package org.bouncycastle.cms;
import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.security.AlgorithmParameters;
import java.security.NoSuchProviderException;
import java.security.Provider;
import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1OctetStringParser;
import org.bouncycastle.asn1.ASN1SequenceParser;
import org.bouncycastle.asn1.ASN1Set;
import org.bouncycastle.asn1.ASN1SetParser;
import org.bouncycastle.asn1.DEREncodable;
import org.bouncycastle.asn1.DERSet;
import org.bouncycastle.asn1.DERTags;
import org.bouncycastle.asn1.cms.AttributeTable;
import org.bouncycastle.asn1.cms.EncryptedContentInfoParser;
import org.bouncycastle.asn1.cms.EnvelopedDataParser;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
/**
* Parsing class for an CMS Enveloped Data object from an input stream.
* <p>
* Note: that because we are in a streaming mode only one recipient can be tried and it is important
* that the methods on the parser are called in the appropriate order.
* </p>
* <p>
* Example of use - assuming the first recipient matches the private key we have.
* <pre>
* CMSEnvelopedDataParser ep = new CMSEnvelopedDataParser(inputStream);
*
* RecipientInformationStore recipients = ep.getRecipientInfos();
*
* Collection c = recipients.getRecipients();
* Iterator it = c.iterator();
*
* if (it.hasNext())
* {
* RecipientInformation recipient = (RecipientInformation)it.next();
*
* CMSTypedStream recData = recipient.getContentStream(new JceKeyTransEnvelopedRecipient(privateKey).setProvider("BC"));
*
* processDataStream(recData.getContentStream());
* }
* </pre>
* Note: this class does not introduce buffering - if you are processing large files you should create
* the parser with:
* <pre>
* CMSEnvelopedDataParser ep = new CMSEnvelopedDataParser(new BufferedInputStream(inputStream, bufSize));
* </pre>
* where bufSize is a suitably large buffer size.
*/
public class CMSEnvelopedDataParser
extends CMSContentInfoParser
{
RecipientInformationStore _recipientInfoStore;
EnvelopedDataParser _envelopedData;
private AlgorithmIdentifier _encAlg;
private AttributeTable _unprotectedAttributes;
private boolean _attrNotRead;
public CMSEnvelopedDataParser(
byte[] envelopedData)
throws CMSException, IOException
{
this(new ByteArrayInputStream(envelopedData));
}
public CMSEnvelopedDataParser(
InputStream envelopedData)
throws CMSException, IOException
{
super(envelopedData);
this._attrNotRead = true;
this._envelopedData = new EnvelopedDataParser((ASN1SequenceParser)_contentInfo.getContent(DERTags.SEQUENCE));
// TODO Validate version?
//DERInteger version = this._envelopedData.getVersion();
//
// read the recipients
//
ASN1Set recipientInfos = ASN1Set.getInstance(_envelopedData.getRecipientInfos().getDERObject());
//
// read the encrypted content info
//
EncryptedContentInfoParser encInfo = _envelopedData.getEncryptedContentInfo();
this._encAlg = encInfo.getContentEncryptionAlgorithm();
CMSReadable readable = new CMSProcessableInputStream(
((ASN1OctetStringParser)encInfo.getEncryptedContent(DERTags.OCTET_STRING)).getOctetStream());
CMSSecureReadable secureReadable = new CMSEnvelopedHelper.CMSEnvelopedSecureReadable(
this._encAlg, readable);
//
// build the RecipientInformationStore
//
this._recipientInfoStore = CMSEnvelopedHelper.buildRecipientInformationStore(
recipientInfos, this._encAlg, secureReadable);
}
/**
* return the object identifier for the content encryption algorithm.
*/
public String getEncryptionAlgOID()
{
return _encAlg.getObjectId().toString();
}
/**
* return the ASN.1 encoded encryption algorithm parameters, or null if
* there aren't any.
*/
public byte[] getEncryptionAlgParams()
{
try
{
return encodeObj(_encAlg.getParameters());
}
catch (Exception e)
{
throw new RuntimeException("exception getting encryption parameters " + e);
}
}
/**
* Return an AlgorithmParameters object giving the encryption parameters
* used to encrypt the message content.
*
* @param provider the name of the provider to generate the parameters for.
* @return the parameters object, null if there is not one.
* @throws CMSException if the algorithm cannot be found, or the parameters can't be parsed.
* @throws NoSuchProviderException if the provider cannot be found.
*/
public AlgorithmParameters getEncryptionAlgorithmParameters(
String provider)
throws CMSException, NoSuchProviderException
{
return getEncryptionAlgorithmParameters(CMSUtils.getProvider(provider));
}
/**
* Return an AlgorithmParameters object giving the encryption parameters
* used to encrypt the message content.
*
* @param provider the provider to generate the parameters for.
* @return the parameters object, null if there is not one.
* @throws CMSException if the algorithm cannot be found, or the parameters can't be parsed.
*/
public AlgorithmParameters getEncryptionAlgorithmParameters(
Provider provider)
throws CMSException
{
return CMSEnvelopedHelper.INSTANCE.getEncryptionAlgorithmParameters(getEncryptionAlgOID(), getEncryptionAlgParams(), provider);
}
/**
* return a store of the intended recipients for this message
*/
public RecipientInformationStore getRecipientInfos()
{
return _recipientInfoStore;
}
/**
* return a table of the unprotected attributes indexed by
* the OID of the attribute.
* @exception IOException
*/
public AttributeTable getUnprotectedAttributes()
throws IOException
{
if (_unprotectedAttributes == null && _attrNotRead)
{
ASN1SetParser set = _envelopedData.getUnprotectedAttrs();
_attrNotRead = false;
if (set != null)
{
ASN1EncodableVector v = new ASN1EncodableVector();
DEREncodable o;
while ((o = set.readObject()) != null)
{
ASN1SequenceParser seq = (ASN1SequenceParser)o;
v.add(seq.getDERObject());
}
_unprotectedAttributes = new AttributeTable(new DERSet(v));
}
}
return _unprotectedAttributes;
}
private byte[] encodeObj(
DEREncodable obj)
throws IOException
{
if (obj != null)
{
return obj.getDERObject().getEncoded();
}
return null;
}
}