ECDSA私钥和公钥-如何获得SecretKey

Question

我使用generateKeyPair()方法使用ECDSA算法生成了2个不同的KeyPair。

public KeyPair generateKeyPair(){           
    ECNamedCurveParameterSpec spec = ECNamedCurveTable.getParameterSpec("secp192r1");
    KeyPairGenerator g = KeyPairGenerator.getInstance("ECDSA", "BC");
    g.initialize(spec, new SecureRandom());
    return g.generateKeyPair(); 
}

然后我用PrivateKey和PublicKey从单独的KeyPair得到合并的SecretKey:

private SecretKey generateSecretKey(PrivateKey privateKey, PublicKey publicKey) {
    KeyAgreement ka = KeyAgreement.getInstance("ECDH");
    ka.init(privateKey);
    ka.doPhase(publicKey),
            true);
    return ka.generateSecret("AES");
}

但是我得到了ka.generateSecret("AES"):

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException
    at java.lang.System.arraycopy(Native Method)
    at org.bouncycastle.jcajce.provider.asymmetric.util.BaseAgreementSpi.engineGenerateSecret(Unknown Source)
    at javax.crypto.KeyAgreement.generateSecret(KeyAgreement.java:648)

如果我使用ECDSA，我得到:

Exception in thread "main" java.security.NoSuchAlgorithmException: Algorithm ECDSA not available
   at javax.crypto.KeyAgreement.getInstance(KeyAgreement.java:184)

使用DH抛出:

Exception in thread "main" java.security.InvalidKeyException: DHKeyAgreement requires DHPrivateKey
    at org.bouncycastle.jcajce.provider.asymmetric.dh.KeyAgreementSpi.engineInit(Unknown Source)
    at javax.crypto.KeyAgreement.implInit(KeyAgreement.java:346)
    at javax.crypto.KeyAgreement.chooseProvider(KeyAgreement.java:378)
    at javax.crypto.KeyAgreement.init(KeyAgreement.java:470)

如何从ECDSA算法生成的PrivateKey和PublicKey中得到组合SecretKey ?

Answer 1

从return ka.generateSecret();中删除"AES"参数后，它正常工作并返回曲线大小共享密钥:

private SecretKey generateSecretKey(PrivateKey privateKey, PublicKey publicKey) {
    KeyAgreement ka = KeyAgreement.getInstance("ECDH");
    ka.init(privateKey);
    ka.doPhase(publicKey, true);
    return ka.generateSecret();
}

Answer 2

密钥协议通常在双方之间工作，他们每一方都有自己的ECDS公钥和私钥(因此我们有四个不同的密钥)。你确定这是你想要的吗?

因此，当你同意一个密钥时，你需要a方的私钥和B方的公钥。在连接的另一端，您使用乙方的私钥和甲方的公钥

您选择的ECDH密钥协议算法在RFC3278中有描述，详细信息请阅读。