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 * reserved comment block

 * DO NOT REMOVE OR ALTER!

 */

/**

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements. See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership. The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License. You may obtain a copy of the License at

 *

 * http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing,

 * software distributed under the License is distributed on an

 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

 * KIND, either express or implied. See the License for the

 * specific language governing permissions and limitations

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package com.sun.org.apache.xml.internal.security.keys.content.keyvalues;

import java.io.IOException;

import java.math.BigInteger;

import java.security.Key;

import java.security.KeyFactory;

import java.security.NoSuchAlgorithmException;

import java.security.PublicKey;

import java.security.interfaces.ECPublicKey;

import java.security.spec.ECField;

import java.security.spec.ECFieldFp;

import java.security.spec.ECParameterSpec;

import java.security.spec.ECPoint;

import java.security.spec.ECPublicKeySpec;

import java.security.spec.EllipticCurve;

import java.security.spec.InvalidKeySpecException;

import java.util.Arrays;

import javax.xml.crypto.MarshalException;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.Node;

import org.w3c.dom.Text;

import com.sun.org.apache.xml.internal.security.exceptions.XMLSecurityException;

import com.sun.org.apache.xml.internal.security.utils.Constants;

import com.sun.org.apache.xml.internal.security.utils.I18n;

import com.sun.org.apache.xml.internal.security.utils.Signature11ElementProxy;

import com.sun.org.apache.xml.internal.security.utils.XMLUtils;

public class ECKeyValue extends Signature11ElementProxy implements KeyValueContent {

    /* Supported curve, secp256r1 */

    private static final Curve SECP256R1 = initializeCurve(

        "secp256r1 [NIST P-256, X9.62 prime256v1]",

        "1.2.840.10045.3.1.7",

        "FFFFFFFF00000001000000000000000000000000FFFFFFFFFFFFFFFFFFFFFFFF",

        "FFFFFFFF00000001000000000000000000000000FFFFFFFFFFFFFFFFFFFFFFFC",

        "5AC635D8AA3A93E7B3EBBD55769886BC651D06B0CC53B0F63BCE3C3E27D2604B",

        "6B17D1F2E12C4247F8BCE6E563A440F277037D812DEB33A0F4A13945D898C296",

        "4FE342E2FE1A7F9B8EE7EB4A7C0F9E162BCE33576B315ECECBB6406837BF51F5",

        "FFFFFFFF00000000FFFFFFFFFFFFFFFFBCE6FAADA7179E84F3B9CAC2FC632551",

        1

    );

    /* Supported curve secp384r1 */

    private static final Curve SECP384R1 = initializeCurve(

        "secp384r1 [NIST P-384]",

        "1.3.132.0.34",

        "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF0000000000000000FFFFFFFF",

        "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF0000000000000000FFFFFFFC",

        "B3312FA7E23EE7E4988E056BE3F82D19181D9C6EFE8141120314088F5013875AC656398D8A2ED19D2A85C8EDD3EC2AEF",

        "AA87CA22BE8B05378EB1C71EF320AD746E1D3B628BA79B9859F741E082542A385502F25DBF55296C3A545E3872760AB7",

        "3617DE4A96262C6F5D9E98BF9292DC29F8F41DBD289A147CE9DA3113B5F0B8C00A60B1CE1D7E819D7A431D7C90EA0E5F",

        "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC7634D81F4372DDF581A0DB248B0A77AECEC196ACCC52973",

        1

    );

    /* Supported curve secp521r1 */

    private static final Curve SECP521R1 = initializeCurve(

        "secp521r1 [NIST P-521]",

        "1.3.132.0.35",

        "01FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",

        "01FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC",

        "0051953EB9618E1C9A1F929A21A0B68540EEA2DA725B99B315F3B8B489918EF109E156193951EC7E937B1652C0BD3BB1BF073573DF883D2C34F1EF451FD46B503F00",

        "00C6858E06B70404E9CD9E3ECB662395B4429C648139053FB521F828AF606B4D3DBAA14B5E77EFE75928FE1DC127A2FFA8DE3348B3C1856A429BF97E7E31C2E5BD66",

        "011839296A789A3BC0045C8A5FB42C7D1BD998F54449579B446817AFBD17273E662C97EE72995EF42640C550B9013FAD0761353C7086A272C24088BE94769FD16650",

        "01FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFA51868783BF2F966B7FCC0148F709A5D03BB5C9B8899C47AEBB6FB71E91386409",

        1

    );

    private static Curve initializeCurve(String name, String oid,

            String sfield, String a, String b,

            String x, String y, String n, int h) {

        BigInteger p = bigInt(sfield);

        ECField field = new ECFieldFp(p);

        EllipticCurve curve = new EllipticCurve(field, bigInt(a),

                                                bigInt(b));

        ECPoint g = new ECPoint(bigInt(x), bigInt(y));

        return new Curve(name, oid, curve, g, bigInt(n), h);

    }

    /**

     * Constructor DSAKeyValue

     *

     * @param element

     * @param baseURI

     * @throws XMLSecurityException

     */

    public ECKeyValue(Element element, String baseURI) throws XMLSecurityException {

        super(element, baseURI);

    }

    /**

     * Constructor DSAKeyValue

     *

     * @param doc

     * @param key

     * @throws IllegalArgumentException

     */

    public ECKeyValue(Document doc, Key key) throws IllegalArgumentException {

        super(doc);

        addReturnToSelf();

        if (key instanceof ECPublicKey) {

            ECParameterSpec ecParams = ((ECPublicKey)key).getParams();

            // NamedCurve

            String oid = getCurveOid(ecParams);

            if (oid == null) {

                throw new IllegalArgumentException("Invalid ECParameterSpec");

            }

            Element namedCurveElement = XMLUtils.createElementInSignature11Space(getDocument(), "NamedCurve");

            namedCurveElement.setAttributeNS(null, "URI", "urn:oid:" + oid);

            appendSelf(namedCurveElement);

            addReturnToSelf();

            // PublicKey

            ECPoint ecPoint = ((ECPublicKey)key).getW();

            byte[] secPublicKey = encodePoint(ecPoint, ecParams.getCurve());

            String encoded = XMLUtils.encodeToString(secPublicKey);

            Element publicKeyElement = XMLUtils.createElementInSignature11Space(getDocument(), "PublicKey");

            Text text = getDocument().createTextNode(encoded);

            publicKeyElement.appendChild(text);

            appendSelf(publicKeyElement);

            addReturnToSelf();

        } else {

            Object[] exArgs = { Constants._TAG_ECKEYVALUE, key.getClass().getName() };

            throw new IllegalArgumentException(I18n.translate("KeyValue.IllegalArgument", exArgs));

        }

    }

    /** {@inheritDoc} */

    public PublicKey getPublicKey() throws XMLSecurityException {

        try {

            ECParameterSpec ecParams = null;

            Element curElem = getFirstChildElement(getElement());

            if (curElem == null) {

                throw new MarshalException("KeyValue must contain at least one type");

            }

            if ("ECParameters".equals(curElem.getLocalName())

                && Constants.SignatureSpec11NS.equals(curElem.getNamespaceURI())) {

                throw new UnsupportedOperationException

                    ("ECParameters not supported");

            } else if ("NamedCurve".equals(curElem.getLocalName())

                && Constants.SignatureSpec11NS.equals(curElem.getNamespaceURI())) {

                String uri = null;

                if (curElem.hasAttributeNS(null, "URI")) {

                    uri = curElem.getAttributeNS(null, "URI");

                }

                // strip off "urn:oid"

                if (uri != null && uri.startsWith("urn:oid:")) {

                    String oid = uri.substring("urn:oid:".length());

                    ecParams = getECParameterSpec(oid);

                    if (ecParams == null) {

                        throw new MarshalException("Invalid curve OID");

                    }

                } else {

                    throw new MarshalException("Invalid NamedCurve URI");

                }

            } else {

                throw new MarshalException("Invalid ECKeyValue");

            }

            curElem = getNextSiblingElement(curElem, "PublicKey", Constants.SignatureSpec11NS);

            ECPoint ecPoint = null;

            try {

                String content = XMLUtils.getFullTextChildrenFromNode(curElem);

                ecPoint = decodePoint(XMLUtils.decode(content), ecParams.getCurve());

            } catch (IOException ioe) {

                throw new MarshalException("Invalid EC Point", ioe);

            }

            ECPublicKeySpec spec = new ECPublicKeySpec(ecPoint, ecParams);

            return KeyFactory.getInstance("EC").generatePublic(spec);

        } catch (NoSuchAlgorithmException | InvalidKeySpecException | MarshalException ex) {

            throw new XMLSecurityException(ex);

        }

    }

    /** {@inheritDoc} */

    public String getBaseLocalName() {

        return Constants._TAG_ECKEYVALUE;

    }

    private static Element getFirstChildElement(Node node) {

        Node child = node.getFirstChild();

        while (child != null && child.getNodeType() != Node.ELEMENT_NODE) {

            child = child.getNextSibling();

        }

        return (Element)child;

    }

    private static Element getNextSiblingElement(Node node, String localName, String namespaceURI)

        throws MarshalException

    {

        return verifyElement(getNextSiblingElement(node), localName, namespaceURI);

    }

    private static Element getNextSiblingElement(Node node) {

        Node sibling = node.getNextSibling();

        while (sibling != null && sibling.getNodeType() != Node.ELEMENT_NODE) {

            sibling = sibling.getNextSibling();

        }

        return (Element)sibling;

    }

    private static Element verifyElement(Element elem, String localName, String namespaceURI)

        throws MarshalException

    {

        if (elem == null) {

            throw new MarshalException("Missing " + localName + " element");

        }

        String name = elem.getLocalName();

        String namespace = elem.getNamespaceURI();

        if (!name.equals(localName) || namespace == null && namespaceURI != null

            || namespace != null && !namespace.equals(namespaceURI)) {

            throw new MarshalException("Invalid element name: " +

                namespace + ":" + name + ", expected " + namespaceURI + ":" + localName);

        }

        return elem;

    }

    private static String getCurveOid(ECParameterSpec params) {

        // Check that the params represent one of the supported

        // curves. If there is a match, return the object identifier

        // of the curve.

        Curve match;

        if (matchCurve(params, SECP256R1)) {

            match = SECP256R1;

        } else if (matchCurve(params, SECP384R1)) {

            match = SECP384R1;

        } else if (matchCurve(params, SECP521R1)) {

            match = SECP521R1;

        } else {

            return null;

        }

        return match.getObjectId();

    }

    private static boolean matchCurve(ECParameterSpec params, Curve curve) {

        int fieldSize = params.getCurve().getField().getFieldSize();

        return curve.getCurve().getField().getFieldSize() == fieldSize

            && curve.getCurve().equals(params.getCurve())

            && curve.getGenerator().equals(params.getGenerator())

            && curve.getOrder().equals(params.getOrder())

            && curve.getCofactor() == params.getCofactor();

    }

    private static ECPoint decodePoint(byte[] data, EllipticCurve curve)

        throws IOException {

        if (data.length == 0 || data[0] != 4) {

            throw new IOException("Only uncompressed point format " +

                "supported");

        }

        // Per ANSI X9.62, an encoded point is a 1 byte type followed by

        // ceiling(LOG base 2 field-size / 8) bytes of x and the same of y.

        int n = (data.length - 1) / 2;

        if (n != (curve.getField().getFieldSize() + 7) >> 3) {

            throw new IOException("Point does not match field size");

        }

        byte[] xb = Arrays.copyOfRange(data, 1, 1 + n);

        byte[] yb = Arrays.copyOfRange(data, n + 1, n + 1 + n);

        return new ECPoint(new BigInteger(1, xb), new BigInteger(1, yb));

    }

    private static byte[] encodePoint(ECPoint point, EllipticCurve curve) {

        // get field size in bytes (rounding up)

        int n = (curve.getField().getFieldSize() + 7) >> 3;

        byte[] xb = trimZeroes(point.getAffineX().toByteArray());

        byte[] yb = trimZeroes(point.getAffineY().toByteArray());

        if (xb.length > n || yb.length > n) {

            throw new RuntimeException("Point coordinates do not " +

                                       "match field size");

        }

        byte[] b = new byte[1 + (n << 1)];

        b[0] = 4; // uncompressed

        System.arraycopy(xb, 0, b, n - xb.length + 1, xb.length);

        System.arraycopy(yb, 0, b, b.length - yb.length, yb.length);

        return b;

    }

    private static byte[] trimZeroes(byte[] b) {

        int i = 0;

        while (i < b.length - 1 && b[i] == 0) {

            i++;

        }

        if (i == 0) {

            return b;

        }

        return Arrays.copyOfRange(b, i, b.length);

    }

    private static ECParameterSpec getECParameterSpec(String oid) {

        if (oid.equals(SECP256R1.getObjectId())) {

            return SECP256R1;

        } else if (oid.equals(SECP384R1.getObjectId())) {

            return SECP384R1;

        } else if (oid.equals(SECP521R1.getObjectId())) {

            return SECP521R1;

        } else {

            return null;

        }

    }

    static final class Curve extends ECParameterSpec {

        private final String name;

        private final String oid;

        Curve(String name, String oid, EllipticCurve curve,

              ECPoint g, BigInteger n, int h) {

            super(curve, g, n, h);

            this.name = name;

            this.oid = oid;

        }

        private String getName() {

            return name;

        }

        private String getObjectId() {

            return oid;

        }

    }

    private static BigInteger bigInt(String s) {

        return new BigInteger(s, 16);

    }

}