private DERObject createDERForRecipient(byte[] in, X509Certificate cert)
throws IOException, GeneralSecurityException {
String s = "1.2.840.113549.3.2";
AlgorithmParameterGenerator algorithmparametergenerator =
AlgorithmParameterGenerator.getInstance(s);
AlgorithmParameters algorithmparameters = algorithmparametergenerator.generateParameters();
ByteArrayInputStream bytearrayinputstream =
new ByteArrayInputStream(algorithmparameters.getEncoded("ASN.1"));
ASN1InputStream asn1inputstream = new ASN1InputStream(bytearrayinputstream);
DERObject derobject = asn1inputstream.readObject();
KeyGenerator keygenerator = KeyGenerator.getInstance(s);
keygenerator.init(128);
SecretKey secretkey = keygenerator.generateKey();
Cipher cipher = Cipher.getInstance(s);
cipher.init(1, secretkey, algorithmparameters);
byte[] abyte1 = cipher.doFinal(in);
DEROctetString deroctetstring = new DEROctetString(abyte1);
KeyTransRecipientInfo keytransrecipientinfo =
computeRecipientInfo(cert, secretkey.getEncoded());
DERSet derset = new DERSet(new RecipientInfo(keytransrecipientinfo));
AlgorithmIdentifier algorithmidentifier =
new AlgorithmIdentifier(new DERObjectIdentifier(s), derobject);
EncryptedContentInfo encryptedcontentinfo =
new EncryptedContentInfo(PKCSObjectIdentifiers.data, algorithmidentifier, deroctetstring);
EnvelopedData env = new EnvelopedData(null, derset, encryptedcontentinfo, null);
ContentInfo contentinfo = new ContentInfo(PKCSObjectIdentifiers.envelopedData, env);
return contentinfo.getDERObject();
}
