001package org.apache.commons.ssl.org.bouncycastle.asn1.cms;
002
003import org.apache.commons.ssl.org.bouncycastle.asn1.ASN1EncodableVector;
004import org.apache.commons.ssl.org.bouncycastle.asn1.ASN1Integer;
005import org.apache.commons.ssl.org.bouncycastle.asn1.ASN1Object;
006import org.apache.commons.ssl.org.bouncycastle.asn1.ASN1OctetString;
007import org.apache.commons.ssl.org.bouncycastle.asn1.ASN1Primitive;
008import org.apache.commons.ssl.org.bouncycastle.asn1.ASN1Sequence;
009import org.apache.commons.ssl.org.bouncycastle.asn1.DEROctetString;
010import org.apache.commons.ssl.org.bouncycastle.asn1.DERSequence;
011import org.bouncycastle.util.Arrays;
012
013/**
014 * <a href="http://tools.ietf.org/html/rfc5084">RFC 5084</a>: GCMParameters object.
015 * <p>
016 * <pre>
017 GCMParameters ::= SEQUENCE {
018   aes-nonce        OCTET STRING, -- recommended size is 12 octets
019   aes-ICVlen       AES-GCM-ICVlen DEFAULT 12 }
020 * </pre>
021 */
022public class GCMParameters
023    extends ASN1Object
024{
025    private byte[] nonce;
026    private int icvLen;
027
028    /**
029     * Return an GCMParameters object from the given object.
030     * <p>
031     * Accepted inputs:
032     * <ul>
033     * <li> null &rarr; null
034     * <li> {@link org.bouncycastle.asn1.cms.GCMParameters} object
035     * <li> {@link org.bouncycastle.asn1.ASN1Sequence#getInstance(Object) ASN1Sequence} input formats with GCMParameters structure inside
036     * </ul>
037     *
038     * @param obj the object we want converted.
039     * @exception IllegalArgumentException if the object cannot be converted.
040     */
041    public static GCMParameters getInstance(
042        Object  obj)
043    {
044        if (obj instanceof GCMParameters)
045        {
046            return (GCMParameters)obj;
047        }
048        else if (obj != null)
049        {
050            return new GCMParameters(ASN1Sequence.getInstance(obj));
051        }
052
053        return null;
054    }
055
056    private GCMParameters(
057        ASN1Sequence seq)
058    {
059        this.nonce = ASN1OctetString.getInstance(seq.getObjectAt(0)).getOctets();
060
061        if (seq.size() == 2)
062        {
063            this.icvLen = ASN1Integer.getInstance(seq.getObjectAt(1)).getValue().intValue();
064        }
065        else
066        {
067            this.icvLen = 12;
068        }
069    }
070
071    public GCMParameters(
072        byte[] nonce,
073        int    icvLen)
074    {
075        this.nonce = Arrays.clone(nonce);
076        this.icvLen = icvLen;
077    }
078
079    public byte[] getNonce()
080    {
081        return Arrays.clone(nonce);
082    }
083
084    public int getIcvLen()
085    {
086        return icvLen;
087    }
088
089    public ASN1Primitive toASN1Primitive()
090    {
091        ASN1EncodableVector    v = new ASN1EncodableVector();
092
093        v.add(new DEROctetString(nonce));
094
095        if (icvLen != 12)
096        {
097            v.add(new ASN1Integer(icvLen));
098        }
099
100        return new DERSequence(v);
101    }
102}