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/*
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* Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package sun.security.rsa;
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import java.io.IOException;
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import java.nio.ByteBuffer;
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import java.security.*;
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import java.security.spec.AlgorithmParameterSpec;
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import java.security.spec.PSSParameterSpec;
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import java.security.spec.MGF1ParameterSpec;
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import java.security.interfaces.*;
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import java.util.Arrays;
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import java.util.Hashtable;
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import sun.security.util.*;
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import sun.security.jca.JCAUtil;
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/**
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* PKCS#1 v2.2 RSASSA-PSS signatures with various message digest algorithms.
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* RSASSA-PSS implementation takes the message digest algorithm, MGF algorithm,
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* and salt length values through the required signature PSS parameters.
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* We support SHA-1, SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and
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* SHA-512/256 message digest algorithms and MGF1 mask generation function.
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*
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* @since 11
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*/
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public class RSAPSSSignature extends SignatureSpi {
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private static final boolean DEBUG = false;
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// utility method for comparing digest algorithms
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// NOTE that first argument is assumed to be standard digest name
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private boolean isDigestEqual(String stdAlg, String givenAlg) {
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if (stdAlg == null || givenAlg == null) return false;
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if (givenAlg.indexOf("-") != -1) {
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return stdAlg.equalsIgnoreCase(givenAlg);
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} else {
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if (stdAlg.equals("SHA-1")) {
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return (givenAlg.equalsIgnoreCase("SHA")
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|| givenAlg.equalsIgnoreCase("SHA1"));
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} else {
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StringBuilder sb = new StringBuilder(givenAlg);
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// case-insensitive check
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if (givenAlg.regionMatches(true, 0, "SHA", 0, 3)) {
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givenAlg = sb.insert(3, "-").toString();
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return stdAlg.equalsIgnoreCase(givenAlg);
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} else {
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throw new ProviderException("Unsupported digest algorithm "
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+ givenAlg);
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}
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}
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}
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}
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private static final byte[] EIGHT_BYTES_OF_ZEROS = new byte[8];
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private static final Hashtable<String, Integer> DIGEST_LENGTHS =
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new Hashtable<String, Integer>();
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static {
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DIGEST_LENGTHS.put("SHA-1", 20);
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DIGEST_LENGTHS.put("SHA", 20);
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DIGEST_LENGTHS.put("SHA1", 20);
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DIGEST_LENGTHS.put("SHA-224", 28);
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DIGEST_LENGTHS.put("SHA224", 28);
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DIGEST_LENGTHS.put("SHA-256", 32);
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DIGEST_LENGTHS.put("SHA256", 32);
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DIGEST_LENGTHS.put("SHA-384", 48);
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DIGEST_LENGTHS.put("SHA384", 48);
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DIGEST_LENGTHS.put("SHA-512", 64);
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DIGEST_LENGTHS.put("SHA512", 64);
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DIGEST_LENGTHS.put("SHA-512/224", 28);
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DIGEST_LENGTHS.put("SHA512/224", 28);
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DIGEST_LENGTHS.put("SHA-512/256", 32);
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DIGEST_LENGTHS.put("SHA512/256", 32);
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}
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// message digest implementation we use for hashing the data
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private MessageDigest md;
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// flag indicating whether the digest is reset
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private boolean digestReset = true;
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// private key, if initialized for signing
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private RSAPrivateKey privKey = null;
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// public key, if initialized for verifying
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private RSAPublicKey pubKey = null;
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// PSS parameters from signatures and keys respectively
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private PSSParameterSpec sigParams = null; // required for PSS signatures
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// PRNG used to generate salt bytes if none given
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private SecureRandom random;
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/**
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* Construct a new RSAPSSSignatur with arbitrary digest algorithm
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*/
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public RSAPSSSignature() {
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this.md = null;
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}
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// initialize for verification. See JCA doc
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@Override
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protected void engineInitVerify(PublicKey publicKey)
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throws InvalidKeyException {
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if (!(publicKey instanceof RSAPublicKey)) {
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throw new InvalidKeyException("key must be RSAPublicKey");
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}
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this.pubKey = (RSAPublicKey) isValid((RSAKey)publicKey);
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this.privKey = null;
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}
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// initialize for signing. See JCA doc
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@Override
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protected void engineInitSign(PrivateKey privateKey)
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throws InvalidKeyException {
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engineInitSign(privateKey, null);
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}
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// initialize for signing. See JCA doc
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@Override
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protected void engineInitSign(PrivateKey privateKey, SecureRandom random)
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throws InvalidKeyException {
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if (!(privateKey instanceof RSAPrivateKey)) {
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throw new InvalidKeyException("key must be RSAPrivateKey");
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}
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this.privKey = (RSAPrivateKey) isValid((RSAKey)privateKey);
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this.pubKey = null;
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this.random =
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(random == null? JCAUtil.getSecureRandom() : random);
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}
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/**
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* Utility method for checking the key PSS parameters against signature
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* PSS parameters.
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* Returns false if any of the digest/MGF algorithms and trailerField
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* values does not match or if the salt length in key parameters is
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* larger than the value in signature parameters.
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*/
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private static boolean isCompatible(AlgorithmParameterSpec keyParams,
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PSSParameterSpec sigParams) {
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if (keyParams == null) {
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// key with null PSS parameters means no restriction
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return true;
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}
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if (!(keyParams instanceof PSSParameterSpec)) {
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return false;
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}
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// nothing to compare yet, defer the check to when sigParams is set
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if (sigParams == null) {
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return true;
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}
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PSSParameterSpec pssKeyParams = (PSSParameterSpec) keyParams;
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// first check the salt length requirement
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if (pssKeyParams.getSaltLength() > sigParams.getSaltLength()) {
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return false;
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}
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// compare equality of the rest of fields based on DER encoding
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PSSParameterSpec keyParams2 =
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new PSSParameterSpec(pssKeyParams.getDigestAlgorithm(),
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pssKeyParams.getMGFAlgorithm(),
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pssKeyParams.getMGFParameters(),
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sigParams.getSaltLength(),
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pssKeyParams.getTrailerField());
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PSSParameters ap = new PSSParameters();
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try {
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ap.engineInit(keyParams2);
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byte[] encoded = ap.engineGetEncoded();
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ap.engineInit(sigParams);
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byte[] encoded2 = ap.engineGetEncoded();
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return Arrays.equals(encoded, encoded2);
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} catch (Exception e) {
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if (DEBUG) {
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e.printStackTrace();
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}
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return false;
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}
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}
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/**
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* Validate the specified RSAKey and its associated parameters against
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* internal signature parameters.
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*/
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private RSAKey isValid(RSAKey rsaKey) throws InvalidKeyException {
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try {
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AlgorithmParameterSpec keyParams = rsaKey.getParams();
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// validate key parameters
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if (!isCompatible(rsaKey.getParams(), this.sigParams)) {
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throw new InvalidKeyException
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("Key contains incompatible PSS parameter values");
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}
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// validate key length
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if (this.sigParams != null) {
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Integer hLen =
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DIGEST_LENGTHS.get(this.sigParams.getDigestAlgorithm());
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if (hLen == null) {
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throw new ProviderException("Unsupported digest algo: " +
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this.sigParams.getDigestAlgorithm());
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}
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checkKeyLength(rsaKey, hLen, this.sigParams.getSaltLength());
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}
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return rsaKey;
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} catch (SignatureException e) {
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throw new InvalidKeyException(e);
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}
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}
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/**
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* Validate the specified Signature PSS parameters.
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*/
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private PSSParameterSpec validateSigParams(AlgorithmParameterSpec p)
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throws InvalidAlgorithmParameterException {
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if (p == null) {
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throw new InvalidAlgorithmParameterException
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("Parameters cannot be null");
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}
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if (!(p instanceof PSSParameterSpec)) {
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throw new InvalidAlgorithmParameterException
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("parameters must be type PSSParameterSpec");
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}
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// no need to validate again if same as current signature parameters
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PSSParameterSpec params = (PSSParameterSpec) p;
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if (params == this.sigParams) return params;
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RSAKey key = (this.privKey == null? this.pubKey : this.privKey);
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// check against keyParams if set
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if (key != null) {
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if (!isCompatible(key.getParams(), params)) {
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throw new InvalidAlgorithmParameterException
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("Signature parameters does not match key parameters");
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}
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}
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// now sanity check the parameter values
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if (!(params.getMGFAlgorithm().equalsIgnoreCase("MGF1"))) {
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throw new InvalidAlgorithmParameterException("Only supports MGF1");
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}
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if (params.getTrailerField() != 1) {
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throw new InvalidAlgorithmParameterException
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("Only supports TrailerFieldBC(1)");
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}
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String digestAlgo = params.getDigestAlgorithm();
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// check key length again
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if (key != null) {
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try {
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int hLen = DIGEST_LENGTHS.get(digestAlgo);
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checkKeyLength(key, hLen, params.getSaltLength());
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} catch (SignatureException e) {
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throw new InvalidAlgorithmParameterException(e);
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}
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}
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return params;
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}
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/**
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* Ensure the object is initialized with key and parameters and
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* reset digest
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*/
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private void ensureInit() throws SignatureException {
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RSAKey key = (this.privKey == null? this.pubKey : this.privKey);
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if (key == null) {
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throw new SignatureException("Missing key");
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}
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if (this.sigParams == null) {
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// Parameters are required for signature verification
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throw new SignatureException
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("Parameters required for RSASSA-PSS signatures");
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}
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}
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/**
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* Utility method for checking key length against digest length and
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* salt length
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*/
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private static void checkKeyLength(RSAKey key, int digestLen,
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int saltLen) throws SignatureException {
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if (key != null) {
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int keyLength = getKeyLengthInBits(key) >> 3;
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int minLength = Math.addExact(Math.addExact(digestLen, saltLen), 2);
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if (keyLength < minLength) {
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throw new SignatureException
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("Key is too short, need min " + minLength);
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}
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}
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}
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/**
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* Reset the message digest if it is not already reset.
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*/
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private void resetDigest() {
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if (digestReset == false) {
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this.md.reset();
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digestReset = true;
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}
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}
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/**
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* Return the message digest value.
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*/
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private byte[] getDigestValue() {
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digestReset = true;
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return this.md.digest();
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}
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// update the signature with the plaintext data. See JCA doc
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@Override
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protected void engineUpdate(byte b) throws SignatureException {
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ensureInit();
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this.md.update(b);
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digestReset = false;
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}
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// update the signature with the plaintext data. See JCA doc
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@Override
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protected void engineUpdate(byte[] b, int off, int len)
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throws SignatureException {
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ensureInit();
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this.md.update(b, off, len);
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digestReset = false;
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}
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// update the signature with the plaintext data. See JCA doc
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@Override
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protected void engineUpdate(ByteBuffer b) {
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try {
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ensureInit();
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} catch (SignatureException se) {
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// hack for working around API bug
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throw new RuntimeException(se.getMessage());
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}
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this.md.update(b);
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digestReset = false;
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}
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// sign the data and return the signature. See JCA doc
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@Override
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protected byte[] engineSign() throws SignatureException {
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ensureInit();
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byte[] mHash = getDigestValue();
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try {
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byte[] encoded = encodeSignature(mHash);
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byte[] encrypted = RSACore.rsa(encoded, privKey, true);
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return encrypted;
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} catch (GeneralSecurityException e) {
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throw new SignatureException("Could not sign data", e);
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} catch (IOException e) {
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throw new SignatureException("Could not encode data", e);
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}
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}
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// verify the data and return the result. See JCA doc
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// should be reset to the state after engineInitVerify call.
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@Override
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protected boolean engineVerify(byte[] sigBytes) throws SignatureException {
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ensureInit();
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try {
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if (sigBytes.length != RSACore.getByteLength(this.pubKey)) {
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throw new SignatureException
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("Signature length not correct: got "
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+ sigBytes.length + " but was expecting "
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+ RSACore.getByteLength(this.pubKey));
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}
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byte[] mHash = getDigestValue();
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byte[] decrypted = RSACore.rsa(sigBytes, this.pubKey);
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return decodeSignature(mHash, decrypted);
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} catch (javax.crypto.BadPaddingException e) {
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// occurs if the app has used the wrong RSA public key
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// or if sigBytes is invalid
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// return false rather than propagating the exception for
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// compatibility/ease of use
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return false;
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} catch (IOException e) {
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throw new SignatureException("Signature encoding error", e);
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} finally {
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resetDigest();
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}
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}
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// return the modulus length in bits
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private static int getKeyLengthInBits(RSAKey k) {
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if (k != null) {
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return k.getModulus().bitLength();
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}
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return -1;
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}
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/**
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* Encode the digest 'mHash', return the to-be-signed data.
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* Also used by the PKCS#11 provider.
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*/
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418 |
private byte[] encodeSignature(byte[] mHash)
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419 |
throws IOException, DigestException {
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420 |
AlgorithmParameterSpec mgfParams = this.sigParams.getMGFParameters();
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421 |
String mgfDigestAlgo;
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422 |
if (mgfParams != null) {
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mgfDigestAlgo =
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((MGF1ParameterSpec) mgfParams).getDigestAlgorithm();
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} else {
|
|
426 |
mgfDigestAlgo = this.md.getAlgorithm();
|
|
427 |
}
|
|
428 |
try {
|
|
429 |
int emBits = getKeyLengthInBits(this.privKey) - 1;
|
|
430 |
int emLen =(emBits + 7) >> 3;
|
|
431 |
int hLen = this.md.getDigestLength();
|
|
432 |
int dbLen = emLen - hLen - 1;
|
|
433 |
int sLen = this.sigParams.getSaltLength();
|
|
434 |
|
|
435 |
// maps DB into the corresponding region of EM and
|
|
436 |
// stores its bytes directly into EM
|
|
437 |
byte[] em = new byte[emLen];
|
|
438 |
|
|
439 |
// step7 and some of step8
|
|
440 |
em[dbLen - sLen - 1] = (byte) 1; // set DB's padding2 into EM
|
|
441 |
em[em.length - 1] = (byte) 0xBC; // set trailer field of EM
|
|
442 |
|
|
443 |
if (!digestReset) {
|
|
444 |
throw new ProviderException("Digest should be reset");
|
|
445 |
}
|
|
446 |
// step5: generates M' using padding1, mHash, and salt
|
|
447 |
this.md.update(EIGHT_BYTES_OF_ZEROS);
|
|
448 |
digestReset = false; // mark digest as it now has data
|
|
449 |
this.md.update(mHash);
|
|
450 |
if (sLen != 0) {
|
|
451 |
// step4: generate random salt
|
|
452 |
byte[] salt = new byte[sLen];
|
|
453 |
this.random.nextBytes(salt);
|
|
454 |
this.md.update(salt);
|
|
455 |
|
|
456 |
// step8: set DB's salt into EM
|
|
457 |
System.arraycopy(salt, 0, em, dbLen - sLen, sLen);
|
|
458 |
}
|
|
459 |
// step6: generate H using M'
|
|
460 |
this.md.digest(em, dbLen, hLen); // set H field of EM
|
|
461 |
digestReset = true;
|
|
462 |
|
|
463 |
// step7 and 8 are already covered by the code which setting up
|
|
464 |
// EM as above
|
|
465 |
|
|
466 |
// step9 and 10: feed H into MGF and xor with DB in EM
|
|
467 |
MGF1 mgf1 = new MGF1(mgfDigestAlgo);
|
|
468 |
mgf1.generateAndXor(em, dbLen, hLen, dbLen, em, 0);
|
|
469 |
|
|
470 |
// step11: set the leftmost (8emLen - emBits) bits of the leftmost
|
|
471 |
// octet to 0
|
|
472 |
int numZeroBits = (emLen << 3) - emBits;
|
|
473 |
if (numZeroBits != 0) {
|
|
474 |
byte MASK = (byte) (0xff >>> numZeroBits);
|
|
475 |
em[0] = (byte) (em[0] & MASK);
|
|
476 |
}
|
|
477 |
|
|
478 |
// step12: em should now holds maskedDB || hash h || 0xBC
|
|
479 |
return em;
|
|
480 |
} catch (NoSuchAlgorithmException e) {
|
|
481 |
throw new IOException(e.toString());
|
|
482 |
}
|
|
483 |
}
|
|
484 |
|
|
485 |
/**
|
|
486 |
* Decode the signature data. Verify that the object identifier matches
|
|
487 |
* and return the message digest.
|
|
488 |
*/
|
|
489 |
private boolean decodeSignature(byte[] mHash, byte[] em)
|
|
490 |
throws IOException {
|
|
491 |
int hLen = mHash.length;
|
|
492 |
int sLen = this.sigParams.getSaltLength();
|
|
493 |
int emLen = em.length;
|
|
494 |
int emBits = getKeyLengthInBits(this.pubKey) - 1;
|
|
495 |
|
|
496 |
// step3
|
|
497 |
if (emLen < (hLen + sLen + 2)) {
|
|
498 |
return false;
|
|
499 |
}
|
|
500 |
|
|
501 |
// step4
|
|
502 |
if (em[emLen - 1] != (byte) 0xBC) {
|
|
503 |
return false;
|
|
504 |
}
|
|
505 |
|
|
506 |
// step6: check if the leftmost (8emLen - emBits) bits of the leftmost
|
|
507 |
// octet are 0
|
|
508 |
int numZeroBits = (emLen << 3) - emBits;
|
|
509 |
if (numZeroBits != 0) {
|
|
510 |
byte MASK = (byte) (0xff << (8 - numZeroBits));
|
|
511 |
if ((em[0] & MASK) != 0) {
|
|
512 |
return false;
|
|
513 |
}
|
|
514 |
}
|
|
515 |
String mgfDigestAlgo;
|
|
516 |
AlgorithmParameterSpec mgfParams = this.sigParams.getMGFParameters();
|
|
517 |
if (mgfParams != null) {
|
|
518 |
mgfDigestAlgo =
|
|
519 |
((MGF1ParameterSpec) mgfParams).getDigestAlgorithm();
|
|
520 |
} else {
|
|
521 |
mgfDigestAlgo = this.md.getAlgorithm();
|
|
522 |
}
|
|
523 |
// step 7 and 8
|
|
524 |
int dbLen = emLen - hLen - 1;
|
|
525 |
try {
|
|
526 |
MGF1 mgf1 = new MGF1(mgfDigestAlgo);
|
|
527 |
mgf1.generateAndXor(em, dbLen, hLen, dbLen, em, 0);
|
|
528 |
} catch (NoSuchAlgorithmException nsae) {
|
|
529 |
throw new IOException(nsae.toString());
|
|
530 |
}
|
|
531 |
|
|
532 |
// step9: set the leftmost (8emLen - emBits) bits of the leftmost
|
|
533 |
// octet to 0
|
|
534 |
if (numZeroBits != 0) {
|
|
535 |
byte MASK = (byte) (0xff >>> numZeroBits);
|
|
536 |
em[0] = (byte) (em[0] & MASK);
|
|
537 |
}
|
|
538 |
|
|
539 |
// step10
|
|
540 |
int i = 0;
|
|
541 |
for (; i < dbLen - sLen - 1; i++) {
|
|
542 |
if (em[i] != 0) {
|
|
543 |
return false;
|
|
544 |
}
|
|
545 |
}
|
|
546 |
if (em[i] != 0x01) {
|
|
547 |
return false;
|
|
548 |
}
|
|
549 |
// step12 and 13
|
|
550 |
this.md.update(EIGHT_BYTES_OF_ZEROS);
|
|
551 |
digestReset = false;
|
|
552 |
this.md.update(mHash);
|
|
553 |
if (sLen > 0) {
|
|
554 |
this.md.update(em, (dbLen - sLen), sLen);
|
|
555 |
}
|
|
556 |
byte[] digest2 = this.md.digest();
|
|
557 |
digestReset = true;
|
|
558 |
|
|
559 |
// step14
|
|
560 |
byte[] digestInEM = Arrays.copyOfRange(em, dbLen, emLen - 1);
|
|
561 |
return MessageDigest.isEqual(digest2, digestInEM);
|
|
562 |
}
|
|
563 |
|
|
564 |
// set parameter, not supported. See JCA doc
|
|
565 |
@Deprecated
|
|
566 |
@Override
|
|
567 |
protected void engineSetParameter(String param, Object value)
|
|
568 |
throws InvalidParameterException {
|
|
569 |
throw new UnsupportedOperationException("setParameter() not supported");
|
|
570 |
}
|
|
571 |
|
|
572 |
@Override
|
|
573 |
protected void engineSetParameter(AlgorithmParameterSpec params)
|
|
574 |
throws InvalidAlgorithmParameterException {
|
|
575 |
this.sigParams = validateSigParams(params);
|
|
576 |
// disallow changing parameters when digest has been used
|
|
577 |
if (!digestReset) {
|
|
578 |
throw new ProviderException
|
|
579 |
("Cannot set parameters during operations");
|
|
580 |
}
|
|
581 |
String newHashAlg = this.sigParams.getDigestAlgorithm();
|
|
582 |
// re-allocate md if not yet assigned or algorithm changed
|
|
583 |
if ((this.md == null) ||
|
|
584 |
!(this.md.getAlgorithm().equalsIgnoreCase(newHashAlg))) {
|
|
585 |
try {
|
|
586 |
this.md = MessageDigest.getInstance(newHashAlg);
|
|
587 |
} catch (NoSuchAlgorithmException nsae) {
|
|
588 |
// should not happen as we pick default digest algorithm
|
|
589 |
throw new InvalidAlgorithmParameterException
|
|
590 |
("Unsupported digest algorithm " +
|
|
591 |
newHashAlg, nsae);
|
|
592 |
}
|
|
593 |
}
|
|
594 |
}
|
|
595 |
|
|
596 |
// get parameter, not supported. See JCA doc
|
|
597 |
@Deprecated
|
|
598 |
@Override
|
|
599 |
protected Object engineGetParameter(String param)
|
|
600 |
throws InvalidParameterException {
|
|
601 |
throw new UnsupportedOperationException("getParameter() not supported");
|
|
602 |
}
|
|
603 |
|
|
604 |
@Override
|
|
605 |
protected AlgorithmParameters engineGetParameters() {
|
|
606 |
if (this.sigParams == null) {
|
|
607 |
throw new ProviderException("Missing required PSS parameters");
|
|
608 |
}
|
|
609 |
try {
|
|
610 |
AlgorithmParameters ap =
|
|
611 |
AlgorithmParameters.getInstance("RSASSA-PSS");
|
|
612 |
ap.init(this.sigParams);
|
|
613 |
return ap;
|
|
614 |
} catch (GeneralSecurityException gse) {
|
|
615 |
throw new ProviderException(gse.getMessage());
|
|
616 |
}
|
|
617 |
}
|
|
618 |
}
|