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	/*
	* Copyright (c) 2001, 2020, 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 8
	*/
	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();
	}
	}

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