http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5. 
package org.bouncycastle.asn1.smime;

import org.bouncycastle.asn1.DERObjectIdentifier;
import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;

public interface SMIMEAttributes
{
    public static final DERObjectIdentifier  smimeCapabilities = PKCSObjectIdentifiers.pkcs_9_at_smimeCapabilities;
    public static final DERObjectIdentifier  encrypKeyPref = PKCSObjectIdentifiers.id_aa_encrypKeyPref;
}