "P-384", or "P-521"
    },
    true, //whether the key is extractable (i.e. can be used in exportKey)
    ["deriveKey", "deriveBits"] //can be any combination of "deriveKey" and "deriveBits"
)
.then(function(key){
    //returns a keypair object
    console.log(key);
    console.log(key.publicKey);
    console.log(key.privateKey);
})
.catch(function(err){
    console.error(err);
});

但是当我记录它时它看起来不像节点版本

4

1 回答 1

22

让我们做一个完整的椭圆曲线 Diffie-Hellman (ECDH) 交换来建立两方之间的共享秘密。Alice 使用 Node.js，而 Bob 坐在他的浏览器（Chrome 或 Firefox 的最新版本）前。（无需浏览任何东西。）

(1) Alice 生成私钥和公钥。

const crypto = require('crypto');

const alice = crypto.createECDH('prime256v1');
alice.generateKeys()

const alicePublicKey = alice.getPublicKey('hex')
const alicePrivateKey = alice.getPrivateKey('hex')

console.log(`publicKey: ${alicePublicKey}`)
console.log(`privateKey: ${alicePrivateKey}`)

示例输出：

publicKey: 043a3770a8068738ded16c9409e1a6fbf6dde2360ac5b3fd3e5bb8d9fd6adaed6ea83ff5153f58ae13098e86da89df1beb14ef46388d3df76e8fe2ee0ff9e926d5
privateKey: 03ce9cb317c8761699f174943dc9b2d2b7991515b48216a4c677fcf5ee879f2c

(2) Alice 将她的公钥发送给 Bob ( 043a3770...)。Bob 编写了一些帮助程序来将十六进制字符串转换为十六进制字符串Uint8Arrays并将缓冲区转换为十六进制字符串。

const hex2Arr = str => {
    if (!str) {
        return new Uint8Array()
    }
    const arr = []
    for (let i = 0, len = str.length; i < len; i+=2) {
        arr.push(parseInt(str.substr(i, 2), 16))
    }
    return new Uint8Array(arr)
}

const buf2Hex = buf => {
    return Array.from(new Uint8Array(buf))
        .map(x => ('00' + x.toString(16)).slice(-2))
        .join('')
}

(3) Bob 收到 Alice 的密钥并计算共享密钥

  • 他生成自己的私钥和公钥
  • 他导出他的公钥并将其发送给 Alice
  • 他导入 Alice 的公钥

  • 他使用他的私钥和 Alice 的公钥计算共享秘密

    // Alice's public key (received over an [insecure] connection)
const alicePublicKeyHex = '043a3770a8068738ded16c9409e1a6fbf6dde2360ac5b3fd3e5bb8d9fd6adaed6ea83ff5153f58ae13098e86da89df1beb14ef46388d3df76e8fe2ee0ff9e926d5'
const alicePublicKey = hex2Arr(alicePublicKeyHex)
console.log(`Alice's publicKey: ${alicePublicKeyHex}`)

let bob = null

// generate Bob's private and public key
window.crypto.subtle.generateKey(
    {
        name: 'ECDH',
        namedCurve: 'P-256'
    },
    false, // no need to make Bob's private key exportable
    ['deriveKey', 'deriveBits'])
    .then(bobKey => {
        bob = bobKey
        // export Bob's public key
        return window.crypto.subtle.exportKey(
            'raw', bobKey.publicKey
        )
    })
    .then(bobPublicKeyExported => {
        const bobPublicKeyHex = buf2Hex(bobPublicKeyExported)
        // display and send Bob's public key to Alice
        console.log(`Bob's publicKey: ${bobPublicKeyHex}`)

        // import Alice's public key
        return window.crypto.subtle.importKey(
            'raw',
            alicePublicKey,
            {
                name: 'ECDH',
                namedCurve: 'P-256'
            },
            true,
            [])
    })
    .then(aliceKeyImported => {
        // use Alice's imported public key and
        // Bob's private key to compute the shared secret
        return window.crypto.subtle.deriveBits(
            {
                name: 'ECDH',
                namedCurve: 'P-256',
                public: aliceKeyImported
            },
            bob.privateKey,
            256)
    })
    .then(sharedSecret => {
        const sharedSecretHex = buf2Hex(sharedSecret)
        console.log(`sharedSecret: ${sharedSecretHex}`)
    })
    .catch(err => {
        console.log(err)
    })

示例输出：

Alice's publicKey: 043a3770a8068738ded16c9409e1a6fbf6dde2360ac5b3fd3e5bb8d9fd6adaed6ea83ff5153f58ae13098e86da89df1beb14ef46388d3df76e8fe2ee0ff9e926d5
Bob's publicKey: 04aeceba6ae783c9b705833c2fa8822281f47f6f36bc867e4d398fa7a744d4fc63a010cbce1e6c9ac8858ad376a24ee8551615560f01c8bb63c86335c046b18962
sharedSecret: c26c9f370f001a947d7fec4dc9282d3e9ea718e1de487eb4f6fa7d6f0a311b97

(4) Alice 收到 Bob 的公钥 ( 04aece...)。她也计算共享秘密。

const crypto = require('crypto')
const alice = crypto.createECDH('prime256v1')

// Alice's privateKey (generated previously)
const alicePrivateKey = '937cdd11062b612ff3cb3e4a3c183254b9728b4c8c3a64de799ed196b672734b'

// Bob's publicKey transmitted to Alice
const bobPublicKey = '04aeceba6ae783c9b705833c2fa8822281f47f6f36bc867e4d398fa7a744d4fc63a010cbce1e6c9ac8858ad376a24ee8551615560f01c8bb63c86335c046b18962'

// set Alice's private key (not needed if continuing from (1))
alice.setPrivateKey(alicePrivateKey, 'hex')

const sharedSecret = alice.computeSecret(bobPublicKey, 'hex', 'hex')
console.log(`sharedSecret: ${sharedSecret}`)

示例输出：

sharedSecret: c26c9f370f001a947d7fec4dc9282d3e9ea718e1de487eb4f6fa7d6f0a311b97

秘密是共享的（相同的）。

(5) 共享密钥通常用于派生对称密钥，用于加密 Alice 和 Bob 之间的消息（他们从此愉快地通信）。

评论：

  • 通常不需要显示或导出私钥。Alice 通常会从步骤 (1) 继续计算共享秘密（并省略alice.setPrivateKey(alicePrivateKey, 'hex')）。

  • 由于共享密钥最常用于派生对称密钥，因此window.crypto.subtle.deriveKey可以deriveBits省略。deriveBits在这里用来说明 Alice 和 Bob 确实就共享秘密达成了一致。

于 2018-01-26T10:45:45.487 回答