我正在将一个方法从 nodeSJ 转换为 Java,但我无法使其正常工作。我一直在尝试计算派生共享 secret 。
希望有人能发现我在将 NodeJS 移植到 Java 时做错了什么。
NodeJS 代码:
//the public_key param here is from a different device.
sign: function(public_key)
{
//dummy values
var PRE_SALT_VALUE = 'f0f0f0f0f0';
var POST_SALT_VALUE = '0101010101';
const crypto = require('crypto');
var sha512 = crypto.createHash("sha512");
var EC = require('elliptic').ec;
var ec = new EC('p256');
// Generate keys
var key1 = ec.genKeyPair(); //key1 is gen before pub key
var key2 = ec.keyFromPublic(public_key, 'hex') //pub key gen from saved cert
var derived_secret = key1.derive(key2.getPublic());
var derived_secret = Buffer.from(derived_secret.toString(16), 'hex')
var public_key_client = key1.getPublic('hex')
var pre_salt = Buffer.from(PRE_SALT_VALUE, 'hex')
var post_salt = Buffer.from(POST_SALT_VALUE, 'hex')
derived_secret = Buffer.from(pre_salt.toString('hex')+derived_secret.toString('hex')+post_salt.toString('hex'), 'hex') // finalyze shared secret
// Hash shared secret
var sha = sha512.update(derived_secret);
derived_secret = sha.digest();
return {
public_key: public_key_client.toString('hex').slice(2), //anyone know why we drop the first byte here?
secret: derived_secret.toString('hex')
}
}
正在进行的 Java 代码:
//load cert from pem string (passed in from file), foreign cert
ByteArrayInputStream input = new ByteArrayInputStream(pem);
CertificateFactory cf = CertificateFactory.getInstance("X.509");
Certificate cert = cf.generateCertificate(input);
X509Certificate x509Cert = (X509Certificate) cert;
// get pub key from cert
PublicKey publicKeyForSignature = x509Cert.getPublicKey();
// Generate ephemeral ECDH keypair KEY1
KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC");
kpg.initialize(256);
KeyPair kp1 = kpg.generateKeyPair();
byte[] ourPk = kp1.getPublic().getEncoded(); //use this later
//load KEY2 from others public key
KeyFactory kf = KeyFactory.getInstance("EC");
X509EncodedKeySpec pkSpec = new X509EncodedKeySpec(publicKeyForSignature.getEncoded());
PublicKey otherPublicKey = kf.generatePublic(pkSpec);
// Perform key agreement
KeyAgreement ka = KeyAgreement.getInstance("ECDH");
ka.init(kp1.getPrivate());
ka.doPhase(otherPublicKey, true);
// Read shared secret
byte[] sharedSecret = ka.generateSecret();
// Derive a key from the shared secret and both salt keys
MessageDigest hash = MessageDigest.getInstance("SHA-512");
hash.update(Util.PRE_SALT_VALUE);
hash.update(sharedSecret);
hash.update(Util.POST_SALT_VALUE);
byte[] derivedKey = hash.digest();
... etc, derivedKey = secret returned in JS method, ourPk = public_key returned in JS method.
我注意到的一件事是,nodejs 与 java 生成的公钥/私钥大小不同? Node 中为 65 字节,java 中为 91 字节。不知道为什么会发生这种情况。
这里哪里出了问题?
谢谢
编辑:
所以基本上,我只需要知道如何在 Java 中做到这一点
var EC = require('elliptic').ec;
var ec = new EC('p256');
// Generate keys
var key1 = ec.genKeyPair();
var key2 = ec.keyFromPublic(public_key, 'hex') //pub key from foreign device
var derived_secret = key1.derive(key2.getPublic());
最佳答案
就像评论中已经提到的那样,为了能够使用 Java 和 Node 之间的共享 key ,您需要相应地转换 key 。
对于这两个很好的 stackoverflow 答案中的关键转换代码,可以使用:
https://stackoverflow.com/a/57209308/2331445
https://stackoverflow.com/a/36033552
测试
要获得完整的测试用例,可以编写一个 Java 程序来生成 DER 公钥,将其转换为未压缩的 EC key (65 字节)并将其输出到控制台。然后它从控制台读取另一个 PK,将其转换为公钥,并打印出共享 key 。
Node 代码使用来自 Java 程序的 PK,确定共享 secret 和公钥。然后可以通过复制/粘贴将该公钥传递给仍在等待输入的 Java 程序。
Java 程序最终确定共享 secret 并将其打印出来。
如果两个共享 key 具有相同的值,我们就知道它有效。
Java
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERBitString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.jce.ECNamedCurveTable;
import org.bouncycastle.jce.ECPointUtil;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;
import org.bouncycastle.jce.spec.ECNamedCurveSpec;
import javax.crypto.KeyAgreement;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.security.*;
import java.security.spec.ECPoint;
import java.security.spec.ECPublicKeySpec;
import java.security.spec.InvalidKeySpecException;
public class Main {
public static byte[] ecKeyBytesFromDERKey(byte[] ourPk) {
ASN1Sequence sequence = DERSequence.getInstance(ourPk);
DERBitString subjectPublicKey = (DERBitString) sequence.getObjectAt(1);
return subjectPublicKey.getBytes();
}
private static PublicKey publicKeyFromEC(byte[] ecKeyByteArray) throws NoSuchProviderException, NoSuchAlgorithmException, InvalidKeySpecException {
KeyFactory kf = KeyFactory.getInstance("EC", "BC");
ECNamedCurveParameterSpec spec = ECNamedCurveTable.getParameterSpec("secp256r1");
ECNamedCurveSpec params = new ECNamedCurveSpec("secp256r1", spec.getCurve(), spec.getG(), spec.getN());
ECPoint publicPoint = ECPointUtil.decodePoint(params.getCurve(), ecKeyByteArray);
ECPublicKeySpec pubKeySpec = new ECPublicKeySpec(publicPoint, params);
return kf.generatePublic(pubKeySpec);
}
public static void main(String[] args) throws Exception {
Security.addProvider(new BouncyCastleProvider());
KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC", "BC");
kpg.initialize(256);
KeyPair kp = kpg.generateKeyPair();
byte[] ourPk = kp.getPublic().getEncoded();
byte[] ecPublicKey = ecKeyBytesFromDERKey(ourPk);
System.out.println("our ec public key (65 bytes): " + Hex.encodeHexString(ecPublicKey));
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
System.out.println("other public key (65 bytes): ");
String input = br.readLine();
br.close();
byte[] otherPk = Hex.decodeHex(input);
PublicKey otherPublicKey = publicKeyFromEC(otherPk);
KeyAgreement ka = KeyAgreement.getInstance("ECDH");
ka.init(kp.getPrivate());
ka.doPhase(otherPublicKey, true);
byte[] sharedSecret = ka.generateSecret();
System.out.println("Shared secret: " + Hex.encodeHexString(sharedSecret));
}
}
Node
您的 Node 程序需要进行一项更改:
在行
public_key: public_key_client.toString('hex').slice(2), //anyone know why we drop the first byte here?
需要删除.slice(2)
:
public_key: public_key_client.toString('hex'),
因为它删除了表明它是未压缩 key 所需的第一个字节(十六进制 04)。
因此,只需使用 Java 程序中的公钥(每次运行都会有所不同), Node 部分可能如下所示:
var publickey = Buffer.from("<public key from java>", 'hex');
var derived = sign(publickey);
console.log(derived);
测试
在上部区域中您可以看到 Java 程序,在下部区域中可以看到 Node 程序的输出。共享的 secret 是相同的。
关于java - 使用现有的外部公钥从 ECDH 导出共享 secret ,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/57238837/