package org.bouncycastle.asn1.isismtt.ocsp;

import org.bouncycastle.asn1.ASN1Encodable;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DERObject;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;

ISIS-MTT PROFILE: The responder may include this extension in a response to
send the hash of the requested certificate to the responder. This hash is
cryptographically bound to the certificate and serves as evidence that the
certificate is known to the responder (i.e. it has been issued and is present
in the directory). Hence, this extension is a means to provide a positive
statement of availability as described in T8.[8]. As explained in T13.[1],
clients may rely on this information to be able to validate signatures after
the expiry of the corresponding certificate. Hence, clients MUST support this
extension. If a positive statement of availability is to be delivered, this
extension syntax and OID MUST be used.


    CertHash ::= SEQUENCE {
      hashAlgorithm AlgorithmIdentifier,
      certificateHash OCTET STRING
    }

/**
 * ISIS-MTT PROFILE: The responder may include this extension in a response to
 * send the hash of the requested certificate to the responder. This hash is
 * cryptographically bound to the certificate and serves as evidence that the
 * certificate is known to the responder (i.e. it has been issued and is present
 * in the directory). Hence, this extension is a means to provide a positive
 * statement of availability as described in T8.[8]. As explained in T13.[1],
 * clients may rely on this information to be able to validate signatures after
 * the expiry of the corresponding certificate. Hence, clients MUST support this
 * extension. If a positive statement of availability is to be delivered, this
 * extension syntax and OID MUST be used.
 * <p/>
 * <p/>
 * <pre>
 *     CertHash ::= SEQUENCE {
 *       hashAlgorithm AlgorithmIdentifier,
 *       certificateHash OCTET STRING
 *     }
 * </pre>
 */
public class CertHash
    extends ASN1Encodable
{

    private AlgorithmIdentifier hashAlgorithm;
    private byte[] certificateHash;

    public static CertHash getInstance(Object obj)
    {
        if (obj == null || obj instanceof CertHash)
        {
            return (CertHash)obj;
        }

        if (obj instanceof ASN1Sequence)
        {
            return new CertHash((ASN1Sequence)obj);
        }

        throw new IllegalArgumentException("illegal object in getInstance: "
            + obj.getClass().getName());
    }

    
Constructor from ASN1Sequence.

The sequence is of type CertHash:

    CertHash ::= SEQUENCE {
      hashAlgorithm AlgorithmIdentifier,
      certificateHash OCTET STRING
    }

Params:
seq – The ASN.1 sequence./**
     * Constructor from ASN1Sequence.
     * <p/>
     * The sequence is of type CertHash:
     * <p/>
     * <pre>
     *     CertHash ::= SEQUENCE {
     *       hashAlgorithm AlgorithmIdentifier,
     *       certificateHash OCTET STRING
     *     }
     * </pre>
     *
     * @param seq The ASN.1 sequence.
     */
    private CertHash(ASN1Sequence seq)
    {
        if (seq.size() != 2)
        {
            throw new IllegalArgumentException("Bad sequence size: "
                + seq.size());
        }
        hashAlgorithm = AlgorithmIdentifier.getInstance(seq.getObjectAt(0));
        certificateHash = DEROctetString.getInstance(seq.getObjectAt(1)).getOctets();
    }

    
Constructor from a given details.
Params:
hashAlgorithm –   The hash algorithm identifier.
certificateHash – The hash of the whole DER encoding of the certificate./**
     * Constructor from a given details.
     *
     * @param hashAlgorithm   The hash algorithm identifier.
     * @param certificateHash The hash of the whole DER encoding of the certificate.
     */
    public CertHash(AlgorithmIdentifier hashAlgorithm, byte[] certificateHash)
    {
        this.hashAlgorithm = hashAlgorithm;
        this.certificateHash = new byte[certificateHash.length];
        System.arraycopy(certificateHash, 0, this.certificateHash, 0,
            certificateHash.length);
    }

    public AlgorithmIdentifier getHashAlgorithm()
    {
        return hashAlgorithm;
    }

    public byte[] getCertificateHash()
    {
        return certificateHash;
    }

    
Produce an object suitable for an ASN1OutputStream.

Returns:

    CertHash ::= SEQUENCE {
      hashAlgorithm AlgorithmIdentifier,
      certificateHash OCTET STRING
    }

Returns:
a DERObject/**
     * Produce an object suitable for an ASN1OutputStream.
     * <p/>
     * Returns:
     * <p/>
     * <pre>
     *     CertHash ::= SEQUENCE {
     *       hashAlgorithm AlgorithmIdentifier,
     *       certificateHash OCTET STRING
     *     }
     * </pre>
     *
     * @return a DERObject
     */
    public DERObject toASN1Object()
    {
        ASN1EncodableVector vec = new ASN1EncodableVector();
        vec.add(hashAlgorithm);
        vec.add(new DEROctetString(certificateHash));
        return new DERSequence(vec);
    }
}