org.jboss.security.otp.HOTPUtil Maven / Gradle / Ivy
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* as indicated by the @author tags. See the copyright.txt file in the
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*
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* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
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*/
package org.jboss.security.otp;
import java.security.GeneralSecurityException;
import java.util.Calendar;
import java.util.TimeZone;
/**
* Utility class for {@code HOTP}
* @author [email protected]
* @since Sep 15, 2010
*/
public class HOTPUtil
{
private static final int MILISECOND_BUFFER = 50;
/**
* Validate a submitted OTP string
* @param submittedOTP OTP string to validate
* @param secret Shared secret
* @param timeValueInMins How many mins back we need to check?
* @return
* @throws GeneralSecurityException
*/
public static boolean validate( String submittedOTP, byte[] secret, int timeValueInMins ) throws GeneralSecurityException
{
int codeDigits = 6;
boolean addChecksum = false;
int truncationOffset = 0;
TimeZone utc = TimeZone.getTimeZone( "UTC" );
Calendar currentDateTime = Calendar.getInstance( utc );
long timeInMilis = currentDateTime.getTimeInMillis();
long movingFactor = timeInMilis;
String otp = HOTP.generateOTP( secret, movingFactor, codeDigits, addChecksum, truncationOffset );
if( otp.equals( submittedOTP ) )
return true;
int endLimit = timeValueInMins * 60* 1000 + MILISECOND_BUFFER;
for( int i = 1; i < endLimit ; i++ )
{
movingFactor --;
otp = HOTP.generateOTP( secret, movingFactor, codeDigits, addChecksum, truncationOffset );
if( otp.equals( submittedOTP ) )
return true;
}
return false;
}
}