import org.bouncycastle.asn1.cms.RecipientIdentifier; //导入依赖的package包/类
KeyTransRecipientInformation(
    KeyTransRecipientInfo   info,
    AlgorithmIdentifier     messageAlgorithm,
    CMSSecureReadable       secureReadable,
    AuthAttributesProvider  additionalData)
{
    super(info.getKeyEncryptionAlgorithm(), messageAlgorithm, secureReadable, additionalData);

    this.info = info;

    RecipientIdentifier r = info.getRecipientIdentifier();

    if (r.isTagged())
    {
        ASN1OctetString octs = ASN1OctetString.getInstance(r.getId());

        rid = new KeyTransRecipientId(octs.getOctets());
    }
    else
    {
        IssuerAndSerialNumber   iAnds = IssuerAndSerialNumber.getInstance(r.getId());

        rid = new KeyTransRecipientId(iAnds.getName(), iAnds.getSerialNumber().getValue());
    }
}
 

import org.bouncycastle.asn1.cms.RecipientIdentifier; //导入依赖的package包/类
private KeyTransRecipientInfo computeRecipientInfo(X509Certificate x509certificate, byte[] abyte0)
    throws GeneralSecurityException, IOException
{
    ASN1InputStream asn1inputstream = 
        new ASN1InputStream(new ByteArrayInputStream(x509certificate.getTBSCertificate()));
    TBSCertificateStructure tbscertificatestructure = 
        TBSCertificateStructure.getInstance(asn1inputstream.readObject());
    AlgorithmIdentifier algorithmidentifier = tbscertificatestructure.getSubjectPublicKeyInfo().getAlgorithm();
    IssuerAndSerialNumber issuerandserialnumber = 
        new IssuerAndSerialNumber(
            tbscertificatestructure.getIssuer(), 
            tbscertificatestructure.getSerialNumber().getValue());
    Cipher cipher = Cipher.getInstance(algorithmidentifier.getAlgorithm().getId());        
    cipher.init(1, x509certificate);
    DEROctetString deroctetstring = new DEROctetString(cipher.doFinal(abyte0));
    RecipientIdentifier recipId = new RecipientIdentifier(issuerandserialnumber);
    return new KeyTransRecipientInfo( recipId, algorithmidentifier, deroctetstring);
}