Its ASN.1 definition in the PKCS #1 standard is described below: *
* 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)
* }
*
* where
*
* 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 --
* }
*
*
* @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 the PKCS #1 standard.
*
* @since 11
*/
public static final int TRAILER_FIELD_BC = 1;
/**
* The PSS parameter set with all default values.
* @deprecated This field uses the default values defined in the PKCS #1
* standard. Some of these defaults are no longer recommended due
* to advances in cryptanalysis -- see the
* PKCS#1 v2.2
* standard for more details. Thus, it is recommended to create
* a new {@code PSSParameterSpec} with the desired parameter values
* using the
* {@link #PSSParameterSpec(String, String, AlgorithmParameterSpec, int, int)} constructor.
*
* @since 1.5
*/
@Deprecated(since="19")
public static final PSSParameterSpec DEFAULT = new PSSParameterSpec
("SHA-1", "MGF1", MGF1ParameterSpec.SHA1, 20, TRAILER_FIELD_BC);
/**
* 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 in bytes
* @param trailerField the value of the trailer field
* @throws NullPointerException if {@code mdName}, or {@code mgfName}
* is null
* @throws 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 the PKCS #1 standard.
*
* @param saltLen the length of salt in bytes
* @throws IllegalArgumentException if {@code saltLen} is
* less than 0
* @deprecated This constructor uses the default values defined in
* the PKCS #1 standard except for the salt length. Some of these
* defaults are no longer recommended due to advances in
* cryptanalysis -- see the
* PKCS#1 v2.2
* standard for more details. Thus, it is recommended to explicitly
* specify all desired parameter values with the
* {@link #PSSParameterSpec(String, String, AlgorithmParameterSpec, int, int)} constructor.
*/
@Deprecated(since="19")
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() {
return "PSSParameterSpec[" + "hashAlgorithm=" + mdName + ", " +
"maskGenAlgorithm=" + mgfSpec + ", " +
"saltLength=" + saltLen + ", " +
"trailerField=" + trailerField +
']';
}
}