| /* |
| * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.security; |
| |
| import java.io.*; |
| |
| /** |
| * <p> SignedObject is a class for the purpose of creating authentic |
| * runtime objects whose integrity cannot be compromised without being |
| * detected. |
| * |
| * <p> More specifically, a SignedObject contains another Serializable |
| * object, the (to-be-)signed object and its signature. |
| * |
| * <p> The signed object is a "deep copy" (in serialized form) of an |
| * original object. Once the copy is made, further manipulation of |
| * the original object has no side effect on the copy. |
| * |
| * <p> The underlying signing algorithm is designated by the Signature |
| * object passed to the constructor and the <code>verify</code> method. |
| * A typical usage for signing is the following: |
| * |
| * <p> <code> <pre> |
| * Signature signingEngine = Signature.getInstance(algorithm, |
| * provider); |
| * SignedObject so = new SignedObject(myobject, signingKey, |
| * signingEngine); |
| * </pre> </code> |
| * |
| * <p> A typical usage for verification is the following (having |
| * received SignedObject <code>so</code>): |
| * |
| * <p> <code> <pre> |
| * Signature verificationEngine = |
| * Signature.getInstance(algorithm, provider); |
| * if (so.verify(publickey, verificationEngine)) |
| * try { |
| * Object myobj = so.getObject(); |
| * } catch (java.lang.ClassNotFoundException e) {}; |
| * </pre> </code> |
| * |
| * <p> Several points are worth noting. First, there is no need to |
| * initialize the signing or verification engine, as it will be |
| * re-initialized inside the constructor and the <code>verify</code> |
| * method. Secondly, for verification to succeed, the specified |
| * public key must be the public key corresponding to the private key |
| * used to generate the SignedObject. |
| * |
| * <p> More importantly, for flexibility reasons, the |
| * constructor and <code>verify</code> method allow for |
| * customized signature engines, which can implement signature |
| * algorithms that are not installed formally as part of a crypto |
| * provider. However, it is crucial that the programmer writing the |
| * verifier code be aware what <code>Signature</code> engine is being |
| * used, as its own implementation of the <code>verify</code> method |
| * is invoked to verify a signature. In other words, a malicious |
| * <code>Signature</code> may choose to always return true on |
| * verification in an attempt to bypass a security check. |
| * |
| * <p> The signature algorithm can be, among others, the NIST standard |
| * DSA, using DSA and SHA-1. The algorithm is specified using the |
| * same convention as that for signatures. The DSA algorithm using the |
| * SHA-1 message digest algorithm can be specified, for example, as |
| * "SHA/DSA" or "SHA-1/DSA" (they are equivalent). In the case of |
| * RSA, there are multiple choices for the message digest algorithm, |
| * so the signing algorithm could be specified as, for example, |
| * "MD2/RSA", "MD5/RSA" or "SHA-1/RSA". The algorithm name must be |
| * specified, as there is no default. |
| * |
| * <p> The name of the Cryptography Package Provider is designated |
| * also by the Signature parameter to the constructor and the |
| * <code>verify</code> method. If the provider is not |
| * specified, the default provider is used. Each installation can |
| * be configured to use a particular provider as default. |
| * |
| * <p> Potential applications of SignedObject include: |
| * <ul> |
| * <li> It can be used |
| * internally to any Java runtime as an unforgeable authorization |
| * token -- one that can be passed around without the fear that the |
| * token can be maliciously modified without being detected. |
| * <li> It |
| * can be used to sign and serialize data/object for storage outside |
| * the Java runtime (e.g., storing critical access control data on |
| * disk). |
| * <li> Nested SignedObjects can be used to construct a logical |
| * sequence of signatures, resembling a chain of authorization and |
| * delegation. |
| * </ul> |
| * |
| * @see Signature |
| * |
| * @author Li Gong |
| */ |
| |
| public final class SignedObject implements Serializable { |
| |
| private static final long serialVersionUID = 720502720485447167L; |
| |
| /* |
| * The original content is "deep copied" in its serialized format |
| * and stored in a byte array. The signature field is also in the |
| * form of byte array. |
| */ |
| |
| private byte[] content; |
| private byte[] signature; |
| private String thealgorithm; |
| |
| /** |
| * Constructs a SignedObject from any Serializable object. |
| * The given object is signed with the given signing key, using the |
| * designated signature engine. |
| * |
| * @param object the object to be signed. |
| * @param signingKey the private key for signing. |
| * @param signingEngine the signature signing engine. |
| * |
| * @exception IOException if an error occurs during serialization |
| * @exception InvalidKeyException if the key is invalid. |
| * @exception SignatureException if signing fails. |
| */ |
| public SignedObject(Serializable object, PrivateKey signingKey, |
| Signature signingEngine) |
| throws IOException, InvalidKeyException, SignatureException { |
| // creating a stream pipe-line, from a to b |
| ByteArrayOutputStream b = new ByteArrayOutputStream(); |
| ObjectOutput a = new ObjectOutputStream(b); |
| |
| // write and flush the object content to byte array |
| a.writeObject(object); |
| a.flush(); |
| a.close(); |
| this.content = b.toByteArray(); |
| b.close(); |
| |
| // now sign the encapsulated object |
| this.sign(signingKey, signingEngine); |
| } |
| |
| /** |
| * Retrieves the encapsulated object. |
| * The encapsulated object is de-serialized before it is returned. |
| * |
| * @return the encapsulated object. |
| * |
| * @exception IOException if an error occurs during de-serialization |
| * @exception ClassNotFoundException if an error occurs during |
| * de-serialization |
| */ |
| public Object getObject() |
| throws IOException, ClassNotFoundException |
| { |
| // creating a stream pipe-line, from b to a |
| ByteArrayInputStream b = new ByteArrayInputStream(this.content); |
| ObjectInput a = new ObjectInputStream(b); |
| Object obj = a.readObject(); |
| b.close(); |
| a.close(); |
| return obj; |
| } |
| |
| /** |
| * Retrieves the signature on the signed object, in the form of a |
| * byte array. |
| * |
| * @return the signature. Returns a new array each time this |
| * method is called. |
| */ |
| public byte[] getSignature() { |
| return this.signature.clone(); |
| } |
| |
| /** |
| * Retrieves the name of the signature algorithm. |
| * |
| * @return the signature algorithm name. |
| */ |
| public String getAlgorithm() { |
| return this.thealgorithm; |
| } |
| |
| /** |
| * Verifies that the signature in this SignedObject is the valid |
| * signature for the object stored inside, with the given |
| * verification key, using the designated verification engine. |
| * |
| * @param verificationKey the public key for verification. |
| * @param verificationEngine the signature verification engine. |
| * |
| * @exception SignatureException if signature verification failed. |
| * @exception InvalidKeyException if the verification key is invalid. |
| * |
| * @return <tt>true</tt> if the signature |
| * is valid, <tt>false</tt> otherwise |
| */ |
| public boolean verify(PublicKey verificationKey, |
| Signature verificationEngine) |
| throws InvalidKeyException, SignatureException { |
| verificationEngine.initVerify(verificationKey); |
| verificationEngine.update(this.content.clone()); |
| return verificationEngine.verify(this.signature.clone()); |
| } |
| |
| /* |
| * Signs the encapsulated object with the given signing key, using the |
| * designated signature engine. |
| * |
| * @param signingKey the private key for signing. |
| * @param signingEngine the signature signing engine. |
| * |
| * @exception InvalidKeyException if the key is invalid. |
| * @exception SignatureException if signing fails. |
| */ |
| private void sign(PrivateKey signingKey, Signature signingEngine) |
| throws InvalidKeyException, SignatureException { |
| // initialize the signing engine |
| signingEngine.initSign(signingKey); |
| signingEngine.update(this.content.clone()); |
| this.signature = signingEngine.sign().clone(); |
| this.thealgorithm = signingEngine.getAlgorithm(); |
| } |
| |
| /** |
| * readObject is called to restore the state of the SignedObject from |
| * a stream. |
| */ |
| private void readObject(java.io.ObjectInputStream s) |
| throws java.io.IOException, ClassNotFoundException { |
| java.io.ObjectInputStream.GetField fields = s.readFields(); |
| content = ((byte[])fields.get("content", null)).clone(); |
| signature = ((byte[])fields.get("signature", null)).clone(); |
| thealgorithm = (String)fields.get("thealgorithm", null); |
| } |
| } |
