/****************************************************************************
* Copyright (C) 2012 ecsec GmbH.
* All rights reserved.
* Contact: ecsec GmbH (info@ecsec.de)
*
* This file is part of the Open eCard App.
*
* GNU General Public License Usage
* This file may be used under the terms of the GNU General Public
* License version 3.0 as published by the Free Software Foundation
* and appearing in the file LICENSE.GPL included in the packaging of
* this file. Please review the following information to ensure the
* GNU General Public License version 3.0 requirements will be met:
* http://www.gnu.org/copyleft/gpl.html.
*
* Other Usage
* Alternatively, this file may be used in accordance with the terms
* and conditions contained in a signed written agreement between
* you and ecsec GmbH.
*
***************************************************************************/
package org.openecard.common.util;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
*
* @author Tobias Wich <tobias.wich@ecsec.de>
*/
public class ValueValidator {
/**
* Check if the value contains at least the given number of bytes as hex digits.
*
* @deprecated Renamed to {@link #checkHexByteStrength(java.lang.String, int)
* @param value Value to test for hex digits.
* @param numBytes Number of bytes that must be present in the value.
* @return true if enough bytes are present, false otherwise.
*/
@Deprecated
public static boolean checkHexStrength(String value, int numBytes) {
return checkHexNibbleStrength(value, numBytes * 2);
}
/**
* Check if the value contains at least the given number of bytes as hex digits.
*
* @param value Value to test for hex digits.
* @param numBytes Number of bytes that must be present in the value.
* @return true if enough bytes are present, false otherwise.
*/
public static boolean checkHexByteStrength(String value, int numBytes) {
return checkHexNibbleStrength(value, numBytes * 2);
}
/**
* Check if the value contains at least the given number of half-bytes as hex digits.
*
* @param value Value to test for hex digits.
* @param numNibbles Number of half-bytes that must be present in the value.
* @return true if enough bytes are present, false otherwise.
*/
public static boolean checkHexNibbleStrength(String value, int numNibbles) {
Pattern p = Pattern.compile("\\p{XDigit}{1}");
Matcher m = p.matcher(value);
int count = 0;
while (m.find()) {
count++;
}
return count >= numNibbles;
}
/**
* Check if the psk value is strong enough.
* PSKs must at least contain 16 bytes as hex digits.
*
* @param psk PSK value to test.
* @return true if psk is strong enough, false otherwise.
*/
public static boolean checkPSKStrength(String psk) {
return checkHexByteStrength(psk, 16);
}
/**
* Check if the session ID value is strong enough.
* Session IDs must at least contain 25 half-bytes as hex digits. BSI TR-03112 sec. 3.7.1 demands that session IDs
* must have at least 100 bits of entropy which is exactly 25 nibbles.
*
* @param session Session ID value to test.
* @return true if session ID is strong enough, false otherwise.
*/
public static boolean checkSessionStrength(String session) {
return checkHexNibbleStrength(session, 25);
}
}