从ECPrivateKey生成ECPublicKey

从ECPrivateKey生成ECPublicKey

本文介绍了从ECPrivateKey生成ECPublicKey的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我正在尝试根据给定的私钥和已知曲线生成一个公钥。下面是我的代码:

I'm trying to generate a public key given a private key and known curve. Below is my code:

// Generate Keys
ECGenParameterSpec ecGenSpec = new ECGenParameterSpec("secp256r1");
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("ECDSA", "BC");
keyPairGenerator.initialize(ecGenSpec, new SecureRandom());
java.security.KeyPair pair = keyPairGenerator.generateKeyPair();
ECPrivateKey privateKey = (ECPrivateKey) pair.getPrivate();
ECPublicKey publicKeyExpected = (ECPublicKey) pair.getPublic();

// Expected public key
System.out.print("Expected Public Key: " +
        BaseEncoding.base64Url().encode(publicKeyExpected.getEncoded()));

// Generate public key from private key
X9ECParameters ecp = SECNamedCurves.getByName("secp256r1");
ECDomainParameters domainParams = new ECDomainParameters(ecp.getCurve(),
        ecp.getG(), ecp.getN(), ecp.getH(),
        ecp.getSeed());
ECPoint Q = domainParams.getG().multiply(privateKey.getS()); // is this correct?
KeyFactory kf = KeyFactory.getInstance("ECDSA", "BC");
ECPublicKey publicKeyGenerated =
        (ECPublicKey) kf.generatePublic(new X509EncodedKeySpec(Q.getEncoded(false)));  // exception here

// Generated public key from private key
System.out.print("Generated Public Key: " +
        BaseEncoding.base64Url().encode(publicKeyGenerated.getEncoded()));

但是,当我打电话时: kf.generatePublic(new X509EncodedKeySpec(Q。 getEncoded(false)))
我得到一个例外: java.security.spec.InvalidKeySpecException:编码密钥规范无法识别(不是我的拼写错误)

However, when I call: kf.generatePublic(new X509EncodedKeySpec(Q.getEncoded(false)))I get the exception: java.security.spec.InvalidKeySpecException: encoded key spec not recognised (not my misspelling)

我似乎在错误地计算 Q ,但是我不确定我的错误在哪里。

I appears I'm incorrectly calculating Q, but I'm not sure where my error is.

感谢您的帮助!

推荐答案

以防我的未来自我需要解决方案:

In case my future self needs the solution:

// Generate Keys
ECGenParameterSpec ecGenSpec = new ECGenParameterSpec("secp256r1");
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("ECDSA", "BC");
keyPairGenerator.initialize(ecGenSpec, new SecureRandom());
java.security.KeyPair pair = keyPairGenerator.generateKeyPair();
ECPrivateKey privateKey = (ECPrivateKey) pair.getPrivate();
ECPublicKey publicKeyExpected = (ECPublicKey) pair.getPublic();

// Expected public key
System.out.print("Expected Public Key: " +
        BaseEncoding.base64Url().encode(publicKeyExpected.getEncoded()));

// Generate public key from private key
KeyFactory keyFactory = KeyFactory.getInstance("ECDSA", "BC");
ECParameterSpec ecSpec = ECNamedCurveTable.getParameterSpec("secp256r1");

ECPoint Q = ecSpec.getG().multiply(privateKey.getD());
byte[] publicDerBytes = Q.getEncoded(false);

ECPoint point = ecSpec.getCurve().decodePoint(publicDerBytes);
ECPublicKeySpec pubSpec = new ECPublicKeySpec(point, ecSpec);
ECPublicKey publicKeyGenerated = (ECPublicKey) keyFactory.generatePublic(pubSpec);

// Generated public key from private key
System.out.print("Generated Public Key: " +
        BaseEncoding.base64Url().encode(publicKeyGenerated.getEncoded()));

这篇关于从ECPrivateKey生成ECPublicKey的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!

08-14 23:55