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package org.spongycastle.cms;
import java.io.IOException;
import org.spongycastle.asn1.ASN1Encodable;
import org.spongycastle.asn1.ASN1EncodableVector;
import org.spongycastle.asn1.ASN1ObjectIdentifier;
import org.spongycastle.asn1.ASN1Sequence;
import org.spongycastle.asn1.DERNull;
import org.spongycastle.asn1.DEROctetString;
import org.spongycastle.asn1.cms.KeyAgreeRecipientInfo;
import org.spongycastle.asn1.cms.OriginatorIdentifierOrKey;
import org.spongycastle.asn1.cms.OriginatorPublicKey;
import org.spongycastle.asn1.cms.RecipientInfo;
import org.spongycastle.asn1.x509.AlgorithmIdentifier;
import org.spongycastle.asn1.x509.SubjectPublicKeyInfo;
import org.spongycastle.operator.GenericKey;
public abstract class KeyAgreeRecipientInfoGenerator
implements RecipientInfoGenerator
{
private ASN1ObjectIdentifier keyAgreementOID;
private ASN1ObjectIdentifier keyEncryptionOID;
private SubjectPublicKeyInfo originatorKeyInfo;
protected KeyAgreeRecipientInfoGenerator(ASN1ObjectIdentifier keyAgreementOID, SubjectPublicKeyInfo originatorKeyInfo, ASN1ObjectIdentifier keyEncryptionOID)
{
this.originatorKeyInfo = originatorKeyInfo;
this.keyAgreementOID = keyAgreementOID;
this.keyEncryptionOID = keyEncryptionOID;
}
public RecipientInfo generate(GenericKey contentEncryptionKey)
throws CMSException
{
OriginatorIdentifierOrKey originator = new OriginatorIdentifierOrKey(
createOriginatorPublicKey(originatorKeyInfo));
ASN1EncodableVector params = new ASN1EncodableVector();
params.add(keyEncryptionOID);
params.add(DERNull.INSTANCE);
AlgorithmIdentifier keyEncAlg = new AlgorithmIdentifier(keyEncryptionOID, DERNull.INSTANCE);
AlgorithmIdentifier keyAgreeAlg = new AlgorithmIdentifier(keyAgreementOID, keyEncAlg);
ASN1Sequence recipients = generateRecipientEncryptedKeys(keyAgreeAlg, keyEncAlg, contentEncryptionKey);
ASN1Encodable userKeyingMaterial = getUserKeyingMaterial(keyAgreeAlg);
if (userKeyingMaterial != null)
{
try
{
return new RecipientInfo(new KeyAgreeRecipientInfo(originator, new DEROctetString(userKeyingMaterial),
keyAgreeAlg, recipients));
}
catch (IOException e)
{
throw new CMSException("unable to encode userKeyingMaterial: " + e.getMessage(), e);
}
}
else
{
return new RecipientInfo(new KeyAgreeRecipientInfo(originator, null,
keyAgreeAlg, recipients));
}
}
protected OriginatorPublicKey createOriginatorPublicKey(SubjectPublicKeyInfo originatorKeyInfo)
{
return new OriginatorPublicKey(
new AlgorithmIdentifier(originatorKeyInfo.getAlgorithm().getAlgorithm(), DERNull.INSTANCE),
originatorKeyInfo.getPublicKeyData().getBytes());
}
protected abstract ASN1Sequence generateRecipientEncryptedKeys(AlgorithmIdentifier keyAgreeAlgorithm, AlgorithmIdentifier keyEncAlgorithm, GenericKey contentEncryptionKey)
throws CMSException;
protected abstract ASN1Encodable getUserKeyingMaterial(AlgorithmIdentifier keyAgreeAlgorithm)
throws CMSException;
}
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