prng.internet.Quantum Maven / Gradle / Ivy

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The core random number generators
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package prng.internet;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.StandardCharsets;
import prng.internet.SimpleJSONParser.JSONArray;
import prng.internet.SimpleJSONParser.JSONObject;
import prng.internet.SimpleJSONParser.Primitive;
import prng.internet.SimpleJSONParser.Type;
import prng.utility.BLOBPrint;

/**
 * Source that fetches from the ANU QRNG service. Note that although the ANU QRNG service offers an HTTPS API, the HTTPS certificates contain forbidden
 * extensions and therefore do not validate.
 *
 * @author Simon Greatrix
 */
public class Quantum extends NetRandom {

  /** Service URL */
  private static final URL QRNG;

  static {
    try {
      QRNG = new URL("https://qrng.anu.edu.au/API/jsonI.php?length=128&size=1&type=uint8");
    } catch (MalformedURLException e) {
      throw new Error("Impossible exception", e);
    }
  }


  /**
   * Read data from the Australian National University Quantum Random Number Generator.
   *
   * @return the bits
   * @throws IOException if communication with the service fails
   */
  @Override
  byte[] fetch() throws IOException {
    HttpURLConnection conn = connect(QRNG);
    byte[] data;
    try {
      data = read(conn);
    } finally {
      conn.disconnect();
    }

    try {
      // convert response to JSON
      Primitive result = SimpleJSONParser.parse(
          new InputStreamReader(new ByteArrayInputStream(data),
              StandardCharsets.ISO_8859_1));
      if (result.getType() != Type.OBJECT) {
        throw new IOException(QRNG.getHost() + " returned JSON type: "
            + result.getType());
      }
      JSONObject obj = result.getValueSafe(JSONObject.class);

      // response will indicate success
      if (!obj.get(Boolean.class, "success",
          Boolean.FALSE).booleanValue()) {
        throw new IOException(
            QRNG.getHost() + " did not indicate success");
      }

      // if successful, should contain data array
      JSONArray arr = obj.get(JSONArray.class, "data", null);
      if (arr == null) {
        throw new IOException(QRNG.getHost() + " did not return data");
      }
      if (arr.size() != 128) {
        throw new IOException(QRNG.getHost() + " returned " + arr.size()
            + " bytes not 128");
      }

      // load data into array
      byte[] bits = new byte[128];
      int pos = 0;
      for (Primitive prim : arr) {
        Integer val = prim.getValue(Integer.class, null);
        if (val == null) {
          throw new IOException(
              QRNG.getHost() + " sent data of " + prim.getType()
                  + ": " + prim + " which is not an integer");
        }
        bits[pos] = val.byteValue();
        pos++;
      }

      // done, return data
      return bits;
    } catch (IOException ioe) {
      LOG.error("Bad data received from {}\n\n{}", QRNG.getHost(),
          BLOBPrint.toString(data));
      throw ioe;
    }
  }


  @Override
  URL url() {
    return QRNG;
  }
}