bcpkix/src/main/java/org/bouncycastle/cert/selector/jcajce/JcaX509CertificateHolderSelector.java

package org.bouncycastle.cert.selector.jcajce;

import java.math.BigInteger;
import java.security.cert.X509Certificate;

import javax.security.auth.x500.X500Principal;

import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.x500.X500Name;
import org.bouncycastle.asn1.x509.Extension;
import org.bouncycastle.cert.selector.X509CertificateHolderSelector;

public class JcaX509CertificateHolderSelector
    extends X509CertificateHolderSelector
{
    /**
     * Construct a signer identifier based on the issuer, serial number and subject key identifier (if present) of the passed in
     * certificate.
     *
     * @param certificate certificate providing the issue and serial number and subject key identifier.
     */
    public JcaX509CertificateHolderSelector(X509Certificate certificate)
    {
        super(convertPrincipal(certificate.getIssuerX500Principal()), certificate.getSerialNumber(), getSubjectKeyId(certificate));
    }

    /**
     * Construct a signer identifier based on the provided issuer and serial number..
     *
     * @param issuer the issuer to use.
     * @param serialNumber  the serial number to use.
     */
    public JcaX509CertificateHolderSelector(X500Principal issuer, BigInteger serialNumber)
    {
        super(convertPrincipal(issuer), serialNumber);
    }

    /**
     * Construct a signer identifier based on the provided issuer, serial number, and subjectKeyId..
     *
     * @param issuer the issuer to use.
     * @param serialNumber  the serial number to use.
     * @param subjectKeyId the subject key ID to use.
     */
    public JcaX509CertificateHolderSelector(X500Principal issuer, BigInteger serialNumber, byte[] subjectKeyId)
    {
        super(convertPrincipal(issuer), serialNumber, subjectKeyId);
    }

    private static X500Name convertPrincipal(X500Principal issuer)
    {
        if (issuer == null)
        {
            return null;
        }
        return X500Name.getInstance(issuer.getEncoded());
    }

    private static byte[] getSubjectKeyId(X509Certificate cert)
    {
        byte[] ext = cert.getExtensionValue(Extension.subjectKeyIdentifier.getId());

        if (ext != null)
        {
            return ASN1OctetString.getInstance(ASN1OctetString.getInstance(ext).getOctets()).getOctets();
        }
        else
        {
            return null;
        }
    }
}