http://www.bouncycastle.org/java.html: The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. This jar contains APIs for JDK 1.5 to JDK 1.8. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs.
  • The Legion of the Bouncy Castle Inc. 
package org.bouncycastle.cms;

import java.io.IOException;
import java.io.InputStream;

import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.cms.CompressedData;
import org.bouncycastle.asn1.cms.ContentInfo;
import org.bouncycastle.operator.InputExpander;
import org.bouncycastle.operator.InputExpanderProvider;
import org.bouncycastle.util.Encodable;


containing class for an CMS Compressed Data object

    CMSCompressedData cd = new CMSCompressedData(inputStream);
    process(cd.getContent(new ZlibExpanderProvider()));



/**
 * containing class for an CMS Compressed Data object
 * <pre>
 *     CMSCompressedData cd = new CMSCompressedData(inputStream);
 *
 *     process(cd.getContent(new ZlibExpanderProvider()));
 * </pre>
 */
public class CMSCompressedData
    implements Encodable
{
    ContentInfo                 contentInfo;
    CompressedData              comData;

    public CMSCompressedData(
        byte[]    compressedData) 
        throws CMSException
    {
        this(CMSUtils.readContentInfo(compressedData));
    }

    public CMSCompressedData(
        InputStream    compressedData) 
        throws CMSException
    {
        this(CMSUtils.readContentInfo(compressedData));
    }

    public CMSCompressedData(
        ContentInfo contentInfo)
        throws CMSException
    {
        this.contentInfo = contentInfo;

        try
        {
            this.comData = CompressedData.getInstance(contentInfo.getContent());
        }
        catch (ClassCastException e)
        {
            throw new CMSException("Malformed content.", e);
        }
        catch (IllegalArgumentException e)
        {
            throw new CMSException("Malformed content.", e);
        }
    }

    public ASN1ObjectIdentifier getContentType()
    {
        return contentInfo.getContentType();
    }

    
Return the uncompressed content.

Params:
  • expanderProvider – a provider of expander algorithm implementations.
Throws:
  • CMSException – if there is an exception un-compressing the data.
Returns:the uncompressed content
/**
     * Return the uncompressed content.
     *
     * @param expanderProvider a provider of expander algorithm implementations.
     * @return the uncompressed content
     * @throws CMSException if there is an exception un-compressing the data.
     */
    public byte[] getContent(InputExpanderProvider expanderProvider)
        throws CMSException
    {
        ContentInfo     content = comData.getEncapContentInfo();

        ASN1OctetString bytes = (ASN1OctetString)content.getContent();
        InputExpander   expander = expanderProvider.get(comData.getCompressionAlgorithmIdentifier());
        InputStream     zIn = expander.getInputStream(bytes.getOctetStream());

        try
        {
            return CMSUtils.streamToByteArray(zIn);
        }
        catch (IOException e)
        {
            throw new CMSException("exception reading compressed stream.", e);
        }
    }

    
return the ContentInfo

/**
     * return the ContentInfo
     */
    public ContentInfo toASN1Structure()
    {
        return contentInfo;
    }
    
    
return the ASN.1 encoded representation of this object.

/**
     * return the ASN.1 encoded representation of this object.
     */
    public byte[] getEncoded()
        throws IOException
    {
        return contentInfo.getEncoded();
    }
}