org.bouncycastle.asn1.sec.ECPrivateKey.java Source code

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Here is the source code for org.bouncycastle.asn1.sec.ECPrivateKey.java

Source

package org.bouncycastle.asn1.sec;

import java.math.BigInteger;
import java.util.Enumeration;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Integer;
import org.bouncycastle.asn1.ASN1Object;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.ASN1TaggedObject;
import org.bouncycastle.asn1.DERBitString;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.DERTaggedObject;
import org.bouncycastle.util.BigIntegers;

/**
 * the elliptic curve private key object from SEC 1
 */
public class ECPrivateKey extends ASN1Object {
    private ASN1Sequence seq;

    private ECPrivateKey(ASN1Sequence seq) {
        this.seq = seq;
    }

    public static ECPrivateKey getInstance(Object obj) {
        if (obj instanceof ECPrivateKey) {
            return (ECPrivateKey) obj;
        }

        if (obj != null) {
            return new ECPrivateKey(ASN1Sequence.getInstance(obj));
        }

        return null;
    }

    /**
     * @deprecated use constructor which takes orderBitLength to guarantee correct encoding.
     */
    public ECPrivateKey(BigInteger key) {
        this(key.bitLength(), key);
    }

    /**
     * Base constructor.
     *
     * @param orderBitLength the bitLength of the order of the curve.
     * @param key the private key value.
     */
    public ECPrivateKey(int orderBitLength, BigInteger key) {
        byte[] bytes = BigIntegers.asUnsignedByteArray((orderBitLength + 7) / 8, key);

        ASN1EncodableVector v = new ASN1EncodableVector(2);

        v.add(new ASN1Integer(1));
        v.add(new DEROctetString(bytes));

        seq = new DERSequence(v);
    }

    /**
     * @deprecated use constructor which takes orderBitLength to guarantee correct encoding.
     */
    public ECPrivateKey(BigInteger key, ASN1Encodable parameters) {
        this(key, null, parameters);
    }

    /**
     * @deprecated use constructor which takes orderBitLength to guarantee correct encoding.
     */
    public ECPrivateKey(BigInteger key, DERBitString publicKey, ASN1Encodable parameters) {
        this(key.bitLength(), key, publicKey, parameters);
    }

    public ECPrivateKey(int orderBitLength, BigInteger key, ASN1Encodable parameters) {
        this(orderBitLength, key, null, parameters);
    }

    public ECPrivateKey(int orderBitLength, BigInteger key, DERBitString publicKey, ASN1Encodable parameters) {
        byte[] bytes = BigIntegers.asUnsignedByteArray((orderBitLength + 7) / 8, key);

        ASN1EncodableVector v = new ASN1EncodableVector(4);

        v.add(new ASN1Integer(1));
        v.add(new DEROctetString(bytes));

        if (parameters != null) {
            v.add(new DERTaggedObject(true, 0, parameters));
        }

        if (publicKey != null) {
            v.add(new DERTaggedObject(true, 1, publicKey));
        }

        seq = new DERSequence(v);
    }

    public BigInteger getKey() {
        ASN1OctetString octs = (ASN1OctetString) seq.getObjectAt(1);

        return new BigInteger(1, octs.getOctets());
    }

    public DERBitString getPublicKey() {
        return (DERBitString) getObjectInTag(1);
    }

    public ASN1Primitive getParameters() {
        return getObjectInTag(0);
    }

    private ASN1Primitive getObjectInTag(int tagNo) {
        Enumeration e = seq.getObjects();

        while (e.hasMoreElements()) {
            ASN1Encodable obj = (ASN1Encodable) e.nextElement();

            if (obj instanceof ASN1TaggedObject) {
                ASN1TaggedObject tag = (ASN1TaggedObject) obj;
                if (tag.getTagNo() == tagNo) {
                    return tag.getObject().toASN1Primitive();
                }
            }
        }
        return null;
    }

    /**
     * ECPrivateKey ::= SEQUENCE {
     *     version INTEGER { ecPrivkeyVer1(1) } (ecPrivkeyVer1),
     *     privateKey OCTET STRING,
     *     parameters [0] Parameters OPTIONAL,
     *     publicKey [1] BIT STRING OPTIONAL }
     */
    public ASN1Primitive toASN1Primitive() {
        return seq;
    }
}