+ * Credential charset is configured via the + * {@link ch.boye.httpclientandroidlib.auth.params.AuthPNames#CREDENTIAL_CHARSET} + * parameter of the HTTP request. + *
+ * Since the digest username is included as clear text in the generated + * Authentication header, the charset of the username must be compatible + * with the + * {@link ch.boye.httpclientandroidlib.params.CoreProtocolPNames#HTTP_ELEMENT_CHARSET + * http element charset}. + *
+ * The following parameters can be used to customize the behavior of this + * class: + *
digest
+ */
+ public String getSchemeName() {
+ return "digest";
+ }
+
+ /**
+ * Returns false. Digest authentication scheme is request based.
+ *
+ * @return false.
+ */
+ public boolean isConnectionBased() {
+ return false;
+ }
+
+ public void overrideParamter(final String name, final String value) {
+ getParameters().put(name, value);
+ }
+
+ /**
+ * Produces a digest authorization string for the given set of
+ * {@link Credentials}, method name and URI.
+ *
+ * @param credentials A set of credentials to be used for athentication
+ * @param request The request being authenticated
+ *
+ * @throws ch.boye.httpclientandroidlib.auth.InvalidCredentialsException if authentication credentials
+ * are not valid or not applicable for this authentication scheme
+ * @throws AuthenticationException if authorization string cannot
+ * be generated due to an authentication failure
+ *
+ * @return a digest authorization string
+ */
+ public Header authenticate(
+ final Credentials credentials,
+ final HttpRequest request) throws AuthenticationException {
+
+ if (credentials == null) {
+ throw new IllegalArgumentException("Credentials may not be null");
+ }
+ if (request == null) {
+ throw new IllegalArgumentException("HTTP request may not be null");
+ }
+
+ // Add method name and request-URI to the parameter map
+ getParameters().put("methodname", request.getRequestLine().getMethod());
+ getParameters().put("uri", request.getRequestLine().getUri());
+ String charset = getParameter("charset");
+ if (charset == null) {
+ charset = AuthParams.getCredentialCharset(request.getParams());
+ getParameters().put("charset", charset);
+ }
+ return createDigestHeader(credentials);
+ }
+
+ private static MessageDigest createMessageDigest(
+ final String digAlg) throws UnsupportedDigestAlgorithmException {
+ try {
+ return MessageDigest.getInstance(digAlg);
+ } catch (Exception e) {
+ throw new UnsupportedDigestAlgorithmException(
+ "Unsupported algorithm in HTTP Digest authentication: "
+ + digAlg);
+ }
+ }
+
+ /**
+ * Creates digest-response header as defined in RFC2617.
+ *
+ * @param credentials User credentials
+ *
+ * @return The digest-response as String.
+ */
+ private Header createDigestHeader(
+ final Credentials credentials) throws AuthenticationException {
+ String uri = getParameter("uri");
+ String realm = getParameter("realm");
+ String nonce = getParameter("nonce");
+ String opaque = getParameter("opaque");
+ String method = getParameter("methodname");
+ String algorithm = getParameter("algorithm");
+ if (uri == null) {
+ throw new IllegalStateException("URI may not be null");
+ }
+ if (realm == null) {
+ throw new IllegalStateException("Realm may not be null");
+ }
+ if (nonce == null) {
+ throw new IllegalStateException("Nonce may not be null");
+ }
+
+ //TODO: add support for QOP_INT
+ int qop = QOP_UNKNOWN;
+ String qoplist = getParameter("qop");
+ if (qoplist != null) {
+ StringTokenizer tok = new StringTokenizer(qoplist, ",");
+ while (tok.hasMoreTokens()) {
+ String variant = tok.nextToken().trim();
+ if (variant.equals("auth")) {
+ qop = QOP_AUTH;
+ break;
+ }
+ }
+ } else {
+ qop = QOP_MISSING;
+ }
+
+ if (qop == QOP_UNKNOWN) {
+ throw new AuthenticationException("None of the qop methods is supported: " + qoplist);
+ }
+
+ // If an algorithm is not specified, default to MD5.
+ if (algorithm == null) {
+ algorithm = "MD5";
+ }
+ // If an charset is not specified, default to ISO-8859-1.
+ String charset = getParameter("charset");
+ if (charset == null) {
+ charset = "ISO-8859-1";
+ }
+
+ String digAlg = algorithm;
+ if (digAlg.equalsIgnoreCase("MD5-sess")) {
+ digAlg = "MD5";
+ }
+
+ MessageDigest digester;
+ try {
+ digester = createMessageDigest(digAlg);
+ } catch (UnsupportedDigestAlgorithmException ex) {
+ throw new AuthenticationException("Unsuppported digest algorithm: " + digAlg);
+ }
+
+ String uname = credentials.getUserPrincipal().getName();
+ String pwd = credentials.getPassword();
+
+ if (nonce.equals(this.lastNonce)) {
+ nounceCount++;
+ } else {
+ nounceCount = 1;
+ cnonce = null;
+ lastNonce = nonce;
+ }
+ StringBuilder sb = new StringBuilder(256);
+ Formatter formatter = new Formatter(sb, Locale.US);
+ formatter.format("%08x", nounceCount);
+ String nc = sb.toString();
+
+ if (cnonce == null) {
+ cnonce = createCnonce();
+ }
+
+ a1 = null;
+ a2 = null;
+ // 3.2.2.2: Calculating digest
+ if (algorithm.equalsIgnoreCase("MD5-sess")) {
+ // H( unq(username-value) ":" unq(realm-value) ":" passwd )
+ // ":" unq(nonce-value)
+ // ":" unq(cnonce-value)
+
+ // calculated one per session
+ sb.setLength(0);
+ sb.append(uname).append(':').append(realm).append(':').append(pwd);
+ String checksum = encode(digester.digest(EncodingUtils.getBytes(sb.toString(), charset)));
+ sb.setLength(0);
+ sb.append(checksum).append(':').append(nonce).append(':').append(cnonce);
+ a1 = sb.toString();
+ } else {
+ // unq(username-value) ":" unq(realm-value) ":" passwd
+ sb.setLength(0);
+ sb.append(uname).append(':').append(realm).append(':').append(pwd);
+ a1 = sb.toString();
+ }
+
+ String hasha1 = encode(digester.digest(EncodingUtils.getBytes(a1, charset)));
+
+ if (qop == QOP_AUTH) {
+ // Method ":" digest-uri-value
+ a2 = method + ':' + uri;
+ } else if (qop == QOP_AUTH_INT) {
+ // Method ":" digest-uri-value ":" H(entity-body)
+ //TODO: calculate entity hash if entity is repeatable
+ throw new AuthenticationException("qop-int method is not suppported");
+ } else {
+ a2 = method + ':' + uri;
+ }
+
+ String hasha2 = encode(digester.digest(EncodingUtils.getBytes(a2, charset)));
+
+ // 3.2.2.1
+
+ String digestValue;
+ if (qop == QOP_MISSING) {
+ sb.setLength(0);
+ sb.append(hasha1).append(':').append(nonce).append(':').append(hasha2);
+ digestValue = sb.toString();
+ } else {
+ sb.setLength(0);
+ sb.append(hasha1).append(':').append(nonce).append(':').append(nc).append(':')
+ .append(cnonce).append(':').append(qop == QOP_AUTH_INT ? "auth-int" : "auth")
+ .append(':').append(hasha2);
+ digestValue = sb.toString();
+ }
+
+ String digest = encode(digester.digest(EncodingUtils.getAsciiBytes(digestValue)));
+
+ CharArrayBuffer buffer = new CharArrayBuffer(128);
+ if (isProxy()) {
+ buffer.append(AUTH.PROXY_AUTH_RESP);
+ } else {
+ buffer.append(AUTH.WWW_AUTH_RESP);
+ }
+ buffer.append(": Digest ");
+
+ ListString according to RFC 2617.
+ *
+ * @param binaryData array containing the digest
+ * @return encoded MD5, or null if encoding failed
+ */
+ private static String encode(byte[] binaryData) {
+ int n = binaryData.length;
+ char[] buffer = new char[n * 2];
+ for (int i = 0; i < n; i++) {
+ int low = (binaryData[i] & 0x0f);
+ int high = ((binaryData[i] & 0xf0) >> 4);
+ buffer[i * 2] = HEXADECIMAL[high];
+ buffer[(i * 2) + 1] = HEXADECIMAL[low];
+ }
+
+ return new String(buffer);
+ }
+
+
+ /**
+ * Creates a random cnonce value based on the current time.
+ *
+ * @return The cnonce value as String.
+ */
+ public static String createCnonce() {
+ SecureRandom rnd = new SecureRandom();
+ byte[] tmp = new byte[8];
+ rnd.nextBytes(tmp);
+ return encode(tmp);
+ }
+
+}