public org.bouncycastle.tsp.TimeStampResponse timestampData(byte[] digest) throws IOException {

        String TSA_URL = conf.getTspServerAddress(); // "http://www.cryptopro.ru/tsp/tsp.srf"

        try {
            TimeStampRequestGenerator reqgen = new TimeStampRequestGenerator();
            TimeStampRequest req = reqgen.generate(TSPAlgorithms.GOST3411, digest);
            
            byte request[] = req.getEncoded();

            URL url = new URL(TSA_URL);
            HttpURLConnection con = (HttpURLConnection) url.openConnection();

            con.setDoOutput(true);
            con.setDoInput(true);
            con.setRequestMethod("POST");
            con.setRequestProperty("Content-type", "application/timestamp-query");
            con.setRequestProperty("Content-length", String.valueOf(request.length));
            OutputStream out = con.getOutputStream();
            try {
                out.write(request);
                out.flush();
            } finally {
                out.close();
            }

            if (con.getResponseCode() != HttpURLConnection.HTTP_OK) {
                throw new IOException("Received HTTP error: " + con.getResponseCode() + " - " + con.getResponseMessage());
            }
            InputStream in = con.getInputStream();
            TimeStampResp resp = TimeStampResp.getInstance(new ASN1InputStream(in).readObject());
            TimeStampResponse response = new TimeStampResponse(resp);
            response.validate(req);
            System.out.println(response.getTimeStampToken().getTimeStampInfo().getGenTime());
            return response;
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

TimeStampRequestGenerator reqgen = new TimeStampRequestGenerator();
BigInteger nonce = BigInteger.valueOf(System.currentTimeMillis());

// imprint - хеш данных, hashAlg - OID алгоритма хеширования
TimeStampRequest req = reqgen.generate(hashAlg, imprint, nonce);
byte request[] = req.getEncoded();

MessageDigest messageDigest = MessageDigest.getInstance(hashAlg);
messageDigest.update(signature, 0, signature.length);
byte[] imprint = messageDigest.digest();