SpringBoot集成ECDH密鑰交換的方法

更新時間：2025年01月03日 09:19:43 作者：code2roc

ECDH密鑰交換算法通過橢圓曲線和Diffie-Hellman方法生成共享密鑰,用于前端和后端之間的AES加密通信,前端使用elliptic.js生成密鑰對,后端使用crypto-js.min.js進行AES加密,本文給大家介紹SpringBoot集成ECDH密鑰交換的相關知識,感興趣的朋友一起看看吧

簡介

對稱加解密算法都需要一把秘鑰，但是很多情況下，互聯(lián)網(wǎng)環(huán)境不適合傳輸這把對稱密碼，有密鑰泄露的風險，為了解決這個問題ECDH密鑰交換應運而生

EC：Elliptic Curve——橢圓曲線，生成密鑰的方法

DH：Diffie-Hellman Key Exchange——交換密鑰的方法

設計

數(shù)據(jù)傳輸?shù)膬煞椒斩耍⊿erver）和客戶端（Client）

服務端生成密鑰對Server-Public和Servier-Private

客戶端生成密鑰對Client-Public和Client-Private

客戶端獲取服務端的公鑰和客戶端的私鑰進行計算CaculateKey(Server-Public，Client-Private)出共享密鑰ShareKey1

服務端獲取客戶端的公鑰和服務端的私鑰進行計算CaculateKey(Client-Public，Server-Private)出共享密鑰ShareKey2

ShareKey1和ShareKey2必定一致，ShareKey就是雙方傳輸數(shù)據(jù)進行AES加密時的密鑰

實現(xiàn)

生成密鑰對

后端

    public static ECDHKeyInfo generateKeyInfo(){
        ECDHKeyInfo keyInfo = new ECDHKeyInfo();
        try{
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("EC");
            ECGenParameterSpec ecSpec = new ECGenParameterSpec("secp256r1");
            keyPairGenerator.initialize(ecSpec, new SecureRandom());
            KeyPair kp = keyPairGenerator.generateKeyPair();
            ECPublicKey ecPublicKey = (ECPublicKey) kp.getPublic();
            ECPrivateKey ecPrivateKey = (ECPrivateKey) kp.getPrivate();
            // 獲取公鑰點的x和y坐標
            BigInteger x = ecPublicKey.getW().getAffineX();
            BigInteger y = ecPublicKey.getW().getAffineY();
            // 將x和y坐標轉(zhuǎn)換為十六進制字符串
            String xHex = x.toString(16);
            String yHex = y.toString(16);
            String publicKey = xHex + "|" + yHex;
            String privateKey = Base64.getEncoder().encodeToString(ecPrivateKey.getEncoded());
            keyInfo.setPublicKey(publicKey);
            keyInfo.setPrivateKey(privateKey);
        }catch (Exception e){
            e.printStackTrace();
        }
        return keyInfo;
    }
    public static class ECDHKeyInfo{
        private String publicKey;
        private String privateKey;
        public String getPublicKey() {
            return publicKey;
        }
        public void setPublicKey(String publicKey) {
            this.publicKey = publicKey;
        }
        public String getPrivateKey() {
            return privateKey;
        }
        public void setPrivateKey(String privateKey) {
            this.privateKey = privateKey;
        }
    }

前端

引入elliptic.js（https://cdn.bootcdn.net/ajax/libs/elliptic/6.5.6/elliptic.js）

    const EC = elliptic.ec;
    const ec = new EC('p256'); // P-256曲線
    // 生成密鑰對
    const keyPair = ec.genKeyPair();
	const publicKey = keyPair.getPublic().getX().toString('hex') + "|" + keyPair.getPublic().getY().toString('hex');

共享密鑰計算

后端

    public static String caculateShareKey(String serverPrivateKey,String receivePublicKey){
        String shareKey = "";
        try{
            // 1. 后端私鑰 Base64 字符串
            // 2. 從 Base64 恢復后端私鑰
            ECPrivateKey privKey = loadPrivateKeyFromBase64(serverPrivateKey);
            // 3. 前端傳遞的公鑰坐標 (x 和 y 坐標，假設為十六進制字符串)
            // 假設這是從前端接收到的公鑰的 x 和 y 坐標
            String xHex = receivePublicKey.split("\\|")[0];  // 用前端傳遞的 x 坐標替換
            String yHex = receivePublicKey.split("\\|")[1];  // 用前端傳遞的 y 坐標替換
            // 4. 將 x 和 y 轉(zhuǎn)換為 BigInteger
            BigInteger x = new BigInteger(xHex, 16);
            BigInteger y = new BigInteger(yHex, 16);
            // 5. 創(chuàng)建 ECPoint 對象 (公鑰坐標)
            ECPoint ecPoint = new ECPoint(x, y);
            // 6. 獲取 EC 參數(shù)（例如 secp256r1）
            ECParameterSpec ecSpec = getECParameterSpec();
            // 7. 恢復公鑰
            ECPublicKey pubKey = recoverPublicKey(ecPoint, ecSpec);
            // 8. 使用 ECDH 計算共享密鑰
            byte[] sharedSecret = calculateSharedSecret(privKey, pubKey);
            // 9. 打印共享密鑰
            shareKey = bytesToHex(sharedSecret);
        }catch (Exception e){
            e.printStackTrace();
        }
        return shareKey;
    }
    // 從 Base64 加載 ECPrivateKey
    private static ECPrivateKey loadPrivateKeyFromBase64(String privateKeyBase64) throws Exception {
        byte[] decodedKey = Base64.getDecoder().decode(privateKeyBase64);
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(decodedKey);
        KeyFactory keyFactory = KeyFactory.getInstance("EC");
        return (ECPrivateKey) keyFactory.generatePrivate(keySpec);
    }
    // 獲取 EC 參數(shù)（例如 secp256r1）
    private static ECParameterSpec getECParameterSpec() throws Exception {
        // 手動指定 EC 曲線（例如 secp256r1）
        AlgorithmParameters params = AlgorithmParameters.getInstance("EC");
        params.init(new ECGenParameterSpec("secp256r1"));  // 使用標準的 P-256 曲線
        return params.getParameterSpec(ECParameterSpec.class);
    }
    // 恢復公鑰
    private static ECPublicKey recoverPublicKey(ECPoint ecPoint, ECParameterSpec ecSpec) throws Exception {
        ECPublicKeySpec pubKeySpec = new ECPublicKeySpec(ecPoint, ecSpec);
        KeyFactory keyFactory = KeyFactory.getInstance("EC");
        return (ECPublicKey) keyFactory.generatePublic(pubKeySpec);
    }
    // 使用 ECDH 計算共享密鑰
    private static byte[] calculateSharedSecret(ECPrivateKey privKey, ECPublicKey pubKey) throws Exception {
        KeyAgreement keyAgreement = KeyAgreement.getInstance("ECDH");
        keyAgreement.init(privKey);
        keyAgreement.doPhase(pubKey, true);
        return keyAgreement.generateSecret();
    }
    // 將字節(jié)數(shù)組轉(zhuǎn)換為十六進制字符串
    private static String bytesToHex(byte[] bytes) {
        StringBuilder hexString = new StringBuilder();
        for (byte b : bytes) {
            hexString.append(String.format("%02x", b));
        }
        return hexString.toString();
    }

前端

    var keyArray = serverPublicPointKey.split("|")
    const otherKey = ec.keyFromPublic({ x: keyArray[0], y: keyArray[1] }, 'hex');
    const sharedSecret = keyPair.derive(otherKey.getPublic());

AES加密

后端

    public static String encryptData(String data,String shareKey){
        String result = "";
        try{
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] aesKey = digest.digest(shareKey.getBytes());  // 獲取 256 位密鑰
            SecretKey key = new SecretKeySpec(aesKey, "AES");
            byte[] resultData = encrypt(data,key);
            result = Base64.getEncoder().encodeToString(resultData);
        }catch (Exception e){
            e.printStackTrace();
        }
        return result;
    }
    public static String decryptData(String data,String shareKey){
        String result = "";
        try{
            MessageDigest digest = MessageDigest.getInstance("SHA-256");
            byte[] aesKey = digest.digest(shareKey.getBytes());  // 獲取 256 位密鑰
            SecretKey key = new SecretKeySpec(aesKey, "AES");
            byte[] resultData = decrypt(Base64.getDecoder().decode(data),key);
            result = new String(resultData);
        }catch (Exception e){
            e.printStackTrace();
        }
        return result;
    }
    private static final String KEY_ALGORITHM = "AES";
    private static final String CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding";
    private static final String IV = "0102030405060708"; // 16 bytes key
    // 使用AES密鑰加密數(shù)據(jù)
    private static byte[] encrypt(String plaintext, SecretKey aesKey) throws Exception {
        SecretKeySpec keySpec = new SecretKeySpec(aesKey.getEncoded(), KEY_ALGORITHM);
        IvParameterSpec iv = new IvParameterSpec(IV.getBytes());
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, keySpec, iv);
        byte[] encrypted = cipher.doFinal(plaintext.getBytes());
        return encrypted;
    }
    // 使用AES密鑰解密數(shù)據(jù)
    private static byte[] decrypt(byte[] encryptedData, SecretKey aesKey) throws Exception {
        SecretKeySpec keySpec = new SecretKeySpec(aesKey.getEncoded(), KEY_ALGORITHM);
        IvParameterSpec iv = new IvParameterSpec(IV.getBytes());
        Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, keySpec, iv);
        byte[] original = cipher.doFinal(encryptedData);
        return original;
    }

前端

引入crypto-js.min.js（https://cdnjs.cloudflare.com/ajax/libs/crypto-js/4.1.1/crypto-js.min.js）

function encryptByECDH(message, shareKey) {
    const aesKey = CryptoJS.SHA256(shareKey);
    const key = CryptoJS.enc.Base64.parse(aesKey.toString(CryptoJS.enc.Base64));
    return encryptByAES(message,key)
}
function decryptByECDH(message, shareKey) {
    const aesKey = CryptoJS.SHA256(shareKey);
    const key = CryptoJS.enc.Base64.parse(aesKey.toString(CryptoJS.enc.Base64));
    return decryptByAES(message,key)
}
function encryptByAES(message, key) {
    const iv = CryptoJS.enc.Utf8.parse("0102030405060708");
    const encrypted = CryptoJS.AES.encrypt(message, key, { iv: iv , mode: CryptoJS.mode.CBC, padding: CryptoJS.pad.Pkcs7 });
    return encrypted.toString();
}
function decryptByAES(message, key) {
    const iv = CryptoJS.enc.Utf8.parse("0102030405060708");
    const bytes = CryptoJS.AES.decrypt(message, key, { iv: iv, mode: CryptoJS.mode.CBC, padding: CryptoJS.pad.Pkcs7 });
    const originalText = bytes.toString(CryptoJS.enc.Utf8);
    return originalText;
}