| /* RSAPSSSignature.java -- |
| Copyright (C) 2001, 2002, 2003, 2006, 2010 Free Software Foundation, Inc. |
| |
| This file is a part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2 of the License, or (at |
| your option) any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 |
| USA |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| |
| package gnu.java.security.sig.rsa; |
| |
| import gnu.java.security.Configuration; |
| import gnu.java.security.Registry; |
| import gnu.java.security.hash.HashFactory; |
| import gnu.java.security.hash.IMessageDigest; |
| import gnu.java.security.sig.BaseSignature; |
| import gnu.java.security.util.Util; |
| |
| import java.math.BigInteger; |
| import java.security.PrivateKey; |
| import java.security.PublicKey; |
| import java.security.interfaces.RSAPrivateKey; |
| import java.security.interfaces.RSAPublicKey; |
| import java.util.logging.Logger; |
| |
| /** |
| * The RSA-PSS signature scheme is a public-key encryption scheme combining the |
| * RSA algorithm with the Probabilistic Signature Scheme (PSS) encoding method. |
| * <p> |
| * The inventors of RSA are Ronald L. Rivest, Adi Shamir, and Leonard Adleman, |
| * while the inventors of the PSS encoding method are Mihir Bellare and Phillip |
| * Rogaway. During efforts to adopt RSA-PSS into the P1363a standards effort, |
| * certain adaptations to the original version of RSA-PSS were made by Mihir |
| * Bellare and Phillip Rogaway and also by Burt Kaliski (the editor of IEEE |
| * P1363a) to facilitate implementation and integration into existing protocols. |
| * <p> |
| * References: |
| * <ol> |
| * <li><a |
| * href="http://www.cosic.esat.kuleuven.ac.be/nessie/workshop/submissions/rsa-pss.zip"> |
| * RSA-PSS Signature Scheme with Appendix, part B.</a><br> |
| * Primitive specification and supporting documentation.<br> |
| * Jakob Jonsson and Burt Kaliski.</li> |
| * </ol> |
| */ |
| public class RSAPSSSignature |
| extends BaseSignature |
| { |
| private static final Logger log = Configuration.DEBUG ? |
| Logger.getLogger(RSAPSSSignature.class.getName()) : null; |
| |
| /** The underlying EMSA-PSS instance for this object. */ |
| private EMSA_PSS pss; |
| |
| /** The desired length in octets of the EMSA-PSS salt. */ |
| private int sLen; |
| |
| /** |
| * Default 0-arguments constructor. Uses SHA-1 as the default hash and a |
| * 0-octet <i>salt</i>. |
| */ |
| public RSAPSSSignature() |
| { |
| this(Registry.SHA160_HASH, 0); |
| } |
| |
| /** |
| * Constructs an instance of this object using the designated message digest |
| * algorithm as its underlying hash function, and having 0-octet <i>salt</i>. |
| * |
| * @param mdName the canonical name of the underlying hash function. |
| */ |
| public RSAPSSSignature(String mdName) |
| { |
| this(mdName, 0); |
| } |
| |
| /** |
| * Constructs an instance of this object using the designated message digest |
| * algorithm as its underlying hash function. |
| * |
| * @param mdName the canonical name of the underlying hash function. |
| * @param sLen the desired length in octets of the salt to use for encoding / |
| * decoding signatures. |
| */ |
| public RSAPSSSignature(String mdName, int sLen) |
| { |
| this(HashFactory.getInstance(mdName), sLen); |
| } |
| |
| public RSAPSSSignature(IMessageDigest md, int sLen) |
| { |
| super(Registry.RSA_PSS_SIG, md); |
| |
| pss = EMSA_PSS.getInstance(md.name()); |
| this.sLen = sLen; |
| } |
| |
| /** Private constructor for cloning purposes. */ |
| private RSAPSSSignature(RSAPSSSignature that) |
| { |
| this(that.md.name(), that.sLen); |
| |
| this.publicKey = that.publicKey; |
| this.privateKey = that.privateKey; |
| this.md = (IMessageDigest) that.md.clone(); |
| this.pss = (EMSA_PSS) that.pss.clone(); |
| } |
| |
| public Object clone() |
| { |
| return new RSAPSSSignature(this); |
| } |
| |
| protected void setupForVerification(PublicKey k) |
| throws IllegalArgumentException |
| { |
| if (! (k instanceof RSAPublicKey)) |
| throw new IllegalArgumentException(); |
| |
| publicKey = (RSAPublicKey) k; |
| } |
| |
| protected void setupForSigning(PrivateKey k) throws IllegalArgumentException |
| { |
| if (! (k instanceof RSAPrivateKey)) |
| throw new IllegalArgumentException(); |
| |
| privateKey = (RSAPrivateKey) k; |
| } |
| |
| protected Object generateSignature() throws IllegalStateException |
| { |
| // 1. Apply the EMSA-PSS encoding operation to the message M to produce an |
| // encoded message EM of length CEILING((modBits ? 1)/8) octets such |
| // that the bit length of the integer OS2IP(EM) is at most modBits ? 1: |
| // EM = EMSA-PSS-Encode(M,modBits ? 1). |
| // Note that the octet length of EM will be one less than k if |
| // modBits ? 1 is divisible by 8. If the encoding operation outputs |
| // 'message too long' or 'encoding error,' then output 'message too |
| // long' or 'encoding error' and stop. |
| int modBits = ((RSAPrivateKey) privateKey).getModulus().bitLength(); |
| byte[] salt = new byte[sLen]; |
| this.nextRandomBytes(salt); |
| byte[] EM = pss.encode(md.digest(), modBits - 1, salt); |
| if (Configuration.DEBUG) |
| log.fine("EM (sign): " + Util.toString(EM)); |
| // 2. Convert the encoded message EM to an integer message representative |
| // m (see Section 1.2.2): m = OS2IP(EM). |
| BigInteger m = new BigInteger(1, EM); |
| // 3. Apply the RSASP signature primitive to the public key K and the |
| // message representative m to produce an integer signature |
| // representative s: s = RSASP(K,m). |
| BigInteger s = RSA.sign(privateKey, m); |
| // 4. Convert the signature representative s to a signature S of length k |
| // octets (see Section 1.2.1): S = I2OSP(s, k). |
| // 5. Output the signature S. |
| int k = (modBits + 7) / 8; |
| // return encodeSignature(s, k); |
| return RSA.I2OSP(s, k); |
| } |
| |
| protected boolean verifySignature(Object sig) throws IllegalStateException |
| { |
| if (publicKey == null) |
| throw new IllegalStateException(); |
| // byte[] S = decodeSignature(sig); |
| byte[] S = (byte[]) sig; |
| // 1. If the length of the signature S is not k octets, output 'signature |
| // invalid' and stop. |
| int modBits = ((RSAPublicKey) publicKey).getModulus().bitLength(); |
| int k = (modBits + 7) / 8; |
| if (S.length != k) |
| return false; |
| // 2. Convert the signature S to an integer signature representative s: |
| // s = OS2IP(S). |
| BigInteger s = new BigInteger(1, S); |
| // 3. Apply the RSAVP verification primitive to the public key (n, e) and |
| // the signature representative s to produce an integer message |
| // representative m: m = RSAVP((n, e), s). |
| // If RSAVP outputs 'signature representative out of range,' then |
| // output 'signature invalid' and stop. |
| BigInteger m = null; |
| try |
| { |
| m = RSA.verify(publicKey, s); |
| } |
| catch (IllegalArgumentException x) |
| { |
| return false; |
| } |
| // 4. Convert the message representative m to an encoded message EM of |
| // length emLen = CEILING((modBits - 1)/8) octets, where modBits is |
| // equal to the bit length of the modulus: EM = I2OSP(m, emLen). |
| // Note that emLen will be one less than k if modBits - 1 is divisible |
| // by 8. If I2OSP outputs 'integer too large,' then output 'signature |
| // invalid' and stop. |
| int emBits = modBits - 1; |
| int emLen = (emBits + 7) / 8; |
| byte[] EM = m.toByteArray(); |
| if (Configuration.DEBUG) |
| log.fine("EM (verify): " + Util.toString(EM)); |
| if (EM.length > emLen) |
| return false; |
| else if (EM.length < emLen) |
| { |
| byte[] newEM = new byte[emLen]; |
| System.arraycopy(EM, 0, newEM, emLen - EM.length, EM.length); |
| EM = newEM; |
| } |
| // 5. Apply the EMSA-PSS decoding operation to the message M and the |
| // encoded message EM: Result = EMSA-PSS-Decode(M, EM, emBits). If |
| // Result = 'consistent,' output 'signature verified.' Otherwise, |
| // output 'signature invalid.' |
| byte[] mHash = md.digest(); |
| boolean result = false; |
| try |
| { |
| result = pss.decode(mHash, EM, emBits, sLen); |
| } |
| catch (IllegalArgumentException x) |
| { |
| result = false; |
| } |
| return result; |
| } |
| } |