protected byte[] decrypt(final byte[] data, final PrivateKey responderKey) throws Exception {
        Asn1BerDecodeBuffer dbuf = new Asn1BerDecodeBuffer(data);
        final ContentInfo all = new ContentInfo();
        all.decode(dbuf);
        dbuf.reset();
        final EnvelopedData cms = (EnvelopedData) all.content;

        KeyTransRecipientInfo keytrans = new KeyTransRecipientInfo();
        if (cms.recipientInfos.elements[0].getChoiceID() == RecipientInfo._KTRI)
            keytrans =
                    (KeyTransRecipientInfo) (cms.recipientInfos.elements[0].getElement());
        final Asn1BerEncodeBuffer ebuf = new Asn1BerEncodeBuffer();
        dbuf = new Asn1BerDecodeBuffer(keytrans.encryptedKey.value);
        final GostR3410_KeyTransport encrKey = new GostR3410_KeyTransport();
        encrKey.decode(dbuf);
        dbuf.reset();
        encrKey.sessionEncryptedKey.encode(ebuf);
        final byte[] wrapKey = ebuf.getMsgCopy();
        ebuf.reset();
        encrKey.transportParameters.ephemeralPublicKey.encode(ebuf);
        final byte[] encodedPub = ebuf.getMsgCopy();
        ebuf.reset();
        final byte[] sv = encrKey.transportParameters.ukm.value;
        final Gost28147_89_Parameters params =
                (Gost28147_89_Parameters) cms.encryptedContentInfo.contentEncryptionAlgorithm.parameters;
        final byte[] iv = params.iv.value;
        final OID cipherOID = new OID(params.encryptionParamSet.value);
        final byte[] text = cms.encryptedContentInfo.encryptedContent.value;

        //отправитель - открытый ключ из cms
        final X509EncodedKeySpec pspec = new X509EncodedKeySpec(encodedPub);
        final KeyFactory kf = KeyFactory.getInstance(JCP.GOST_DH_NAME);
        final PublicKey senderPublic = kf.generatePublic(pspec);

        // выработка ключа согласования получателем
        final KeyAgreement responderKeyAgree =
                KeyAgreement.getInstance(JCP.GOST_DH_NAME, CryptoProvider.PROVIDER_NAME);
        responderKeyAgree.init(responderKey, new IvParameterSpec(sv), null);
        responderKeyAgree.doPhase(senderPublic, true);
        final SecretKey responderSecret = responderKeyAgree
                .generateSecret("GOST28147");

        // Расшифрование симметричного ключа.
        final Cipher cipher = Cipher.getInstance(CIPHER_MODE, CryptoProvider.PROVIDER_NAME);
        cipher.init(Cipher.UNWRAP_MODE, responderSecret, (SecureRandom) null);
        //cipher.init(Cipher.UNWRAP_MODE, responderSecret);
        final SecretKey simmKey = (SecretKey) cipher.unwrap(wrapKey, null, Cipher.SECRET_KEY);

        // Расшифрование текста на симметричном ключе.
        final GostCipherSpec spec = new GostCipherSpec(iv, cipherOID);
        cipher.init(Cipher.DECRYPT_MODE, simmKey, spec, null);
        return cipher.doFinal(text, 0, text.length);
    }