Java tutorial
/* * Copyright (c) 2001, 2019, 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.spec; import java.util.Objects; /** * This class specifies a parameter spec for RSASSA-PSS signature scheme, * as defined in the * <a href="https://tools.ietf.org/rfc/rfc8017.txt">PKCS#1 v2.2</a> standard. * * <p>Its ASN.1 definition in PKCS#1 standard is described below: * <pre> * RSASSA-PSS-params ::= SEQUENCE { * hashAlgorithm [0] HashAlgorithm DEFAULT sha1, * maskGenAlgorithm [1] MaskGenAlgorithm DEFAULT mgf1SHA1, * saltLength [2] INTEGER DEFAULT 20, * trailerField [3] TrailerField DEFAULT trailerFieldBC(1) * } * </pre> * where * <pre> * HashAlgorithm ::= AlgorithmIdentifier { * {OAEP-PSSDigestAlgorithms} * } * MaskGenAlgorithm ::= AlgorithmIdentifier { {PKCS1MGFAlgorithms} } * TrailerField ::= INTEGER { trailerFieldBC(1) } * * OAEP-PSSDigestAlgorithms ALGORITHM-IDENTIFIER ::= { * { OID id-sha1 PARAMETERS NULL }| * { OID id-sha224 PARAMETERS NULL }| * { OID id-sha256 PARAMETERS NULL }| * { OID id-sha384 PARAMETERS NULL }| * { OID id-sha512 PARAMETERS NULL }| * { OID id-sha512-224 PARAMETERS NULL }| * { OID id-sha512-256 PARAMETERS NULL }, * ... -- Allows for future expansion -- * } * PKCS1MGFAlgorithms ALGORITHM-IDENTIFIER ::= { * { OID id-mgf1 PARAMETERS HashAlgorithm }, * ... -- Allows for future expansion -- * } * </pre> * <p>Note: the PSSParameterSpec.DEFAULT uses the following: * message digest -- "SHA-1" * mask generation function (mgf) -- "MGF1" * parameters for mgf -- MGF1ParameterSpec.SHA1 * SaltLength -- 20 * TrailerField -- 1 * * @see MGF1ParameterSpec * @see AlgorithmParameterSpec * @see java.security.Signature * * @author Valerie Peng * * * @since 1.4 */ public class PSSParameterSpec implements AlgorithmParameterSpec { private final String mdName; private final String mgfName; private final AlgorithmParameterSpec mgfSpec; private final int saltLen; private final int trailerField; /** * The {@code TrailerFieldBC} constant as defined in PKCS#1 * * @since 11 */ public static final int TRAILER_FIELD_BC = 1; /** * The PSS parameter set with all default values * * @since 1.5 */ public static final PSSParameterSpec DEFAULT = new PSSParameterSpec("SHA-1", "MGF1", MGF1ParameterSpec.SHA1, 20, TRAILER_FIELD_BC); // disallowed private PSSParameterSpec() { throw new RuntimeException("default constructor not allowed"); } /** * Creates a new {@code PSSParameterSpec} as defined in * the PKCS #1 standard using the specified message digest, * mask generation function, parameters for mask generation * function, salt length, and trailer field values. * * @param mdName the algorithm name of the hash function * @param mgfName the algorithm name of the mask generation function * @param mgfSpec the parameters for the mask generation function. * If null is specified, null will be returned by * getMGFParameters(). * @param saltLen the length of salt * @param trailerField the value of the trailer field * @exception NullPointerException if {@code mdName}, or {@code mgfName} * is null * @exception IllegalArgumentException if {@code saltLen} or * {@code trailerField} is less than 0 * @since 1.5 */ public PSSParameterSpec(String mdName, String mgfName, AlgorithmParameterSpec mgfSpec, int saltLen, int trailerField) { Objects.requireNonNull(mdName, "digest algorithm is null"); Objects.requireNonNull(mgfName, "mask generation function algorithm is null"); if (saltLen < 0) { throw new IllegalArgumentException("negative saltLen value: " + saltLen); } if (trailerField < 0) { throw new IllegalArgumentException("negative trailerField: " + trailerField); } this.mdName = mdName; this.mgfName = mgfName; this.mgfSpec = mgfSpec; this.saltLen = saltLen; this.trailerField = trailerField; } /** * Creates a new {@code PSSParameterSpec} * using the specified salt length and other default values as * defined in PKCS#1. * * @param saltLen the length of salt in bytes to be used in PKCS#1 * PSS encoding * @exception IllegalArgumentException if {@code saltLen} is * less than 0 */ public PSSParameterSpec(int saltLen) { this("SHA-1", "MGF1", MGF1ParameterSpec.SHA1, saltLen, TRAILER_FIELD_BC); } /** * Returns the message digest algorithm name. * * @return the message digest algorithm name * @since 1.5 */ public String getDigestAlgorithm() { return mdName; } /** * Returns the mask generation function algorithm name. * * @return the mask generation function algorithm name * * @since 1.5 */ public String getMGFAlgorithm() { return mgfName; } /** * Returns the parameters for the mask generation function. * * @return the parameters for the mask generation function * @since 1.5 */ public AlgorithmParameterSpec getMGFParameters() { return mgfSpec; } /** * Returns the salt length in bytes. * * @return the salt length */ public int getSaltLength() { return saltLen; } /** * Returns the value for the trailer field. * * @return the value for the trailer field * @since 1.5 */ public int getTrailerField() { return trailerField; } @Override public String toString() { StringBuilder sb = new StringBuilder(); sb.append("MD: " + mdName + "\n").append("MGF: " + mgfSpec + "\n").append("SaltLength: " + saltLen + "\n") .append("TrailerField: " + trailerField + "\n"); return sb.toString(); } }