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); } }