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   /*
    * Copyright 2002 Massachusetts Institute of Technology
    *   
    * Permission to use, copy, modify, and distribute this program for any
    * purpose and without fee is hereby granted, provided that this
    * copyright and permission notice appear on all copies and supporting
    * documentation, the name of M.I.T. not be used in advertising or
    * publicity pertaining to distribution of the program without specific
    * prior permission, and notice be given in supporting documentation that
   * copying and distribution is by permission of M.I.T.  M.I.T. makes no
   * representations about the suitability of this software for any
   * purpose.  It is provided "as is" without express or implied warranty.
   */
  package jsdsi;
  
  import java.io.FileReader;
  import java.io.IOException;
  import java.io.LineNumberReader;
  import java.math.BigInteger;
  import java.net.URI;
  import java.security.InvalidAlgorithmParameterException;
  import java.security.NoSuchAlgorithmException;
  import java.security.cert.CollectionCertStoreParameters;
  import java.util.Collection;
  import java.util.HashMap;
  import java.util.HashSet;
  import java.util.Map;
  import java.util.Set;
  import java.util.StringTokenizer;
  
  /***
   * <p>Creates a set of certificates from a flat text file for testing.
   * Each certificate appears on its own line.  Blank lines are allowed,
   * but comments are not.
   *
   * <p>Name certs are specified as follows:
   * <br><code>ISSUER name -> SUBJECT [names...]</code>
   * 
   * <p>For example,
   * <br><code>ALICE friends -> BOB</code>
   * <br><code>BOB my-friends -> BOB sister</code>
   * <br><code>BOB sister -> CAROL</code>
   *
   * <p>Note that we use uppercase for keys and lowercase for names for
   * clarity, but this is not required.  However, lines are
   * case-sensitive, so <code>"BOB"</code> is different from 
   * <code>"Bob"</code>.
   *
   * <p>Auth certs are specified as follows:
   * <br><code>ISSUER [!|+]tag -> SUBJECT [names...]</code>
   * <br>where ! means the permission <code>"tag"</code> cannot be 
   * delegated, while <code>"+"</code>
   * means that it can.
   *
   * <p>For example,
   * <br><code>ALICE !read -> BOB</code>
   * <br><code>BOB +write -> BOB my-friends</code>
   * 
   * @author Sameer Ajmani
   * @author Sean Radford
   * @version $Revision: 1.3 $ $Date: 2004/03/09 23:03:43 $
   */
  public class Loader {
  	/***
  	 * The keys.
  	 */
  	private Map keys = new HashMap();
  
  	/***
  	 * The certs.
  	 */
  	private Set certSet = new HashSet();
  
  	/***
  	 * The names.
  	 */
  	private Set nameSet = new HashSet();
  
  	/***
  	 * Thes tags.
  	 */
  	private Set tagSet = new HashSet();
  
  	/***
  	 * The cert store.
  	 */
  	private java.security.cert.CertStore store;
  
  	/***
  	 * Creates a new <code>Loader</code> from a given filename.
  	 * 
  	 * @param  filename filename to read the certificates from.
  	 * @throws IOException if an error occurs reading the file
  	 *         <code>filename</code>.
  	 */
  	public Loader(String filename) throws IOException {
  		Set certs = new HashSet();
  		LineNumberReader in = new LineNumberReader(new FileReader(filename));
  		in.setLineNumber(1);
 		for (String line = in.readLine(); line != null; line = in.readLine()) {
 			StringTokenizer t = new StringTokenizer(line);
 			if (t.countTokens() == 0) {
 				continue; // skip empty lines
 			}
 			if (t.countTokens() < 4) {
 				throw new IOException(
 					"bad input on line " + in.getLineNumber() + ": " + line);
 			}
 			Principal issuer = getPrincipal(t.nextToken());
 			String name = t.nextToken();
 			String arrow = t.nextToken();
 			if (!arrow.equals("->")) {
 				throw new IOException(
 					"bad arrow on line " + in.getLineNumber() + ": " + line);
 			}
 			Principal sub = getPrincipal(t.nextToken());
 			String[] names = new String[t.countTokens()];
 			for (int i = 0; i < names.length; i++) {
 				names[i] = t.nextToken();
 			}
 			Subject subject =
 				(names.length > 0)
 					? (Subject) new Name(sub, names)
 					: (Subject) sub;
 
 			// create a fake certificate with a fake signature
 			Cert c;
 			if (name.startsWith("!") || name.startsWith("+")) {
 				// this is an auth cert
 				Tag tag = new StringTag(name.substring(1));
 				tagSet.add(tag);
 				c =
 					new AuthCert(
 						issuer,
 						subject,
 						null,
 						null,
 						null,
 						tag,
 						name.startsWith("+"));
 				// propagate?
 			} else {
 				// this is a name cert
 				nameSet.add(new Name(issuer, name));
 				c = new NameCert(issuer, subject, null, null, null, name);
 			}
 			certSet.add(c);
 			Signature s =
 				new Signature(
 					issuer,
 					new Hash("md5", "HASH-VALUE".getBytes(), null),
 					"rsa-pkcs1-md5",
 					"SIGNATURE-VALUE".getBytes());
 			try {
 				certs.add(new Certificate(c, s));
 			} catch (java.security.cert.CertificateException e) {
 				throw new Error(e);
 			}
 		}
 		try {
 			store =
 				java.security.cert.CertStore.getInstance(
 					"SPKI",
 					new CollectionCertStoreParameters(certs));
 		} catch (InvalidAlgorithmParameterException e) {
 			throw new Error(e);
 		} catch (NoSuchAlgorithmException e) {
 			throw new Error(e);
 		}
 	}
 
 	/***
 	 * Returns the cert store of this <code>Loader</code>.
 	 * 
 	 * @return the cert store of this <code>Loader</code>.
 	 */
 	public java.security.cert.CertStore getCertStore() {
 		return store;
 	}
 
 	/***
 	 * Returns the keys of this <code>Loader</code>.
 	 * 
 	 * @return the keys of this <code>Loader</code>.
 	 */
 	public Collection getKeys() {
 		return keys.values();
 	}
 
 	/***
 	 * Returns the certs of this <code>Loader</code>.
 	 * 
 	 * @return the certs of this <code>Loader</code>.
 	 */
 	public Set getCerts() {
 		return certSet;
 	}
 
 	/***
 	 * Returns the names of this <code>Loader</code>.
 	 * 
 	 * @return the names of this <code>Loader</code>.
 	 */
 	public Set getNames() {
 		return nameSet;
 	}
 
 	/***
 	 * Returns the tags of this <code>Loader</code>.
 	 * 
 	 * @return the tags of this <code>Loader</code>.
 	 */
 	public Set getTags() {
 		return tagSet;
 	}
 
 	/***
 	 * For a given string: looks if the key is already saved in the loader
 	 * or creates a new one from the bytes stored in the given key (assuming
 	 * <code>MD5/RSA/PKCS#1</code> format).
 	 * 
 	 * @param  id key to add to the keys of this <code>Loader</code> if not 
 	 *         already stored (assumes <code>MD5/RSA/PKCS#1</code> format).
 	 * @return either the key already stored or the new key added to the keys.
 	 */
 	private Principal getPrincipal(String id) {
 		RSAPublicKey k = (RSAPublicKey) keys.get(id);
 		if (k == null) {
 			k =
 				new RSAPublicKey(
 					new BigInteger(id.getBytes()),
 					new BigInteger(new byte[] { 0x03 }),
 					"MD5/RSA/PKCS#1",
 					(URI[])null);
 			keys.put(id, k);
 		}
 		return k;
 	}
 }