java - Web3j ECKeyPair 到 KeyPair

Question

我正在尝试使用 web3j 使用生成的 key 创建 ECC。我有 ECKeyPair对象，但 cipher.init() 要求第二个参数是 Key 对象。 ECKeyPair返回私钥和公钥的 BigInteger ，如何将它们转换为包含 PrivateKey 和 PublicKey 对象的 KeyPair ？

我已经尝试过(引用:CryptoUtil.java):

private fun decodeKeyPair(ecKeyPair: ECKeyPair): KeyPair {
        val xp = getNamedCurveByName("secp256k1")
        val p = ECNamedCurveSpec("secp256k1", xp.curve, xp.g, xp.n, xp.h, null)
        val curve = convertCurve(p.curve)
        val g = EC5Util.convertPoint(curve, p.generator, false)
        val n = p.order
        val h = BigInteger.valueOf(p.cofactor.toLong())
        val dp = ECDomainParameters(curve, g, n, h)

        val bytes = Numeric.toBytesPadded(ecKeyPair.publicKey, 64)
        val x = Numeric.toBigInt(Arrays.copyOfRange(bytes, 0, 32))
        val y = Numeric.toBigInt(Arrays.copyOfRange(bytes, 32, 64))
        val q = curve.createPoint(x, y)
        val publicKey = BCECPublicKey(
           "EC",
            ECPublicKeyParameters(q, dp),
            BouncyCastleProvider.CONFIGURATION
        )
        val privateKey = BCECPrivateKey(
            "EC",
            ECPrivateKeyParameters(ecKeyPair.privateKey, dp),
            publicKey,
            p,
            BouncyCastleProvider.CONFIGURATION
        )
        return KeyPair(publicKey, privateKey)
    }

但这会返回一个错误:引起:java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法“org.bouncycaSTLe.math.ec.ECCurve org.bouncycaSTLe.jce.spec.ECParameterSpec.getCurve()”

还有没有其他方法可以转换Web3j ECKeyPair到 key 对？

Answer 1

在探索了https://www.programcreek.com之后我终于得到了它。 。这里的主要内容是“如何使用公钥字符串生成 ECPoint”。

这是我的做法，我没有转换整个 EcKeyPair 对象，而是单独转换 key 。

公钥字符串到ECPublicKey:

private fun toEcPublicKey(publicKey: String): ECPublicKey {
        val params = ECNamedCurveTable.getParameterSpec("secp256k1")
        val curveSpec = ECNamedCurveSpec("secp256k1", params.curve, params.g, params.n)

        //This is the part how to generate ECPoint manually from public key string.
        val pubKeyX = publicKey.substring(0, publicKey.length / 2)
        val pubKeyY = publicKey.substring(publicKey.length / 2)
        val ecPoint = ECPoint(BigInteger(pubKeyX, 16), BigInteger(pubKeyY, 16))

        val params2 = EC5Util.convertSpec(curveSpec.curve, params)

        val keySpec = java.security.spec.ECPublicKeySpec(ecPoint, params2)
        val factory = KeyFactory.getInstance("ECDSA")
        return factory.generatePublic(keySpec) as ECPublicKey
}

私钥字符串到ECPrivateKey:

private fun toEcPrivateKey(privateKey: String): ECPrivateKey {
        val ecKeyPair = ECKeyPair.create(Numeric.hexStringToByteArray(privateKey))

        val params = ECNamedCurveTable.getParameterSpec("secp256k1")
        val curveSpec = ECNamedCurveSpec("secp256k1", params.curve, params.g, params.n)

        val keySpec = java.security.spec.ECPrivateKeySpec(
            ecKeyPair.privateKey,
            curveSpec)

        val factory = KeyFactory.getInstance("ECDSA")
        return factory.generatePrivate(keySpec) as ECPrivateKey
}

字符串键输入是从 Web3j 生成的图书馆。