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gnu.javax.crypto.sasl.srp

Class PasswordFile

public class PasswordFile
extends Object
The implementation of SRP password files.

For SRP, there are three (3) files:

  1. The password configuration file: tpasswd.conf. It contains the pairs <N,g> indexed by a number for each pair used for a user. By default, this file's pathname is constructed from the base password file pathname by prepending it with the ".conf" suffix.
  2. The base password file: tpasswd. It contains the related password entries for all the users with values computed using SRP's default message digest algorithm: SHA-1 (with 160-bit output block size).
  3. The extended password file: tpasswd2. Its name, by default, is constructed by adding the suffix "2" to the fully qualified pathname of the base password file. It contains, in addition to the same fields as the base password file, albeit with a different verifier value, an extra field identifying the message digest algorithm used to compute this (verifier) value.

This implementation assumes the following message digest algorithm codes:

IMPORTANT: This method computes the verifiers as described in RFC-2945, which differs from the description given on the web page for SRP-6.

Reference:

  1. SRP Protocol Design
    Thomas J. Wu.

Constructor Summary

PasswordFile()
The basic constructor.
PasswordFile(File pwFile)
PasswordFile(String pwName)
PasswordFile(String pwName, String confName)
PasswordFile(String pwName, String pw2Name, String confName)

Method Summary

void
add(String user, String passwd, byte[] salt, String index)
void
changePasswd(String user, String passwd)
boolean
contains(String user)
boolean
containsConfig(String index)
Checks if the current configuration file contains the <N, g> pair for the designated index.
String[]
lookup(String user, String mdName)
Returns the triplet: verifier, salt and configuration file index, of a designated user, and a designated message digest algorithm name, as an array of strings.
String[]
lookupConfig(String index)
Returns a pair of strings representing the pair of N and g MPIs for the designated index.
void
savePasswd()

Methods inherited from class java.lang.Object

clone, equals, extends Object> getClass, finalize, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

PasswordFile

public PasswordFile()
            throws IOException
The basic constructor. Object is special, because it has no superclass, so there is no call to super().

PasswordFile

public PasswordFile(File pwFile)
            throws IOException

PasswordFile

public PasswordFile(String pwName)
            throws IOException

PasswordFile

public PasswordFile(String pwName,
                    String confName)
            throws IOException

PasswordFile

public PasswordFile(String pwName,
                    String pw2Name,
                    String confName)
            throws IOException

Method Details

add

public void add(String user,
                String passwd,
                byte[] salt,
                String index)
            throws IOException

changePasswd

public void changePasswd(String user,
                         String passwd)
            throws IOException

contains

public boolean contains(String user)
            throws IOException

containsConfig

public boolean containsConfig(String index)
            throws IOException
Checks if the current configuration file contains the <N, g> pair for the designated index.
Parameters:
index - a string representing 1-digit identification of an <N, g> pair used.
Returns:
true if the designated index is that of a known <N, g> pair, and false otherwise.
Throws:
IOException - if an exception occurs during the process.
See Also:
SRPRegistry.N_2048_BITS, SRPRegistry.N_1536_BITS, SRPRegistry.N_1280_BITS, SRPRegistry.N_1024_BITS, SRPRegistry.N_768_BITS, SRPRegistry.N_640_BITS, SRPRegistry.N_512_BITS

lookup

public String[] lookup(String user,
                       String mdName)
            throws IOException
Returns the triplet: verifier, salt and configuration file index, of a designated user, and a designated message digest algorithm name, as an array of strings.
Parameters:
user - the username.
mdName - the canonical name of the SRP's message digest algorithm.
Returns:
a string array containing, in this order, the BASE-64 encodings of the verifier, the salt and the index in the password configuration file of the MPIs N and g of the designated user.

lookupConfig

public String[] lookupConfig(String index)
            throws IOException
Returns a pair of strings representing the pair of N and g MPIs for the designated index.
Parameters:
index - a string representing 1-digit identification of an <N, g> pair to look up.
Returns:
a pair of strings, arranged in an array, where the first (at index position #0) is the repesentation of the MPI N, and the second (at index position #1) is the representation of the MPI g. If the index refers to an unknown pair, then an empty string array is returned.
Throws:
IOException - if an exception occurs during the process.

savePasswd

public void savePasswd()
            throws IOException
PasswordFile.java -- Copyright (C) 2003, 2006 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.

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