Java-使用ECDSA创建XML数字签名(椭圆曲线)

我们可以使用RSA密钥创建XML数字签名.但是如何使用椭圆曲线键来签署xml文件？我收到错误消息,如 -

Exception in thread "main" java.security.KeyException: ECKeyValue not supported
    at org.jcp.xml.dsig.internal.dom.DOMKeyValue$EC.(DOMKeyValue.java:350)
    at org.jcp.xml.dsig.internal.dom.DOMKeyInfoFactory.newKeyValue(DOMKeyInfoFactory.java:71)
    at csr.ExtractEC.main(XMLSignatureECTest.java:57)
Caused by: java.lang.ClassNotFoundException: sun/security/ec/ECParameters
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    at org.jcp.xml.dsig.internal.dom.DOMKeyValue$EC.getMethods(DOMKeyValue.java:367)
    at org.jcp.xml.dsig.internal.dom.DOMKeyValue$EC$1.run(DOMKeyValue.java:343)
    at org.jcp.xml.dsig.internal.dom.DOMKeyValue$EC$1.run(DOMKeyValue.java:339)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.jcp.xml.dsig.internal.dom.DOMKeyValue$EC.(DOMKeyValue.java:338)
    ... 2 more

我用下面的代码创建了SignatureMethod和KeyInfo -

String url = "http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha256";
        SignatureMethod signatureMethod = factory.newSignatureMethod(url, null);
        SignedInfo signedInfo = factory.newSignedInfo(c14n, signatureMethod, Collections.singletonList(reference));

        PrivateKey privateKey = Utils.generatePrivateEC("e:\\certs\\ec\\ec.key.p8");
        Certificate certificate = Utils.generatePublic("e:\\certs\\ec\\ec.cer");
        KeyInfoFactory keyInfoFactory = factory.getKeyInfoFactory();
        KeyValue keyValue = keyInfoFactory.newKeyValue(certificate.getPublicKey());
        KeyInfo keyInfo = keyInfoFactory.newKeyInfo(Collections.singletonList(keyValue));

JDK - Oracle JDK 8安全提供商 - BouncyCastle和Sun.