package org.bouncycastle.asn1.cms;
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.DEROctetString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.util.Arrays;
/**
* <a href="http://tools.ietf.org/html/rfc5084">RFC 5084</a>: GCMParameters object.
* <p>
* <pre>
GCMParameters ::= SEQUENCE {
aes-nonce OCTET STRING, -- recommended size is 12 octets
aes-ICVlen AES-GCM-ICVlen DEFAULT 12 }
* </pre>
*/
public class GCMParameters
extends ASN1Object
{
private byte[] nonce;
private int icvLen;
/**
* Return an GCMParameters object from the given object.
* <p>
* Accepted inputs:
* <ul>
* <li> null → null
* <li> {@link org.bouncycastle.asn1.cms.GCMParameters} object
* <li> {@link org.bouncycastle.asn1.ASN1Sequence#getInstance(Object) ASN1Sequence} input formats with GCMParameters structure inside
* </ul>
*
* @param obj the object we want converted.
* @exception IllegalArgumentException if the object cannot be converted.
*/
public static GCMParameters getInstance(
Object obj)
{
if (obj instanceof GCMParameters)
{
return (GCMParameters)obj;
}
else if (obj != null)
{
return new GCMParameters(ASN1Sequence.getInstance(obj));
}
return null;
}
private GCMParameters(
ASN1Sequence seq)
{
this.nonce = ASN1OctetString.getInstance(seq.getObjectAt(0)).getOctets();
if (seq.size() == 2)
{
this.icvLen = ASN1Integer.getInstance(seq.getObjectAt(1)).getValue().intValue();
}
else
{
this.icvLen = 12;
}
}
public GCMParameters(
byte[] nonce,
int icvLen)
{
this.nonce = Arrays.clone(nonce);
this.icvLen = icvLen;
}
public byte[] getNonce()
{
return Arrays.clone(nonce);
}
public int getIcvLen()
{
return icvLen;
}
public ASN1Primitive toASN1Primitive()
{
ASN1EncodableVector v = new ASN1EncodableVector();
v.add(new DEROctetString(nonce));
if (icvLen != 12)
{
v.add(new ASN1Integer(icvLen));
}
return new DERSequence(v);
}
}